Esempio n. 1
0
/* Subroutine */ int zchksy_(logical *dotype, integer *nn, integer *nval, 
	integer *nnb, integer *nbval, integer *nns, integer *nsval, 
	doublereal *thresh, logical *tsterr, integer *nmax, doublecomplex *a, 
	doublecomplex *afac, doublecomplex *ainv, doublecomplex *b, 
	doublecomplex *x, doublecomplex *xact, doublecomplex *work, 
	doublereal *rwork, integer *iwork, integer *nout)
{
    /* Initialized data */

    static integer iseedy[4] = { 1988,1989,1990,1991 };
    static char uplos[1*2] = "U" "L";

    /* Format strings */
    static char fmt_9999[] = "(\002 UPLO = '\002,a1,\002', N =\002,i5,\002, "
	    "NB =\002,i4,\002, type \002,i2,\002, test \002,i2,\002, ratio "
	    "=\002,g12.5)";
    static char fmt_9998[] = "(\002 UPLO = '\002,a1,\002', N =\002,i5,\002, "
	    "NRHS=\002,i3,\002, type \002,i2,\002, test(\002,i2,\002) =\002,g"
	    "12.5)";
    static char fmt_9997[] = "(\002 UPLO = '\002,a1,\002', N =\002,i5,\002"
	    ",\002,10x,\002 type \002,i2,\002, test(\002,i2,\002) =\002,g12.5)"
	    ;

    /* System generated locals */
    integer i__1, i__2, i__3, i__4, i__5;

    /* Builtin functions */
    /* Subroutine */ int s_copy(char *, char *, ftnlen, ftnlen);
    integer s_wsfe(cilist *), do_fio(integer *, char *, ftnlen), e_wsfe(void);

    /* Local variables */
    integer i__, j, k, n, i1, i2, nb, in, kl, ku, nt, lda, inb, ioff, mode, 
	    imat, info;
    char path[3], dist[1];
    integer irhs, nrhs;
    char uplo[1], type__[1];
    integer nrun;
    extern /* Subroutine */ int alahd_(integer *, char *);
    integer nfail, iseed[4];
    extern doublereal dget06_(doublereal *, doublereal *);
    doublereal rcond;
    integer nimat;
    doublereal anorm;
    extern /* Subroutine */ int zget04_(integer *, integer *, doublecomplex *, 
	     integer *, doublecomplex *, integer *, doublereal *, doublereal *
);
    integer iuplo, izero, nerrs, lwork;
    extern /* Subroutine */ int zpot05_(char *, integer *, integer *, 
	    doublecomplex *, integer *, doublecomplex *, integer *, 
	    doublecomplex *, integer *, doublecomplex *, integer *, 
	    doublereal *, doublereal *, doublereal *);
    logical zerot;
    char xtype[1];
    extern /* Subroutine */ int zsyt01_(char *, integer *, doublecomplex *, 
	    integer *, doublecomplex *, integer *, integer *, doublecomplex *, 
	     integer *, doublereal *, doublereal *), zsyt02_(char *, 
	    integer *, integer *, doublecomplex *, integer *, doublecomplex *, 
	     integer *, doublecomplex *, integer *, doublereal *, doublereal *
), zsyt03_(char *, integer *, doublecomplex *, integer *, 
	    doublecomplex *, integer *, doublecomplex *, integer *, 
	    doublereal *, doublereal *, doublereal *), zlatb4_(char *, 
	     integer *, integer *, integer *, char *, integer *, integer *, 
	    doublereal *, integer *, doublereal *, char *), alaerh_(char *, char *, integer *, integer *, char *, 
	    integer *, integer *, integer *, integer *, integer *, integer *, 
	    integer *, integer *, integer *);
    doublereal rcondc;
    extern /* Subroutine */ int alasum_(char *, integer *, integer *, integer 
	    *, integer *);
    doublereal cndnum;
    logical trfcon;
    extern /* Subroutine */ int xlaenv_(integer *, integer *), zlacpy_(char *, 
	     integer *, integer *, doublecomplex *, integer *, doublecomplex *
, integer *), zlarhs_(char *, char *, char *, char *, 
	    integer *, integer *, integer *, integer *, integer *, 
	    doublecomplex *, integer *, doublecomplex *, integer *, 
	    doublecomplex *, integer *, integer *, integer *), zlatms_(integer *, integer *, char *, integer *, 
	    char *, doublereal *, integer *, doublereal *, doublereal *, 
	    integer *, integer *, char *, doublecomplex *, integer *, 
	    doublecomplex *, integer *);
    doublereal result[8];
    extern doublereal zlansy_(char *, char *, integer *, doublecomplex *, 
	    integer *, doublereal *);
    extern /* Subroutine */ int zsycon_(char *, integer *, doublecomplex *, 
	    integer *, integer *, doublereal *, doublereal *, doublecomplex *, 
	     integer *), zlatsy_(char *, integer *, doublecomplex *, 
	    integer *, integer *), zerrsy_(char *, integer *),
	     zsyrfs_(char *, integer *, integer *, doublecomplex *, integer *, 
	     doublecomplex *, integer *, integer *, doublecomplex *, integer *
, doublecomplex *, integer *, doublereal *, doublereal *, 
	    doublecomplex *, doublereal *, integer *), zsytrf_(char *, 
	     integer *, doublecomplex *, integer *, integer *, doublecomplex *
, integer *, integer *), zsytri_(char *, integer *, 
	    doublecomplex *, integer *, integer *, doublecomplex *, integer *), zsytrs_(char *, integer *, integer *, doublecomplex *, 
	    integer *, integer *, doublecomplex *, integer *, integer *);

    /* Fortran I/O blocks */
    static cilist io___39 = { 0, 0, 0, fmt_9999, 0 };
    static cilist io___42 = { 0, 0, 0, fmt_9998, 0 };
    static cilist io___44 = { 0, 0, 0, fmt_9997, 0 };



/*  -- LAPACK test routine (version 3.1) -- */
/*     Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */
/*     November 2006 */

/*     .. Scalar Arguments .. */
/*     .. */
/*     .. Array Arguments .. */
/*     .. */

/*  Purpose */
/*  ======= */

/*  ZCHKSY tests ZSYTRF, -TRI, -TRS, -RFS, and -CON. */

/*  Arguments */
/*  ========= */

/*  DOTYPE  (input) LOGICAL array, dimension (NTYPES) */
/*          The matrix types to be used for testing.  Matrices of type j */
/*          (for 1 <= j <= NTYPES) are used for testing if DOTYPE(j) = */
/*          .TRUE.; if DOTYPE(j) = .FALSE., then type j is not used. */

/*  NN      (input) INTEGER */
/*          The number of values of N contained in the vector NVAL. */

/*  NVAL    (input) INTEGER array, dimension (NN) */
/*          The values of the matrix dimension N. */

/*  NNB     (input) INTEGER */
/*          The number of values of NB contained in the vector NBVAL. */

/*  NBVAL   (input) INTEGER array, dimension (NBVAL) */
/*          The values of the blocksize NB. */

/*  NNS     (input) INTEGER */
/*          The number of values of NRHS contained in the vector NSVAL. */

/*  NSVAL   (input) INTEGER array, dimension (NNS) */
/*          The values of the number of right hand sides NRHS. */

/*  THRESH  (input) DOUBLE PRECISION */
/*          The threshold value for the test ratios.  A result is */
/*          included in the output file if RESULT >= THRESH.  To have */
/*          every test ratio printed, use THRESH = 0. */

/*  TSTERR  (input) LOGICAL */
/*          Flag that indicates whether error exits are to be tested. */

/*  NMAX    (input) INTEGER */
/*          The maximum value permitted for N, used in dimensioning the */
/*          work arrays. */

/*  A       (workspace) COMPLEX*16 array, dimension (NMAX*NMAX) */

/*  AFAC    (workspace) COMPLEX*16 array, dimension (NMAX*NMAX) */

/*  AINV    (workspace) COMPLEX*16 array, dimension (NMAX*NMAX) */

/*  B       (workspace) COMPLEX*16 array, dimension (NMAX*NSMAX) */
/*          where NSMAX is the largest entry in NSVAL. */

/*  X       (workspace) COMPLEX*16 array, dimension (NMAX*NSMAX) */

/*  XACT    (workspace) COMPLEX*16 array, dimension (NMAX*NSMAX) */

/*  WORK    (workspace) COMPLEX*16 array, dimension */
/*                      (NMAX*max(2,NSMAX)) */

/*  RWORK   (workspace) DOUBLE PRECISION array, */
/*                                 dimension (NMAX+2*NSMAX) */

/*  IWORK   (workspace) INTEGER array, dimension (NMAX) */

/*  NOUT    (input) INTEGER */
/*          The unit number for output. */

/*  ===================================================================== */

/*     .. Parameters .. */
/*     .. */
/*     .. Local Scalars .. */
/*     .. */
/*     .. Local Arrays .. */
/*     .. */
/*     .. External Functions .. */
/*     .. */
/*     .. External Subroutines .. */
/*     .. */
/*     .. Intrinsic Functions .. */
/*     .. */
/*     .. Scalars in Common .. */
/*     .. */
/*     .. Common blocks .. */
/*     .. */
/*     .. Data statements .. */
    /* Parameter adjustments */
    --iwork;
    --rwork;
    --work;
    --xact;
    --x;
    --b;
    --ainv;
    --afac;
    --a;
    --nsval;
    --nbval;
    --nval;
    --dotype;

    /* Function Body */
/*     .. */
/*     .. Executable Statements .. */

/*     Initialize constants and the random number seed. */

    s_copy(path, "Zomplex precision", (ftnlen)1, (ftnlen)17);
    s_copy(path + 1, "SY", (ftnlen)2, (ftnlen)2);
    nrun = 0;
    nfail = 0;
    nerrs = 0;
    for (i__ = 1; i__ <= 4; ++i__) {
	iseed[i__ - 1] = iseedy[i__ - 1];
/* L10: */
    }

/*     Test the error exits */

    if (*tsterr) {
	zerrsy_(path, nout);
    }
    infoc_1.infot = 0;

/*     Do for each value of N in NVAL */

    i__1 = *nn;
    for (in = 1; in <= i__1; ++in) {
	n = nval[in];
	lda = max(n,1);
	*(unsigned char *)xtype = 'N';
	nimat = 11;
	if (n <= 0) {
	    nimat = 1;
	}

	izero = 0;
	i__2 = nimat;
	for (imat = 1; imat <= i__2; ++imat) {

/*           Do the tests only if DOTYPE( IMAT ) is true. */

	    if (! dotype[imat]) {
		goto L170;
	    }

/*           Skip types 3, 4, 5, or 6 if the matrix size is too small. */

	    zerot = imat >= 3 && imat <= 6;
	    if (zerot && n < imat - 2) {
		goto L170;
	    }

/*           Do first for UPLO = 'U', then for UPLO = 'L' */

	    for (iuplo = 1; iuplo <= 2; ++iuplo) {
		*(unsigned char *)uplo = *(unsigned char *)&uplos[iuplo - 1];

		if (imat != 11) {

/*                 Set up parameters with ZLATB4 and generate a test */
/*                 matrix with ZLATMS. */

		    zlatb4_(path, &imat, &n, &n, type__, &kl, &ku, &anorm, &
			    mode, &cndnum, dist);

		    s_copy(srnamc_1.srnamt, "ZLATMS", (ftnlen)6, (ftnlen)6);
		    zlatms_(&n, &n, dist, iseed, type__, &rwork[1], &mode, &
			    cndnum, &anorm, &kl, &ku, "N", &a[1], &lda, &work[
			    1], &info);

/*                 Check error code from ZLATMS. */

		    if (info != 0) {
			alaerh_(path, "ZLATMS", &info, &c__0, uplo, &n, &n, &
				c_n1, &c_n1, &c_n1, &imat, &nfail, &nerrs, 
				nout);
			goto L160;
		    }

/*                 For types 3-6, zero one or more rows and columns of */
/*                 the matrix to test that INFO is returned correctly. */

		    if (zerot) {
			if (imat == 3) {
			    izero = 1;
			} else if (imat == 4) {
			    izero = n;
			} else {
			    izero = n / 2 + 1;
			}

			if (imat < 6) {

/*                       Set row and column IZERO to zero. */

			    if (iuplo == 1) {
				ioff = (izero - 1) * lda;
				i__3 = izero - 1;
				for (i__ = 1; i__ <= i__3; ++i__) {
				    i__4 = ioff + i__;
				    a[i__4].r = 0., a[i__4].i = 0.;
/* L20: */
				}
				ioff += izero;
				i__3 = n;
				for (i__ = izero; i__ <= i__3; ++i__) {
				    i__4 = ioff;
				    a[i__4].r = 0., a[i__4].i = 0.;
				    ioff += lda;
/* L30: */
				}
			    } else {
				ioff = izero;
				i__3 = izero - 1;
				for (i__ = 1; i__ <= i__3; ++i__) {
				    i__4 = ioff;
				    a[i__4].r = 0., a[i__4].i = 0.;
				    ioff += lda;
/* L40: */
				}
				ioff -= izero;
				i__3 = n;
				for (i__ = izero; i__ <= i__3; ++i__) {
				    i__4 = ioff + i__;
				    a[i__4].r = 0., a[i__4].i = 0.;
/* L50: */
				}
			    }
			} else {
			    if (iuplo == 1) {

/*                          Set the first IZERO rows to zero. */

				ioff = 0;
				i__3 = n;
				for (j = 1; j <= i__3; ++j) {
				    i2 = min(j,izero);
				    i__4 = i2;
				    for (i__ = 1; i__ <= i__4; ++i__) {
					i__5 = ioff + i__;
					a[i__5].r = 0., a[i__5].i = 0.;
/* L60: */
				    }
				    ioff += lda;
/* L70: */
				}
			    } else {

/*                          Set the last IZERO rows to zero. */

				ioff = 0;
				i__3 = n;
				for (j = 1; j <= i__3; ++j) {
				    i1 = max(j,izero);
				    i__4 = n;
				    for (i__ = i1; i__ <= i__4; ++i__) {
					i__5 = ioff + i__;
					a[i__5].r = 0., a[i__5].i = 0.;
/* L80: */
				    }
				    ioff += lda;
/* L90: */
				}
			    }
			}
		    } else {
			izero = 0;
		    }
		} else {

/*                 Use a special block diagonal matrix to test alternate */
/*                 code for the 2 x 2 blocks. */

		    zlatsy_(uplo, &n, &a[1], &lda, iseed);
		}

/*              Do for each value of NB in NBVAL */

		i__3 = *nnb;
		for (inb = 1; inb <= i__3; ++inb) {
		    nb = nbval[inb];
		    xlaenv_(&c__1, &nb);

/*                 Compute the L*D*L' or U*D*U' factorization of the */
/*                 matrix. */

		    zlacpy_(uplo, &n, &n, &a[1], &lda, &afac[1], &lda);
		    lwork = max(2,nb) * lda;
		    s_copy(srnamc_1.srnamt, "ZSYTRF", (ftnlen)6, (ftnlen)6);
		    zsytrf_(uplo, &n, &afac[1], &lda, &iwork[1], &ainv[1], &
			    lwork, &info);

/*                 Adjust the expected value of INFO to account for */
/*                 pivoting. */

		    k = izero;
		    if (k > 0) {
L100:
			if (iwork[k] < 0) {
			    if (iwork[k] != -k) {
				k = -iwork[k];
				goto L100;
			    }
			} else if (iwork[k] != k) {
			    k = iwork[k];
			    goto L100;
			}
		    }

/*                 Check error code from ZSYTRF. */

		    if (info != k) {
			alaerh_(path, "ZSYTRF", &info, &k, uplo, &n, &n, &
				c_n1, &c_n1, &nb, &imat, &nfail, &nerrs, nout);
		    }
		    if (info != 0) {
			trfcon = TRUE_;
		    } else {
			trfcon = FALSE_;
		    }

/* +    TEST 1 */
/*                 Reconstruct matrix from factors and compute residual. */

		    zsyt01_(uplo, &n, &a[1], &lda, &afac[1], &lda, &iwork[1], 
			    &ainv[1], &lda, &rwork[1], result);
		    nt = 1;

/* +    TEST 2 */
/*                 Form the inverse and compute the residual. */

		    if (inb == 1 && ! trfcon) {
			zlacpy_(uplo, &n, &n, &afac[1], &lda, &ainv[1], &lda);
			s_copy(srnamc_1.srnamt, "ZSYTRI", (ftnlen)6, (ftnlen)
				6);
			zsytri_(uplo, &n, &ainv[1], &lda, &iwork[1], &work[1], 
				 &info);

/*                 Check error code from ZSYTRI. */

			if (info != 0) {
			    alaerh_(path, "ZSYTRI", &info, &c__0, uplo, &n, &
				    n, &c_n1, &c_n1, &c_n1, &imat, &nfail, &
				    nerrs, nout);
			}

			zsyt03_(uplo, &n, &a[1], &lda, &ainv[1], &lda, &work[
				1], &lda, &rwork[1], &rcondc, &result[1]);
			nt = 2;
		    }

/*                 Print information about the tests that did not pass */
/*                 the threshold. */

		    i__4 = nt;
		    for (k = 1; k <= i__4; ++k) {
			if (result[k - 1] >= *thresh) {
			    if (nfail == 0 && nerrs == 0) {
				alahd_(nout, path);
			    }
			    io___39.ciunit = *nout;
			    s_wsfe(&io___39);
			    do_fio(&c__1, uplo, (ftnlen)1);
			    do_fio(&c__1, (char *)&n, (ftnlen)sizeof(integer))
				    ;
			    do_fio(&c__1, (char *)&nb, (ftnlen)sizeof(integer)
				    );
			    do_fio(&c__1, (char *)&imat, (ftnlen)sizeof(
				    integer));
			    do_fio(&c__1, (char *)&k, (ftnlen)sizeof(integer))
				    ;
			    do_fio(&c__1, (char *)&result[k - 1], (ftnlen)
				    sizeof(doublereal));
			    e_wsfe();
			    ++nfail;
			}
/* L110: */
		    }
		    nrun += nt;

/*                 Skip the other tests if this is not the first block */
/*                 size. */

		    if (inb > 1) {
			goto L150;
		    }

/*                 Do only the condition estimate if INFO is not 0. */

		    if (trfcon) {
			rcondc = 0.;
			goto L140;
		    }

		    i__4 = *nns;
		    for (irhs = 1; irhs <= i__4; ++irhs) {
			nrhs = nsval[irhs];

/* +    TEST 3 */
/*                 Solve and compute residual for  A * X = B. */

			s_copy(srnamc_1.srnamt, "ZLARHS", (ftnlen)6, (ftnlen)
				6);
			zlarhs_(path, xtype, uplo, " ", &n, &n, &kl, &ku, &
				nrhs, &a[1], &lda, &xact[1], &lda, &b[1], &
				lda, iseed, &info);
			zlacpy_("Full", &n, &nrhs, &b[1], &lda, &x[1], &lda);

			s_copy(srnamc_1.srnamt, "ZSYTRS", (ftnlen)6, (ftnlen)
				6);
			zsytrs_(uplo, &n, &nrhs, &afac[1], &lda, &iwork[1], &
				x[1], &lda, &info);

/*                 Check error code from ZSYTRS. */

			if (info != 0) {
			    alaerh_(path, "ZSYTRS", &info, &c__0, uplo, &n, &
				    n, &c_n1, &c_n1, &nrhs, &imat, &nfail, &
				    nerrs, nout);
			}

			zlacpy_("Full", &n, &nrhs, &b[1], &lda, &work[1], &
				lda);
			zsyt02_(uplo, &n, &nrhs, &a[1], &lda, &x[1], &lda, &
				work[1], &lda, &rwork[1], &result[2]);

/* +    TEST 4 */
/*                 Check solution from generated exact solution. */

			zget04_(&n, &nrhs, &x[1], &lda, &xact[1], &lda, &
				rcondc, &result[3]);

/* +    TESTS 5, 6, and 7 */
/*                 Use iterative refinement to improve the solution. */

			s_copy(srnamc_1.srnamt, "ZSYRFS", (ftnlen)6, (ftnlen)
				6);
			zsyrfs_(uplo, &n, &nrhs, &a[1], &lda, &afac[1], &lda, 
				&iwork[1], &b[1], &lda, &x[1], &lda, &rwork[1]
, &rwork[nrhs + 1], &work[1], &rwork[(nrhs << 
				1) + 1], &info);

/*                 Check error code from ZSYRFS. */

			if (info != 0) {
			    alaerh_(path, "ZSYRFS", &info, &c__0, uplo, &n, &
				    n, &c_n1, &c_n1, &nrhs, &imat, &nfail, &
				    nerrs, nout);
			}

			zget04_(&n, &nrhs, &x[1], &lda, &xact[1], &lda, &
				rcondc, &result[4]);
			zpot05_(uplo, &n, &nrhs, &a[1], &lda, &b[1], &lda, &x[
				1], &lda, &xact[1], &lda, &rwork[1], &rwork[
				nrhs + 1], &result[5]);

/*                    Print information about the tests that did not pass */
/*                    the threshold. */

			for (k = 3; k <= 7; ++k) {
			    if (result[k - 1] >= *thresh) {
				if (nfail == 0 && nerrs == 0) {
				    alahd_(nout, path);
				}
				io___42.ciunit = *nout;
				s_wsfe(&io___42);
				do_fio(&c__1, uplo, (ftnlen)1);
				do_fio(&c__1, (char *)&n, (ftnlen)sizeof(
					integer));
				do_fio(&c__1, (char *)&nrhs, (ftnlen)sizeof(
					integer));
				do_fio(&c__1, (char *)&imat, (ftnlen)sizeof(
					integer));
				do_fio(&c__1, (char *)&k, (ftnlen)sizeof(
					integer));
				do_fio(&c__1, (char *)&result[k - 1], (ftnlen)
					sizeof(doublereal));
				e_wsfe();
				++nfail;
			    }
/* L120: */
			}
			nrun += 5;
/* L130: */
		    }

/* +    TEST 8 */
/*                 Get an estimate of RCOND = 1/CNDNUM. */

L140:
		    anorm = zlansy_("1", uplo, &n, &a[1], &lda, &rwork[1]);
		    s_copy(srnamc_1.srnamt, "ZSYCON", (ftnlen)6, (ftnlen)6);
		    zsycon_(uplo, &n, &afac[1], &lda, &iwork[1], &anorm, &
			    rcond, &work[1], &info);

/*                 Check error code from ZSYCON. */

		    if (info != 0) {
			alaerh_(path, "ZSYCON", &info, &c__0, uplo, &n, &n, &
				c_n1, &c_n1, &c_n1, &imat, &nfail, &nerrs, 
				nout);
		    }

		    result[7] = dget06_(&rcond, &rcondc);

/*                 Print information about the tests that did not pass */
/*                 the threshold. */

		    if (result[7] >= *thresh) {
			if (nfail == 0 && nerrs == 0) {
			    alahd_(nout, path);
			}
			io___44.ciunit = *nout;
			s_wsfe(&io___44);
			do_fio(&c__1, uplo, (ftnlen)1);
			do_fio(&c__1, (char *)&n, (ftnlen)sizeof(integer));
			do_fio(&c__1, (char *)&imat, (ftnlen)sizeof(integer));
			do_fio(&c__1, (char *)&c__8, (ftnlen)sizeof(integer));
			do_fio(&c__1, (char *)&result[7], (ftnlen)sizeof(
				doublereal));
			e_wsfe();
			++nfail;
		    }
		    ++nrun;
L150:
		    ;
		}
L160:
		;
	    }
L170:
	    ;
	}
/* L180: */
    }

/*     Print a summary of the results. */

    alasum_(path, nout, &nfail, &nrun, &nerrs);

    return 0;

/*     End of ZCHKSY */

} /* zchksy_ */
Esempio n. 2
0
/* Subroutine */ int zsyrfs_(char *uplo, integer *n, integer *nrhs, 
	doublecomplex *a, integer *lda, doublecomplex *af, integer *ldaf, 
	integer *ipiv, doublecomplex *b, integer *ldb, doublecomplex *x, 
	integer *ldx, doublereal *ferr, doublereal *berr, doublecomplex *work, 
	 doublereal *rwork, integer *info)
{
    /* System generated locals */
    integer a_dim1, a_offset, af_dim1, af_offset, b_dim1, b_offset, x_dim1, 
	    x_offset, i__1, i__2, i__3, i__4, i__5;
    doublereal d__1, d__2, d__3, d__4;
    doublecomplex z__1;

    /* Builtin functions */
    double d_imag(doublecomplex *);

    /* Local variables */
    integer i__, j, k;
    doublereal s, xk;
    integer nz;
    doublereal eps;
    integer kase;
    doublereal safe1, safe2;
    extern logical lsame_(char *, char *);
    integer isave[3], count;
    logical upper;
    extern /* Subroutine */ int zcopy_(integer *, doublecomplex *, integer *, 
	    doublecomplex *, integer *), zaxpy_(integer *, doublecomplex *, 
	    doublecomplex *, integer *, doublecomplex *, integer *), zsymv_(
	    char *, integer *, doublecomplex *, doublecomplex *, integer *, 
	    doublecomplex *, integer *, doublecomplex *, doublecomplex *, 
	    integer *), zlacn2_(integer *, doublecomplex *, 
	    doublecomplex *, doublereal *, integer *, integer *);
    extern doublereal dlamch_(char *);
    doublereal safmin;
    extern /* Subroutine */ int xerbla_(char *, integer *);
    doublereal lstres;
    extern /* Subroutine */ int zsytrs_(char *, integer *, integer *, 
	    doublecomplex *, integer *, integer *, doublecomplex *, integer *, 
	     integer *);


/*  -- LAPACK routine (version 3.2) -- */
/*     Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */
/*     November 2006 */

/*     Modified to call ZLACN2 in place of ZLACON, 10 Feb 03, SJH. */

/*     .. Scalar Arguments .. */
/*     .. */
/*     .. Array Arguments .. */
/*     .. */

/*  Purpose */
/*  ======= */

/*  ZSYRFS improves the computed solution to a system of linear */
/*  equations when the coefficient matrix is symmetric indefinite, and */
/*  provides error bounds and backward error estimates for the solution. */

/*  Arguments */
/*  ========= */

/*  UPLO    (input) CHARACTER*1 */
/*          = 'U':  Upper triangle of A is stored; */
/*          = 'L':  Lower triangle of A is stored. */

/*  N       (input) INTEGER */
/*          The order of the matrix A.  N >= 0. */

/*  NRHS    (input) INTEGER */
/*          The number of right hand sides, i.e., the number of columns */
/*          of the matrices B and X.  NRHS >= 0. */

/*  A       (input) COMPLEX*16 array, dimension (LDA,N) */
/*          The symmetric matrix A.  If UPLO = 'U', the leading N-by-N */
/*          upper triangular part of A contains the upper triangular part */
/*          of the matrix A, and the strictly lower triangular part of A */
/*          is not referenced.  If UPLO = 'L', the leading N-by-N lower */
/*          triangular part of A contains the lower triangular part of */
/*          the matrix A, and the strictly upper triangular part of A is */
/*          not referenced. */

/*  LDA     (input) INTEGER */
/*          The leading dimension of the array A.  LDA >= max(1,N). */

/*  AF      (input) COMPLEX*16 array, dimension (LDAF,N) */
/*          The factored form of the matrix A.  AF contains the block */
/*          diagonal matrix D and the multipliers used to obtain the */
/*          factor U or L from the factorization A = U*D*U**T or */
/*          A = L*D*L**T as computed by ZSYTRF. */

/*  LDAF    (input) INTEGER */
/*          The leading dimension of the array AF.  LDAF >= max(1,N). */

/*  IPIV    (input) INTEGER array, dimension (N) */
/*          Details of the interchanges and the block structure of D */
/*          as determined by ZSYTRF. */

/*  B       (input) COMPLEX*16 array, dimension (LDB,NRHS) */
/*          The right hand side matrix B. */

/*  LDB     (input) INTEGER */
/*          The leading dimension of the array B.  LDB >= max(1,N). */

/*  X       (input/output) COMPLEX*16 array, dimension (LDX,NRHS) */
/*          On entry, the solution matrix X, as computed by ZSYTRS. */
/*          On exit, the improved solution matrix X. */

/*  LDX     (input) INTEGER */
/*          The leading dimension of the array X.  LDX >= max(1,N). */

/*  FERR    (output) DOUBLE PRECISION array, dimension (NRHS) */
/*          The estimated forward error bound for each solution vector */
/*          X(j) (the j-th column of the solution matrix X). */
/*          If XTRUE is the true solution corresponding to X(j), FERR(j) */
/*          is an estimated upper bound for the magnitude of the largest */
/*          element in (X(j) - XTRUE) divided by the magnitude of the */
/*          largest element in X(j).  The estimate is as reliable as */
/*          the estimate for RCOND, and is almost always a slight */
/*          overestimate of the true error. */

/*  BERR    (output) DOUBLE PRECISION array, dimension (NRHS) */
/*          The componentwise relative backward error of each solution */
/*          vector X(j) (i.e., the smallest relative change in */
/*          any element of A or B that makes X(j) an exact solution). */

/*  WORK    (workspace) COMPLEX*16 array, dimension (2*N) */

/*  RWORK   (workspace) DOUBLE PRECISION array, dimension (N) */

/*  INFO    (output) INTEGER */
/*          = 0:  successful exit */
/*          < 0:  if INFO = -i, the i-th argument had an illegal value */

/*  Internal Parameters */
/*  =================== */

/*  ITMAX is the maximum number of steps of iterative refinement. */

/*  ===================================================================== */

/*     .. Parameters .. */
/*     .. */
/*     .. Local Scalars .. */
/*     .. */
/*     .. Local Arrays .. */
/*     .. */
/*     .. External Subroutines .. */
/*     .. */
/*     .. Intrinsic Functions .. */
/*     .. */
/*     .. External Functions .. */
/*     .. */
/*     .. Statement Functions .. */
/*     .. */
/*     .. Statement Function definitions .. */
/*     .. */
/*     .. Executable Statements .. */

/*     Test the input parameters. */

    /* Parameter adjustments */
    a_dim1 = *lda;
    a_offset = 1 + a_dim1;
    a -= a_offset;
    af_dim1 = *ldaf;
    af_offset = 1 + af_dim1;
    af -= af_offset;
    --ipiv;
    b_dim1 = *ldb;
    b_offset = 1 + b_dim1;
    b -= b_offset;
    x_dim1 = *ldx;
    x_offset = 1 + x_dim1;
    x -= x_offset;
    --ferr;
    --berr;
    --work;
    --rwork;

    /* Function Body */
    *info = 0;
    upper = lsame_(uplo, "U");
    if (! upper && ! lsame_(uplo, "L")) {
	*info = -1;
    } else if (*n < 0) {
	*info = -2;
    } else if (*nrhs < 0) {
	*info = -3;
    } else if (*lda < max(1,*n)) {
	*info = -5;
    } else if (*ldaf < max(1,*n)) {
	*info = -7;
    } else if (*ldb < max(1,*n)) {
	*info = -10;
    } else if (*ldx < max(1,*n)) {
	*info = -12;
    }
    if (*info != 0) {
	i__1 = -(*info);
	xerbla_("ZSYRFS", &i__1);
	return 0;
    }

/*     Quick return if possible */

    if (*n == 0 || *nrhs == 0) {
	i__1 = *nrhs;
	for (j = 1; j <= i__1; ++j) {
	    ferr[j] = 0.;
	    berr[j] = 0.;
/* L10: */
	}
	return 0;
    }

/*     NZ = maximum number of nonzero elements in each row of A, plus 1 */

    nz = *n + 1;
    eps = dlamch_("Epsilon");
    safmin = dlamch_("Safe minimum");
    safe1 = nz * safmin;
    safe2 = safe1 / eps;

/*     Do for each right hand side */

    i__1 = *nrhs;
    for (j = 1; j <= i__1; ++j) {

	count = 1;
	lstres = 3.;
L20:

/*        Loop until stopping criterion is satisfied. */

/*        Compute residual R = B - A * X */

	zcopy_(n, &b[j * b_dim1 + 1], &c__1, &work[1], &c__1);
	z__1.r = -1., z__1.i = -0.;
	zsymv_(uplo, n, &z__1, &a[a_offset], lda, &x[j * x_dim1 + 1], &c__1, &
		c_b1, &work[1], &c__1);

/*        Compute componentwise relative backward error from formula */

/*        max(i) ( abs(R(i)) / ( abs(A)*abs(X) + abs(B) )(i) ) */

/*        where abs(Z) is the componentwise absolute value of the matrix */
/*        or vector Z.  If the i-th component of the denominator is less */
/*        than SAFE2, then SAFE1 is added to the i-th components of the */
/*        numerator and denominator before dividing. */

	i__2 = *n;
	for (i__ = 1; i__ <= i__2; ++i__) {
	    i__3 = i__ + j * b_dim1;
	    rwork[i__] = (d__1 = b[i__3].r, abs(d__1)) + (d__2 = d_imag(&b[
		    i__ + j * b_dim1]), abs(d__2));
/* L30: */
	}

/*        Compute abs(A)*abs(X) + abs(B). */

	if (upper) {
	    i__2 = *n;
	    for (k = 1; k <= i__2; ++k) {
		s = 0.;
		i__3 = k + j * x_dim1;
		xk = (d__1 = x[i__3].r, abs(d__1)) + (d__2 = d_imag(&x[k + j *
			 x_dim1]), abs(d__2));
		i__3 = k - 1;
		for (i__ = 1; i__ <= i__3; ++i__) {
		    i__4 = i__ + k * a_dim1;
		    rwork[i__] += ((d__1 = a[i__4].r, abs(d__1)) + (d__2 = 
			    d_imag(&a[i__ + k * a_dim1]), abs(d__2))) * xk;
		    i__4 = i__ + k * a_dim1;
		    i__5 = i__ + j * x_dim1;
		    s += ((d__1 = a[i__4].r, abs(d__1)) + (d__2 = d_imag(&a[
			    i__ + k * a_dim1]), abs(d__2))) * ((d__3 = x[i__5]
			    .r, abs(d__3)) + (d__4 = d_imag(&x[i__ + j * 
			    x_dim1]), abs(d__4)));
/* L40: */
		}
		i__3 = k + k * a_dim1;
		rwork[k] = rwork[k] + ((d__1 = a[i__3].r, abs(d__1)) + (d__2 =
			 d_imag(&a[k + k * a_dim1]), abs(d__2))) * xk + s;
/* L50: */
	    }
	} else {
	    i__2 = *n;
	    for (k = 1; k <= i__2; ++k) {
		s = 0.;
		i__3 = k + j * x_dim1;
		xk = (d__1 = x[i__3].r, abs(d__1)) + (d__2 = d_imag(&x[k + j *
			 x_dim1]), abs(d__2));
		i__3 = k + k * a_dim1;
		rwork[k] += ((d__1 = a[i__3].r, abs(d__1)) + (d__2 = d_imag(&
			a[k + k * a_dim1]), abs(d__2))) * xk;
		i__3 = *n;
		for (i__ = k + 1; i__ <= i__3; ++i__) {
		    i__4 = i__ + k * a_dim1;
		    rwork[i__] += ((d__1 = a[i__4].r, abs(d__1)) + (d__2 = 
			    d_imag(&a[i__ + k * a_dim1]), abs(d__2))) * xk;
		    i__4 = i__ + k * a_dim1;
		    i__5 = i__ + j * x_dim1;
		    s += ((d__1 = a[i__4].r, abs(d__1)) + (d__2 = d_imag(&a[
			    i__ + k * a_dim1]), abs(d__2))) * ((d__3 = x[i__5]
			    .r, abs(d__3)) + (d__4 = d_imag(&x[i__ + j * 
			    x_dim1]), abs(d__4)));
/* L60: */
		}
		rwork[k] += s;
/* L70: */
	    }
	}
	s = 0.;
	i__2 = *n;
	for (i__ = 1; i__ <= i__2; ++i__) {
	    if (rwork[i__] > safe2) {
/* Computing MAX */
		i__3 = i__;
		d__3 = s, d__4 = ((d__1 = work[i__3].r, abs(d__1)) + (d__2 = 
			d_imag(&work[i__]), abs(d__2))) / rwork[i__];
		s = max(d__3,d__4);
	    } else {
/* Computing MAX */
		i__3 = i__;
		d__3 = s, d__4 = ((d__1 = work[i__3].r, abs(d__1)) + (d__2 = 
			d_imag(&work[i__]), abs(d__2)) + safe1) / (rwork[i__] 
			+ safe1);
		s = max(d__3,d__4);
	    }
/* L80: */
	}
	berr[j] = s;

/*        Test stopping criterion. Continue iterating if */
/*           1) The residual BERR(J) is larger than machine epsilon, and */
/*           2) BERR(J) decreased by at least a factor of 2 during the */
/*              last iteration, and */
/*           3) At most ITMAX iterations tried. */

	if (berr[j] > eps && berr[j] * 2. <= lstres && count <= 5) {

/*           Update solution and try again. */

	    zsytrs_(uplo, n, &c__1, &af[af_offset], ldaf, &ipiv[1], &work[1], 
		    n, info);
	    zaxpy_(n, &c_b1, &work[1], &c__1, &x[j * x_dim1 + 1], &c__1);
	    lstres = berr[j];
	    ++count;
	    goto L20;
	}

/*        Bound error from formula */

/*        norm(X - XTRUE) / norm(X) .le. FERR = */
/*        norm( abs(inv(A))* */
/*           ( abs(R) + NZ*EPS*( abs(A)*abs(X)+abs(B) ))) / norm(X) */

/*        where */
/*          norm(Z) is the magnitude of the largest component of Z */
/*          inv(A) is the inverse of A */
/*          abs(Z) is the componentwise absolute value of the matrix or */
/*             vector Z */
/*          NZ is the maximum number of nonzeros in any row of A, plus 1 */
/*          EPS is machine epsilon */

/*        The i-th component of abs(R)+NZ*EPS*(abs(A)*abs(X)+abs(B)) */
/*        is incremented by SAFE1 if the i-th component of */
/*        abs(A)*abs(X) + abs(B) is less than SAFE2. */

/*        Use ZLACN2 to estimate the infinity-norm of the matrix */
/*           inv(A) * diag(W), */
/*        where W = abs(R) + NZ*EPS*( abs(A)*abs(X)+abs(B) ))) */

	i__2 = *n;
	for (i__ = 1; i__ <= i__2; ++i__) {
	    if (rwork[i__] > safe2) {
		i__3 = i__;
		rwork[i__] = (d__1 = work[i__3].r, abs(d__1)) + (d__2 = 
			d_imag(&work[i__]), abs(d__2)) + nz * eps * rwork[i__]
			;
	    } else {
		i__3 = i__;
		rwork[i__] = (d__1 = work[i__3].r, abs(d__1)) + (d__2 = 
			d_imag(&work[i__]), abs(d__2)) + nz * eps * rwork[i__]
			 + safe1;
	    }
/* L90: */
	}

	kase = 0;
L100:
	zlacn2_(n, &work[*n + 1], &work[1], &ferr[j], &kase, isave);
	if (kase != 0) {
	    if (kase == 1) {

/*              Multiply by diag(W)*inv(A'). */

		zsytrs_(uplo, n, &c__1, &af[af_offset], ldaf, &ipiv[1], &work[
			1], n, info);
		i__2 = *n;
		for (i__ = 1; i__ <= i__2; ++i__) {
		    i__3 = i__;
		    i__4 = i__;
		    i__5 = i__;
		    z__1.r = rwork[i__4] * work[i__5].r, z__1.i = rwork[i__4] 
			    * work[i__5].i;
		    work[i__3].r = z__1.r, work[i__3].i = z__1.i;
/* L110: */
		}
	    } else if (kase == 2) {

/*              Multiply by inv(A)*diag(W). */

		i__2 = *n;
		for (i__ = 1; i__ <= i__2; ++i__) {
		    i__3 = i__;
		    i__4 = i__;
		    i__5 = i__;
		    z__1.r = rwork[i__4] * work[i__5].r, z__1.i = rwork[i__4] 
			    * work[i__5].i;
		    work[i__3].r = z__1.r, work[i__3].i = z__1.i;
/* L120: */
		}
		zsytrs_(uplo, n, &c__1, &af[af_offset], ldaf, &ipiv[1], &work[
			1], n, info);
	    }
	    goto L100;
	}

/*        Normalize error. */

	lstres = 0.;
	i__2 = *n;
	for (i__ = 1; i__ <= i__2; ++i__) {
/* Computing MAX */
	    i__3 = i__ + j * x_dim1;
	    d__3 = lstres, d__4 = (d__1 = x[i__3].r, abs(d__1)) + (d__2 = 
		    d_imag(&x[i__ + j * x_dim1]), abs(d__2));
	    lstres = max(d__3,d__4);
/* L130: */
	}
	if (lstres != 0.) {
	    ferr[j] /= lstres;
	}

/* L140: */
    }

    return 0;

/*     End of ZSYRFS */

} /* zsyrfs_ */
Esempio n. 3
0
/* Subroutine */ int zsysv_(char *uplo, integer *n, integer *nrhs, 
	doublecomplex *a, integer *lda, integer *ipiv, doublecomplex *b, 
	integer *ldb, doublecomplex *work, integer *lwork, integer *info)
{
    /* System generated locals */
    integer a_dim1, a_offset, b_dim1, b_offset, i__1;

    /* Local variables */
    integer nb;
    extern logical lsame_(char *, char *);
    extern /* Subroutine */ int xerbla_(char *, integer *);
    extern integer ilaenv_(integer *, char *, char *, integer *, integer *, 
	    integer *, integer *);
    integer lwkopt;
    logical lquery;
    extern /* Subroutine */ int zsytrf_(char *, integer *, doublecomplex *, 
	    integer *, integer *, doublecomplex *, integer *, integer *), zsytrs_(char *, integer *, integer *, doublecomplex *, 
	    integer *, integer *, doublecomplex *, integer *, integer *);


/*  -- LAPACK driver routine (version 3.2) -- */
/*     Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */
/*     November 2006 */

/*     .. Scalar Arguments .. */
/*     .. */
/*     .. Array Arguments .. */
/*     .. */

/*  Purpose */
/*  ======= */

/*  ZSYSV computes the solution to a complex system of linear equations */
/*     A * X = B, */
/*  where A is an N-by-N symmetric matrix and X and B are N-by-NRHS */
/*  matrices. */

/*  The diagonal pivoting method is used to factor A as */
/*     A = U * D * U**T,  if UPLO = 'U', or */
/*     A = L * D * L**T,  if UPLO = 'L', */
/*  where U (or L) is a product of permutation and unit upper (lower) */
/*  triangular matrices, and D is symmetric and block diagonal with */
/*  1-by-1 and 2-by-2 diagonal blocks.  The factored form of A is then */
/*  used to solve the system of equations A * X = B. */

/*  Arguments */
/*  ========= */

/*  UPLO    (input) CHARACTER*1 */
/*          = 'U':  Upper triangle of A is stored; */
/*          = 'L':  Lower triangle of A is stored. */

/*  N       (input) INTEGER */
/*          The number of linear equations, i.e., the order of the */
/*          matrix A.  N >= 0. */

/*  NRHS    (input) INTEGER */
/*          The number of right hand sides, i.e., the number of columns */
/*          of the matrix B.  NRHS >= 0. */

/*  A       (input/output) COMPLEX*16 array, dimension (LDA,N) */
/*          On entry, the symmetric matrix A.  If UPLO = 'U', the leading */
/*          N-by-N upper triangular part of A contains the upper */
/*          triangular part of the matrix A, and the strictly lower */
/*          triangular part of A is not referenced.  If UPLO = 'L', the */
/*          leading N-by-N lower triangular part of A contains the lower */
/*          triangular part of the matrix A, and the strictly upper */
/*          triangular part of A is not referenced. */

/*          On exit, if INFO = 0, the block diagonal matrix D and the */
/*          multipliers used to obtain the factor U or L from the */
/*          factorization A = U*D*U**T or A = L*D*L**T as computed by */
/*          ZSYTRF. */

/*  LDA     (input) INTEGER */
/*          The leading dimension of the array A.  LDA >= max(1,N). */

/*  IPIV    (output) INTEGER array, dimension (N) */
/*          Details of the interchanges and the block structure of D, as */
/*          determined by ZSYTRF.  If IPIV(k) > 0, then rows and columns */
/*          k and IPIV(k) were interchanged, and D(k,k) is a 1-by-1 */
/*          diagonal block.  If UPLO = 'U' and IPIV(k) = IPIV(k-1) < 0, */
/*          then rows and columns k-1 and -IPIV(k) were interchanged and */
/*          D(k-1:k,k-1:k) is a 2-by-2 diagonal block.  If UPLO = 'L' and */
/*          IPIV(k) = IPIV(k+1) < 0, then rows and columns k+1 and */
/*          -IPIV(k) were interchanged and D(k:k+1,k:k+1) is a 2-by-2 */
/*          diagonal block. */

/*  B       (input/output) COMPLEX*16 array, dimension (LDB,NRHS) */
/*          On entry, the N-by-NRHS right hand side matrix B. */
/*          On exit, if INFO = 0, the N-by-NRHS solution matrix X. */

/*  LDB     (input) INTEGER */
/*          The leading dimension of the array B.  LDB >= max(1,N). */

/*  WORK    (workspace/output) COMPLEX*16 array, dimension (MAX(1,LWORK)) */
/*          On exit, if INFO = 0, WORK(1) returns the optimal LWORK. */

/*  LWORK   (input) INTEGER */
/*          The length of WORK.  LWORK >= 1, and for best performance */
/*          LWORK >= max(1,N*NB), where NB is the optimal blocksize for */
/*          ZSYTRF. */

/*          If LWORK = -1, then a workspace query is assumed; the routine */
/*          only calculates the optimal size of the WORK array, returns */
/*          this value as the first entry of the WORK array, and no error */
/*          message related to LWORK is issued by XERBLA. */

/*  INFO    (output) INTEGER */
/*          = 0: successful exit */
/*          < 0: if INFO = -i, the i-th argument had an illegal value */
/*          > 0: if INFO = i, D(i,i) is exactly zero.  The factorization */
/*               has been completed, but the block diagonal matrix D is */
/*               exactly singular, so the solution could not be computed. */

/*  ===================================================================== */

/*     .. Local Scalars .. */
/*     .. */
/*     .. External Functions .. */
/*     .. */
/*     .. External Subroutines .. */
/*     .. */
/*     .. Intrinsic Functions .. */
/*     .. */
/*     .. Executable Statements .. */

/*     Test the input parameters. */

    /* Parameter adjustments */
    a_dim1 = *lda;
    a_offset = 1 + a_dim1;
    a -= a_offset;
    --ipiv;
    b_dim1 = *ldb;
    b_offset = 1 + b_dim1;
    b -= b_offset;
    --work;

    /* Function Body */
    *info = 0;
    lquery = *lwork == -1;
    if (! lsame_(uplo, "U") && ! lsame_(uplo, "L")) {
	*info = -1;
    } else if (*n < 0) {
	*info = -2;
    } else if (*nrhs < 0) {
	*info = -3;
    } else if (*lda < max(1,*n)) {
	*info = -5;
    } else if (*ldb < max(1,*n)) {
	*info = -8;
    } else if (*lwork < 1 && ! lquery) {
	*info = -10;
    }

    if (*info == 0) {
	if (*n == 0) {
	    lwkopt = 1;
	} else {
	    nb = ilaenv_(&c__1, "ZSYTRF", uplo, n, &c_n1, &c_n1, &c_n1);
	    lwkopt = *n * nb;
	}
	work[1].r = (doublereal) lwkopt, work[1].i = 0.;
    }

    if (*info != 0) {
	i__1 = -(*info);
	xerbla_("ZSYSV ", &i__1);
	return 0;
    } else if (lquery) {
	return 0;
    }

/*     Compute the factorization A = U*D*U' or A = L*D*L'. */

    zsytrf_(uplo, n, &a[a_offset], lda, &ipiv[1], &work[1], lwork, info);
    if (*info == 0) {

/*        Solve the system A*X = B, overwriting B with X. */

	zsytrs_(uplo, n, nrhs, &a[a_offset], lda, &ipiv[1], &b[b_offset], ldb, 
		 info);

    }

    work[1].r = (doublereal) lwkopt, work[1].i = 0.;

    return 0;

/*     End of ZSYSV */

} /* zsysv_ */
Esempio n. 4
0
/* Subroutine */ int zerrsy_(char *path, integer *nunit)
{
    /* System generated locals */
    integer i__1;
    doublereal d__1, d__2;
    doublecomplex z__1;

    /* Builtin functions */
    integer s_wsle(cilist *), e_wsle(void);
    /* Subroutine */ int s_copy(char *, char *, ftnlen, ftnlen);

    /* Local variables */
    doublecomplex a[16]	/* was [4][4] */, b[4];
    integer i__, j;
    doublereal r__[4];
    doublecomplex w[8], x[4];
    char c2[2];
    doublereal r1[4], r2[4];
    doublecomplex af[16]	/* was [4][4] */;
    integer ip[4], info;
    doublereal anrm, rcond;
    extern /* Subroutine */ int zsytf2_(char *, integer *, doublecomplex *, 
	    integer *, integer *, integer *), alaesm_(char *, logical 
	    *, integer *);
    extern logical lsamen_(integer *, char *, char *);
    extern /* Subroutine */ int chkxer_(char *, integer *, integer *, logical 
	    *, logical *), zspcon_(char *, integer *, doublecomplex *, 
	     integer *, doublereal *, doublereal *, doublecomplex *, integer *
), zsycon_(char *, integer *, doublecomplex *, integer *, 
	    integer *, doublereal *, doublereal *, doublecomplex *, integer *), zsprfs_(char *, integer *, integer *, doublecomplex *, 
	    doublecomplex *, integer *, doublecomplex *, integer *, 
	    doublecomplex *, integer *, doublereal *, doublereal *, 
	    doublecomplex *, doublereal *, integer *), zsptrf_(char *, 
	     integer *, doublecomplex *, integer *, integer *), 
	    zsptri_(char *, integer *, doublecomplex *, integer *, 
	    doublecomplex *, integer *), zsyrfs_(char *, integer *, 
	    integer *, doublecomplex *, integer *, doublecomplex *, integer *, 
	     integer *, doublecomplex *, integer *, doublecomplex *, integer *
, doublereal *, doublereal *, doublecomplex *, doublereal *, 
	    integer *), zsytrf_(char *, integer *, doublecomplex *, 
	    integer *, integer *, doublecomplex *, integer *, integer *), zsytri_(char *, integer *, doublecomplex *, integer *, 
	    integer *, doublecomplex *, integer *), zsptrs_(char *, 
	    integer *, integer *, doublecomplex *, integer *, doublecomplex *, 
	     integer *, integer *), zsytrs_(char *, integer *, 
	    integer *, doublecomplex *, integer *, integer *, doublecomplex *, 
	     integer *, integer *);

    /* Fortran I/O blocks */
    static cilist io___1 = { 0, 0, 0, 0, 0 };



/*  -- LAPACK test routine (version 3.1) -- */
/*     Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */
/*     November 2006 */

/*     .. Scalar Arguments .. */
/*     .. */

/*  Purpose */
/*  ======= */

/*  ZERRSY tests the error exits for the COMPLEX*16 routines */
/*  for symmetric indefinite matrices. */

/*  Arguments */
/*  ========= */

/*  PATH    (input) CHARACTER*3 */
/*          The LAPACK path name for the routines to be tested. */

/*  NUNIT   (input) INTEGER */
/*          The unit number for output. */

/*  ===================================================================== */

/*     .. Parameters .. */
/*     .. */
/*     .. Local Scalars .. */
/*     .. */
/*     .. Local Arrays .. */
/*     .. */
/*     .. External Functions .. */
/*     .. */
/*     .. External Subroutines .. */
/*     .. */
/*     .. Scalars in Common .. */
/*     .. */
/*     .. Common blocks .. */
/*     .. */
/*     .. Intrinsic Functions .. */
/*     .. */
/*     .. Executable Statements .. */

    infoc_1.nout = *nunit;
    io___1.ciunit = infoc_1.nout;
    s_wsle(&io___1);
    e_wsle();
    s_copy(c2, path + 1, (ftnlen)2, (ftnlen)2);

/*     Set the variables to innocuous values. */

    for (j = 1; j <= 4; ++j) {
	for (i__ = 1; i__ <= 4; ++i__) {
	    i__1 = i__ + (j << 2) - 5;
	    d__1 = 1. / (doublereal) (i__ + j);
	    d__2 = -1. / (doublereal) (i__ + j);
	    z__1.r = d__1, z__1.i = d__2;
	    a[i__1].r = z__1.r, a[i__1].i = z__1.i;
	    i__1 = i__ + (j << 2) - 5;
	    d__1 = 1. / (doublereal) (i__ + j);
	    d__2 = -1. / (doublereal) (i__ + j);
	    z__1.r = d__1, z__1.i = d__2;
	    af[i__1].r = z__1.r, af[i__1].i = z__1.i;
/* L10: */
	}
	i__1 = j - 1;
	b[i__1].r = 0., b[i__1].i = 0.;
	r1[j - 1] = 0.;
	r2[j - 1] = 0.;
	i__1 = j - 1;
	w[i__1].r = 0., w[i__1].i = 0.;
	i__1 = j - 1;
	x[i__1].r = 0., x[i__1].i = 0.;
	ip[j - 1] = j;
/* L20: */
    }
    anrm = 1.;
    infoc_1.ok = TRUE_;

/*     Test error exits of the routines that use the diagonal pivoting */
/*     factorization of a symmetric indefinite matrix. */

    if (lsamen_(&c__2, c2, "SY")) {

/*        ZSYTRF */

	s_copy(srnamc_1.srnamt, "ZSYTRF", (ftnlen)6, (ftnlen)6);
	infoc_1.infot = 1;
	zsytrf_("/", &c__0, a, &c__1, ip, w, &c__1, &info);
	chkxer_("ZSYTRF", &infoc_1.infot, &infoc_1.nout, &infoc_1.lerr, &
		infoc_1.ok);
	infoc_1.infot = 2;
	zsytrf_("U", &c_n1, a, &c__1, ip, w, &c__1, &info);
	chkxer_("ZSYTRF", &infoc_1.infot, &infoc_1.nout, &infoc_1.lerr, &
		infoc_1.ok);
	infoc_1.infot = 4;
	zsytrf_("U", &c__2, a, &c__1, ip, w, &c__4, &info);
	chkxer_("ZSYTRF", &infoc_1.infot, &infoc_1.nout, &infoc_1.lerr, &
		infoc_1.ok);

/*        ZSYTF2 */

	s_copy(srnamc_1.srnamt, "ZSYTF2", (ftnlen)6, (ftnlen)6);
	infoc_1.infot = 1;
	zsytf2_("/", &c__0, a, &c__1, ip, &info);
	chkxer_("ZSYTF2", &infoc_1.infot, &infoc_1.nout, &infoc_1.lerr, &
		infoc_1.ok);
	infoc_1.infot = 2;
	zsytf2_("U", &c_n1, a, &c__1, ip, &info);
	chkxer_("ZSYTF2", &infoc_1.infot, &infoc_1.nout, &infoc_1.lerr, &
		infoc_1.ok);
	infoc_1.infot = 4;
	zsytf2_("U", &c__2, a, &c__1, ip, &info);
	chkxer_("ZSYTF2", &infoc_1.infot, &infoc_1.nout, &infoc_1.lerr, &
		infoc_1.ok);

/*        ZSYTRI */

	s_copy(srnamc_1.srnamt, "ZSYTRI", (ftnlen)6, (ftnlen)6);
	infoc_1.infot = 1;
	zsytri_("/", &c__0, a, &c__1, ip, w, &info);
	chkxer_("ZSYTRI", &infoc_1.infot, &infoc_1.nout, &infoc_1.lerr, &
		infoc_1.ok);
	infoc_1.infot = 2;
	zsytri_("U", &c_n1, a, &c__1, ip, w, &info);
	chkxer_("ZSYTRI", &infoc_1.infot, &infoc_1.nout, &infoc_1.lerr, &
		infoc_1.ok);
	infoc_1.infot = 4;
	zsytri_("U", &c__2, a, &c__1, ip, w, &info);
	chkxer_("ZSYTRI", &infoc_1.infot, &infoc_1.nout, &infoc_1.lerr, &
		infoc_1.ok);

/*        ZSYTRS */

	s_copy(srnamc_1.srnamt, "ZSYTRS", (ftnlen)6, (ftnlen)6);
	infoc_1.infot = 1;
	zsytrs_("/", &c__0, &c__0, a, &c__1, ip, b, &c__1, &info);
	chkxer_("ZSYTRS", &infoc_1.infot, &infoc_1.nout, &infoc_1.lerr, &
		infoc_1.ok);
	infoc_1.infot = 2;
	zsytrs_("U", &c_n1, &c__0, a, &c__1, ip, b, &c__1, &info);
	chkxer_("ZSYTRS", &infoc_1.infot, &infoc_1.nout, &infoc_1.lerr, &
		infoc_1.ok);
	infoc_1.infot = 3;
	zsytrs_("U", &c__0, &c_n1, a, &c__1, ip, b, &c__1, &info);
	chkxer_("ZSYTRS", &infoc_1.infot, &infoc_1.nout, &infoc_1.lerr, &
		infoc_1.ok);
	infoc_1.infot = 5;
	zsytrs_("U", &c__2, &c__1, a, &c__1, ip, b, &c__2, &info);
	chkxer_("ZSYTRS", &infoc_1.infot, &infoc_1.nout, &infoc_1.lerr, &
		infoc_1.ok);
	infoc_1.infot = 8;
	zsytrs_("U", &c__2, &c__1, a, &c__2, ip, b, &c__1, &info);
	chkxer_("ZSYTRS", &infoc_1.infot, &infoc_1.nout, &infoc_1.lerr, &
		infoc_1.ok);

/*        ZSYRFS */

	s_copy(srnamc_1.srnamt, "ZSYRFS", (ftnlen)6, (ftnlen)6);
	infoc_1.infot = 1;
	zsyrfs_("/", &c__0, &c__0, a, &c__1, af, &c__1, ip, b, &c__1, x, &
		c__1, r1, r2, w, r__, &info);
	chkxer_("ZSYRFS", &infoc_1.infot, &infoc_1.nout, &infoc_1.lerr, &
		infoc_1.ok);
	infoc_1.infot = 2;
	zsyrfs_("U", &c_n1, &c__0, a, &c__1, af, &c__1, ip, b, &c__1, x, &
		c__1, r1, r2, w, r__, &info);
	chkxer_("ZSYRFS", &infoc_1.infot, &infoc_1.nout, &infoc_1.lerr, &
		infoc_1.ok);
	infoc_1.infot = 3;
	zsyrfs_("U", &c__0, &c_n1, a, &c__1, af, &c__1, ip, b, &c__1, x, &
		c__1, r1, r2, w, r__, &info);
	chkxer_("ZSYRFS", &infoc_1.infot, &infoc_1.nout, &infoc_1.lerr, &
		infoc_1.ok);
	infoc_1.infot = 5;
	zsyrfs_("U", &c__2, &c__1, a, &c__1, af, &c__2, ip, b, &c__2, x, &
		c__2, r1, r2, w, r__, &info);
	chkxer_("ZSYRFS", &infoc_1.infot, &infoc_1.nout, &infoc_1.lerr, &
		infoc_1.ok);
	infoc_1.infot = 7;
	zsyrfs_("U", &c__2, &c__1, a, &c__2, af, &c__1, ip, b, &c__2, x, &
		c__2, r1, r2, w, r__, &info);
	chkxer_("ZSYRFS", &infoc_1.infot, &infoc_1.nout, &infoc_1.lerr, &
		infoc_1.ok);
	infoc_1.infot = 10;
	zsyrfs_("U", &c__2, &c__1, a, &c__2, af, &c__2, ip, b, &c__1, x, &
		c__2, r1, r2, w, r__, &info);
	chkxer_("ZSYRFS", &infoc_1.infot, &infoc_1.nout, &infoc_1.lerr, &
		infoc_1.ok);
	infoc_1.infot = 12;
	zsyrfs_("U", &c__2, &c__1, a, &c__2, af, &c__2, ip, b, &c__2, x, &
		c__1, r1, r2, w, r__, &info);
	chkxer_("ZSYRFS", &infoc_1.infot, &infoc_1.nout, &infoc_1.lerr, &
		infoc_1.ok);

/*        ZSYCON */

	s_copy(srnamc_1.srnamt, "ZSYCON", (ftnlen)6, (ftnlen)6);
	infoc_1.infot = 1;
	zsycon_("/", &c__0, a, &c__1, ip, &anrm, &rcond, w, &info);
	chkxer_("ZSYCON", &infoc_1.infot, &infoc_1.nout, &infoc_1.lerr, &
		infoc_1.ok);
	infoc_1.infot = 2;
	zsycon_("U", &c_n1, a, &c__1, ip, &anrm, &rcond, w, &info);
	chkxer_("ZSYCON", &infoc_1.infot, &infoc_1.nout, &infoc_1.lerr, &
		infoc_1.ok);
	infoc_1.infot = 4;
	zsycon_("U", &c__2, a, &c__1, ip, &anrm, &rcond, w, &info);
	chkxer_("ZSYCON", &infoc_1.infot, &infoc_1.nout, &infoc_1.lerr, &
		infoc_1.ok);
	infoc_1.infot = 6;
	d__1 = -anrm;
	zsycon_("U", &c__1, a, &c__1, ip, &d__1, &rcond, w, &info);
	chkxer_("ZSYCON", &infoc_1.infot, &infoc_1.nout, &infoc_1.lerr, &
		infoc_1.ok);

/*     Test error exits of the routines that use the diagonal pivoting */
/*     factorization of a symmetric indefinite packed matrix. */

    } else if (lsamen_(&c__2, c2, "SP")) {

/*        ZSPTRF */

	s_copy(srnamc_1.srnamt, "ZSPTRF", (ftnlen)6, (ftnlen)6);
	infoc_1.infot = 1;
	zsptrf_("/", &c__0, a, ip, &info);
	chkxer_("ZSPTRF", &infoc_1.infot, &infoc_1.nout, &infoc_1.lerr, &
		infoc_1.ok);
	infoc_1.infot = 2;
	zsptrf_("U", &c_n1, a, ip, &info);
	chkxer_("ZSPTRF", &infoc_1.infot, &infoc_1.nout, &infoc_1.lerr, &
		infoc_1.ok);

/*        ZSPTRI */

	s_copy(srnamc_1.srnamt, "ZSPTRI", (ftnlen)6, (ftnlen)6);
	infoc_1.infot = 1;
	zsptri_("/", &c__0, a, ip, w, &info);
	chkxer_("ZSPTRI", &infoc_1.infot, &infoc_1.nout, &infoc_1.lerr, &
		infoc_1.ok);
	infoc_1.infot = 2;
	zsptri_("U", &c_n1, a, ip, w, &info);
	chkxer_("ZSPTRI", &infoc_1.infot, &infoc_1.nout, &infoc_1.lerr, &
		infoc_1.ok);

/*        ZSPTRS */

	s_copy(srnamc_1.srnamt, "ZSPTRS", (ftnlen)6, (ftnlen)6);
	infoc_1.infot = 1;
	zsptrs_("/", &c__0, &c__0, a, ip, b, &c__1, &info);
	chkxer_("ZSPTRS", &infoc_1.infot, &infoc_1.nout, &infoc_1.lerr, &
		infoc_1.ok);
	infoc_1.infot = 2;
	zsptrs_("U", &c_n1, &c__0, a, ip, b, &c__1, &info);
	chkxer_("ZSPTRS", &infoc_1.infot, &infoc_1.nout, &infoc_1.lerr, &
		infoc_1.ok);
	infoc_1.infot = 3;
	zsptrs_("U", &c__0, &c_n1, a, ip, b, &c__1, &info);
	chkxer_("ZSPTRS", &infoc_1.infot, &infoc_1.nout, &infoc_1.lerr, &
		infoc_1.ok);
	infoc_1.infot = 7;
	zsptrs_("U", &c__2, &c__1, a, ip, b, &c__1, &info);
	chkxer_("ZSPTRS", &infoc_1.infot, &infoc_1.nout, &infoc_1.lerr, &
		infoc_1.ok);

/*        ZSPRFS */

	s_copy(srnamc_1.srnamt, "ZSPRFS", (ftnlen)6, (ftnlen)6);
	infoc_1.infot = 1;
	zsprfs_("/", &c__0, &c__0, a, af, ip, b, &c__1, x, &c__1, r1, r2, w, 
		r__, &info);
	chkxer_("ZSPRFS", &infoc_1.infot, &infoc_1.nout, &infoc_1.lerr, &
		infoc_1.ok);
	infoc_1.infot = 2;
	zsprfs_("U", &c_n1, &c__0, a, af, ip, b, &c__1, x, &c__1, r1, r2, w, 
		r__, &info);
	chkxer_("ZSPRFS", &infoc_1.infot, &infoc_1.nout, &infoc_1.lerr, &
		infoc_1.ok);
	infoc_1.infot = 3;
	zsprfs_("U", &c__0, &c_n1, a, af, ip, b, &c__1, x, &c__1, r1, r2, w, 
		r__, &info);
	chkxer_("ZSPRFS", &infoc_1.infot, &infoc_1.nout, &infoc_1.lerr, &
		infoc_1.ok);
	infoc_1.infot = 8;
	zsprfs_("U", &c__2, &c__1, a, af, ip, b, &c__1, x, &c__2, r1, r2, w, 
		r__, &info);
	chkxer_("ZSPRFS", &infoc_1.infot, &infoc_1.nout, &infoc_1.lerr, &
		infoc_1.ok);
	infoc_1.infot = 10;
	zsprfs_("U", &c__2, &c__1, a, af, ip, b, &c__2, x, &c__1, r1, r2, w, 
		r__, &info);
	chkxer_("ZSPRFS", &infoc_1.infot, &infoc_1.nout, &infoc_1.lerr, &
		infoc_1.ok);

/*        ZSPCON */

	s_copy(srnamc_1.srnamt, "ZSPCON", (ftnlen)6, (ftnlen)6);
	infoc_1.infot = 1;
	zspcon_("/", &c__0, a, ip, &anrm, &rcond, w, &info);
	chkxer_("ZSPCON", &infoc_1.infot, &infoc_1.nout, &infoc_1.lerr, &
		infoc_1.ok);
	infoc_1.infot = 2;
	zspcon_("U", &c_n1, a, ip, &anrm, &rcond, w, &info);
	chkxer_("ZSPCON", &infoc_1.infot, &infoc_1.nout, &infoc_1.lerr, &
		infoc_1.ok);
	infoc_1.infot = 5;
	d__1 = -anrm;
	zspcon_("U", &c__1, a, ip, &d__1, &rcond, w, &info);
	chkxer_("ZSPCON", &infoc_1.infot, &infoc_1.nout, &infoc_1.lerr, &
		infoc_1.ok);
    }

/*     Print a summary line. */

    alaesm_(path, &infoc_1.ok, &infoc_1.nout);

    return 0;

/*     End of ZERRSY */

} /* zerrsy_ */
Esempio n. 5
0
/* Subroutine */ int zsycon_(char *uplo, integer *n, doublecomplex *a,
                             integer *lda, integer *ipiv, doublereal *anorm, doublereal *rcond,
                             doublecomplex *work, integer *info)
{
    /* System generated locals */
    integer a_dim1, a_offset, i__1, i__2;

    /* Local variables */
    integer i__, kase;
    integer isave[3];
    logical upper;
    doublereal ainvnm;

    /*  -- LAPACK routine (version 3.2) -- */
    /*     November 2006 */

    /*     Modified to call ZLACN2 in place of ZLACON, 10 Feb 03, SJH. */

    /*  Purpose */
    /*  ======= */

    /*  ZSYCON estimates the reciprocal of the condition number (in the */
    /*  1-norm) of a complex symmetric matrix A using the factorization */
    /*  A = U*D*U**T or A = L*D*L**T computed by ZSYTRF. */

    /*  An estimate is obtained for norm(inv(A)), and the reciprocal of the */
    /*  condition number is computed as RCOND = 1 / (ANORM * norm(inv(A))). */

    /*  Arguments */
    /*  ========= */

    /*  UPLO    (input) CHARACTER*1 */
    /*          Specifies whether the details of the factorization are stored */
    /*          as an upper or lower triangular matrix. */
    /*          = 'U':  Upper triangular, form is A = U*D*U**T; */
    /*          = 'L':  Lower triangular, form is A = L*D*L**T. */

    /*  N       (input) INTEGER */
    /*          The order of the matrix A.  N >= 0. */

    /*  A       (input) COMPLEX*16 array, dimension (LDA,N) */
    /*          The block diagonal matrix D and the multipliers used to */
    /*          obtain the factor U or L as computed by ZSYTRF. */

    /*  LDA     (input) INTEGER */
    /*          The leading dimension of the array A.  LDA >= max(1,N). */

    /*  IPIV    (input) INTEGER array, dimension (N) */
    /*          Details of the interchanges and the block structure of D */
    /*          as determined by ZSYTRF. */

    /*  ANORM   (input) DOUBLE PRECISION */
    /*          The 1-norm of the original matrix A. */

    /*  RCOND   (output) DOUBLE PRECISION */
    /*          The reciprocal of the condition number of the matrix A, */
    /*          computed as RCOND = 1/(ANORM * AINVNM), where AINVNM is an */
    /*          estimate of the 1-norm of inv(A) computed in this routine. */

    /*  WORK    (workspace) COMPLEX*16 array, dimension (2*N) */

    /*  INFO    (output) INTEGER */
    /*          = 0:  successful exit */
    /*          < 0:  if INFO = -i, the i-th argument had an illegal value */

    /*  ===================================================================== */

    /*     Test the input parameters. */

    /* Parameter adjustments */
    a_dim1 = *lda;
    a_offset = 1 + a_dim1;
    a -= a_offset;
    --ipiv;
    --work;

    /* Function Body */
    *info = 0;
    upper = lsame_(uplo, "U");
    if (! upper && ! lsame_(uplo, "L")) {
        *info = -1;
    } else if (*n < 0) {
        *info = -2;
    } else if (*lda < max(1,*n)) {
        *info = -4;
    } else if (*anorm < 0.) {
        *info = -6;
    }
    if (*info != 0) {
        i__1 = -(*info);
        xerbla_("ZSYCON", &i__1);
        return 0;
    }

    /*     Quick return if possible */

    *rcond = 0.;
    if (*n == 0) {
        *rcond = 1.;
        return 0;
    } else if (*anorm <= 0.) {
        return 0;
    }

    /*     Check that the diagonal matrix D is nonsingular. */

    if (upper) {

        /*        Upper triangular storage: examine D from bottom to top */

        for (i__ = *n; i__ >= 1; --i__) {
            i__1 = i__ + i__ * a_dim1;
            if (ipiv[i__] > 0 && (a[i__1].r == 0. && a[i__1].i == 0.)) {
                return 0;
            }
        }
    } else {

        /*        Lower triangular storage: examine D from top to bottom. */

        i__1 = *n;
        for (i__ = 1; i__ <= i__1; ++i__) {
            i__2 = i__ + i__ * a_dim1;
            if (ipiv[i__] > 0 && (a[i__2].r == 0. && a[i__2].i == 0.)) {
                return 0;
            }
        }
    }

    /*     Estimate the 1-norm of the inverse. */

    kase = 0;
L30:
    zlacn2_(n, &work[*n + 1], &work[1], &ainvnm, &kase, isave);
    if (kase != 0) {

        /*        Multiply by inv(L*D*L') or inv(U*D*U'). */

        zsytrs_(uplo, n, &c__1, &a[a_offset], lda, &ipiv[1], &work[1], n,
                info);
        goto L30;
    }

    /*     Compute the estimate of the reciprocal condition number. */

    if (ainvnm != 0.) {
        *rcond = 1. / ainvnm / *anorm;
    }

    return 0;

    /*     End of ZSYCON */

} /* zsycon_ */
Esempio n. 6
0
/* Subroutine */ int zsysvx_(char *fact, char *uplo, integer *n, integer *
	nrhs, doublecomplex *a, integer *lda, doublecomplex *af, integer *
	ldaf, integer *ipiv, doublecomplex *b, integer *ldb, doublecomplex *x, 
	 integer *ldx, doublereal *rcond, doublereal *ferr, doublereal *berr, 
	doublecomplex *work, integer *lwork, doublereal *rwork, integer *info)
{
    /* System generated locals */
    integer a_dim1, a_offset, af_dim1, af_offset, b_dim1, b_offset, x_dim1, 
	    x_offset, i__1, i__2;

    /* Local variables */
    integer nb;
    extern logical lsame_(char *, char *);
    doublereal anorm;
    extern doublereal dlamch_(char *);
    logical nofact;
    extern /* Subroutine */ int xerbla_(char *, integer *);
    extern integer ilaenv_(integer *, char *, char *, integer *, integer *, 
	    integer *, integer *);
    extern /* Subroutine */ int zlacpy_(char *, integer *, integer *, 
	    doublecomplex *, integer *, doublecomplex *, integer *);
    integer lwkopt;
    logical lquery;
    extern doublereal zlansy_(char *, char *, integer *, doublecomplex *, 
	    integer *, doublereal *);
    extern /* Subroutine */ int zsycon_(char *, integer *, doublecomplex *, 
	    integer *, integer *, doublereal *, doublereal *, doublecomplex *, 
	     integer *), zsyrfs_(char *, integer *, integer *, 
	    doublecomplex *, integer *, doublecomplex *, integer *, integer *, 
	     doublecomplex *, integer *, doublecomplex *, integer *, 
	    doublereal *, doublereal *, doublecomplex *, doublereal *, 
	    integer *), zsytrf_(char *, integer *, doublecomplex *, 
	    integer *, integer *, doublecomplex *, integer *, integer *), zsytrs_(char *, integer *, integer *, doublecomplex *, 
	    integer *, integer *, doublecomplex *, integer *, integer *);


/*  -- LAPACK driver routine (version 3.1) -- */
/*     Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */
/*     November 2006 */

/*     .. Scalar Arguments .. */
/*     .. */
/*     .. Array Arguments .. */
/*     .. */

/*  Purpose */
/*  ======= */

/*  ZSYSVX uses the diagonal pivoting factorization to compute the */
/*  solution to a complex system of linear equations A * X = B, */
/*  where A is an N-by-N symmetric matrix and X and B are N-by-NRHS */
/*  matrices. */

/*  Error bounds on the solution and a condition estimate are also */
/*  provided. */

/*  Description */
/*  =========== */

/*  The following steps are performed: */

/*  1. If FACT = 'N', the diagonal pivoting method is used to factor A. */
/*     The form of the factorization is */
/*        A = U * D * U**T,  if UPLO = 'U', or */
/*        A = L * D * L**T,  if UPLO = 'L', */
/*     where U (or L) is a product of permutation and unit upper (lower) */
/*     triangular matrices, and D is symmetric and block diagonal with */
/*     1-by-1 and 2-by-2 diagonal blocks. */

/*  2. If some D(i,i)=0, so that D is exactly singular, then the routine */
/*     returns with INFO = i. Otherwise, the factored form of A is used */
/*     to estimate the condition number of the matrix A.  If the */
/*     reciprocal of the condition number is less than machine precision, */
/*     INFO = N+1 is returned as a warning, but the routine still goes on */
/*     to solve for X and compute error bounds as described below. */

/*  3. The system of equations is solved for X using the factored form */
/*     of A. */

/*  4. Iterative refinement is applied to improve the computed solution */
/*     matrix and calculate error bounds and backward error estimates */
/*     for it. */

/*  Arguments */
/*  ========= */

/*  FACT    (input) CHARACTER*1 */
/*          Specifies whether or not the factored form of A has been */
/*          supplied on entry. */
/*          = 'F':  On entry, AF and IPIV contain the factored form */
/*                  of A.  A, AF and IPIV will not be modified. */
/*          = 'N':  The matrix A will be copied to AF and factored. */

/*  UPLO    (input) CHARACTER*1 */
/*          = 'U':  Upper triangle of A is stored; */
/*          = 'L':  Lower triangle of A is stored. */

/*  N       (input) INTEGER */
/*          The number of linear equations, i.e., the order of the */
/*          matrix A.  N >= 0. */

/*  NRHS    (input) INTEGER */
/*          The number of right hand sides, i.e., the number of columns */
/*          of the matrices B and X.  NRHS >= 0. */

/*  A       (input) COMPLEX*16 array, dimension (LDA,N) */
/*          The symmetric matrix A.  If UPLO = 'U', the leading N-by-N */
/*          upper triangular part of A contains the upper triangular part */
/*          of the matrix A, and the strictly lower triangular part of A */
/*          is not referenced.  If UPLO = 'L', the leading N-by-N lower */
/*          triangular part of A contains the lower triangular part of */
/*          the matrix A, and the strictly upper triangular part of A is */
/*          not referenced. */

/*  LDA     (input) INTEGER */
/*          The leading dimension of the array A.  LDA >= max(1,N). */

/*  AF      (input or output) COMPLEX*16 array, dimension (LDAF,N) */
/*          If FACT = 'F', then AF is an input argument and on entry */
/*          contains the block diagonal matrix D and the multipliers used */
/*          to obtain the factor U or L from the factorization */
/*          A = U*D*U**T or A = L*D*L**T as computed by ZSYTRF. */

/*          If FACT = 'N', then AF is an output argument and on exit */
/*          returns the block diagonal matrix D and the multipliers used */
/*          to obtain the factor U or L from the factorization */
/*          A = U*D*U**T or A = L*D*L**T. */

/*  LDAF    (input) INTEGER */
/*          The leading dimension of the array AF.  LDAF >= max(1,N). */

/*  IPIV    (input or output) INTEGER array, dimension (N) */
/*          If FACT = 'F', then IPIV is an input argument and on entry */
/*          contains details of the interchanges and the block structure */
/*          of D, as determined by ZSYTRF. */
/*          If IPIV(k) > 0, then rows and columns k and IPIV(k) were */
/*          interchanged and D(k,k) is a 1-by-1 diagonal block. */
/*          If UPLO = 'U' and IPIV(k) = IPIV(k-1) < 0, then rows and */
/*          columns k-1 and -IPIV(k) were interchanged and D(k-1:k,k-1:k) */
/*          is a 2-by-2 diagonal block.  If UPLO = 'L' and IPIV(k) = */
/*          IPIV(k+1) < 0, then rows and columns k+1 and -IPIV(k) were */
/*          interchanged and D(k:k+1,k:k+1) is a 2-by-2 diagonal block. */

/*          If FACT = 'N', then IPIV is an output argument and on exit */
/*          contains details of the interchanges and the block structure */
/*          of D, as determined by ZSYTRF. */

/*  B       (input) COMPLEX*16 array, dimension (LDB,NRHS) */
/*          The N-by-NRHS right hand side matrix B. */

/*  LDB     (input) INTEGER */
/*          The leading dimension of the array B.  LDB >= max(1,N). */

/*  X       (output) COMPLEX*16 array, dimension (LDX,NRHS) */
/*          If INFO = 0 or INFO = N+1, the N-by-NRHS solution matrix X. */

/*  LDX     (input) INTEGER */
/*          The leading dimension of the array X.  LDX >= max(1,N). */

/*  RCOND   (output) DOUBLE PRECISION */
/*          The estimate of the reciprocal condition number of the matrix */
/*          A.  If RCOND is less than the machine precision (in */
/*          particular, if RCOND = 0), the matrix is singular to working */
/*          precision.  This condition is indicated by a return code of */
/*          INFO > 0. */

/*  FERR    (output) DOUBLE PRECISION array, dimension (NRHS) */
/*          The estimated forward error bound for each solution vector */
/*          X(j) (the j-th column of the solution matrix X). */
/*          If XTRUE is the true solution corresponding to X(j), FERR(j) */
/*          is an estimated upper bound for the magnitude of the largest */
/*          element in (X(j) - XTRUE) divided by the magnitude of the */
/*          largest element in X(j).  The estimate is as reliable as */
/*          the estimate for RCOND, and is almost always a slight */
/*          overestimate of the true error. */

/*  BERR    (output) DOUBLE PRECISION array, dimension (NRHS) */
/*          The componentwise relative backward error of each solution */
/*          vector X(j) (i.e., the smallest relative change in */
/*          any element of A or B that makes X(j) an exact solution). */

/*  WORK    (workspace/output) COMPLEX*16 array, dimension (MAX(1,LWORK)) */
/*          On exit, if INFO = 0, WORK(1) returns the optimal LWORK. */

/*  LWORK   (input) INTEGER */
/*          The length of WORK.  LWORK >= max(1,2*N), and for best */
/*          performance, when FACT = 'N', LWORK >= max(1,2*N,N*NB), where */
/*          NB is the optimal blocksize for ZSYTRF. */

/*          If LWORK = -1, then a workspace query is assumed; the routine */
/*          only calculates the optimal size of the WORK array, returns */
/*          this value as the first entry of the WORK array, and no error */
/*          message related to LWORK is issued by XERBLA. */

/*  RWORK   (workspace) DOUBLE PRECISION array, dimension (N) */

/*  INFO    (output) INTEGER */
/*          = 0: successful exit */
/*          < 0: if INFO = -i, the i-th argument had an illegal value */
/*          > 0: if INFO = i, and i is */
/*                <= N:  D(i,i) is exactly zero.  The factorization */
/*                       has been completed but the factor D is exactly */
/*                       singular, so the solution and error bounds could */
/*                       not be computed. RCOND = 0 is returned. */
/*                = N+1: D is nonsingular, but RCOND is less than machine */
/*                       precision, meaning that the matrix is singular */
/*                       to working precision.  Nevertheless, the */
/*                       solution and error bounds are computed because */
/*                       there are a number of situations where the */
/*                       computed solution can be more accurate than the */
/*                       value of RCOND would suggest. */

/*  ===================================================================== */

/*     .. Parameters .. */
/*     .. */
/*     .. Local Scalars .. */
/*     .. */
/*     .. External Functions .. */
/*     .. */
/*     .. External Subroutines .. */
/*     .. */
/*     .. Intrinsic Functions .. */
/*     .. */
/*     .. Executable Statements .. */

/*     Test the input parameters. */

    /* Parameter adjustments */
    a_dim1 = *lda;
    a_offset = 1 + a_dim1;
    a -= a_offset;
    af_dim1 = *ldaf;
    af_offset = 1 + af_dim1;
    af -= af_offset;
    --ipiv;
    b_dim1 = *ldb;
    b_offset = 1 + b_dim1;
    b -= b_offset;
    x_dim1 = *ldx;
    x_offset = 1 + x_dim1;
    x -= x_offset;
    --ferr;
    --berr;
    --work;
    --rwork;

    /* Function Body */
    *info = 0;
    nofact = lsame_(fact, "N");
    lquery = *lwork == -1;
    if (! nofact && ! lsame_(fact, "F")) {
	*info = -1;
    } else if (! lsame_(uplo, "U") && ! lsame_(uplo, 
	    "L")) {
	*info = -2;
    } else if (*n < 0) {
	*info = -3;
    } else if (*nrhs < 0) {
	*info = -4;
    } else if (*lda < max(1,*n)) {
	*info = -6;
    } else if (*ldaf < max(1,*n)) {
	*info = -8;
    } else if (*ldb < max(1,*n)) {
	*info = -11;
    } else if (*ldx < max(1,*n)) {
	*info = -13;
    } else /* if(complicated condition) */ {
/* Computing MAX */
	i__1 = 1, i__2 = *n << 1;
	if (*lwork < max(i__1,i__2) && ! lquery) {
	    *info = -18;
	}
    }

    if (*info == 0) {
/* Computing MAX */
	i__1 = 1, i__2 = *n << 1;
	lwkopt = max(i__1,i__2);
	if (nofact) {
	    nb = ilaenv_(&c__1, "ZSYTRF", uplo, n, &c_n1, &c_n1, &c_n1);
/* Computing MAX */
	    i__1 = lwkopt, i__2 = *n * nb;
	    lwkopt = max(i__1,i__2);
	}
	work[1].r = (doublereal) lwkopt, work[1].i = 0.;
    }

    if (*info != 0) {
	i__1 = -(*info);
	xerbla_("ZSYSVX", &i__1);
	return 0;
    } else if (lquery) {
	return 0;
    }

    if (nofact) {

/*        Compute the factorization A = U*D*U' or A = L*D*L'. */

	zlacpy_(uplo, n, n, &a[a_offset], lda, &af[af_offset], ldaf);
	zsytrf_(uplo, n, &af[af_offset], ldaf, &ipiv[1], &work[1], lwork, 
		info);

/*        Return if INFO is non-zero. */

	if (*info > 0) {
	    *rcond = 0.;
	    return 0;
	}
    }

/*     Compute the norm of the matrix A. */

    anorm = zlansy_("I", uplo, n, &a[a_offset], lda, &rwork[1]);

/*     Compute the reciprocal of the condition number of A. */

    zsycon_(uplo, n, &af[af_offset], ldaf, &ipiv[1], &anorm, rcond, &work[1], 
	    info);

/*     Compute the solution vectors X. */

    zlacpy_("Full", n, nrhs, &b[b_offset], ldb, &x[x_offset], ldx);
    zsytrs_(uplo, n, nrhs, &af[af_offset], ldaf, &ipiv[1], &x[x_offset], ldx, 
	    info);

/*     Use iterative refinement to improve the computed solutions and */
/*     compute error bounds and backward error estimates for them. */

    zsyrfs_(uplo, n, nrhs, &a[a_offset], lda, &af[af_offset], ldaf, &ipiv[1], 
	    &b[b_offset], ldb, &x[x_offset], ldx, &ferr[1], &berr[1], &work[1]
, &rwork[1], info);

/*     Set INFO = N+1 if the matrix is singular to working precision. */

    if (*rcond < dlamch_("Epsilon")) {
	*info = *n + 1;
    }

    work[1].r = (doublereal) lwkopt, work[1].i = 0.;

    return 0;

/*     End of ZSYSVX */

} /* zsysvx_ */
Esempio n. 7
0
/* Subroutine */
int zsysvx_(char *fact, char *uplo, integer *n, integer * nrhs, doublecomplex *a, integer *lda, doublecomplex *af, integer * ldaf, integer *ipiv, doublecomplex *b, integer *ldb, doublecomplex *x, integer *ldx, doublereal *rcond, doublereal *ferr, doublereal *berr, doublecomplex *work, integer *lwork, doublereal *rwork, integer *info)
{
    /* System generated locals */
    integer a_dim1, a_offset, af_dim1, af_offset, b_dim1, b_offset, x_dim1, x_offset, i__1, i__2;
    /* Local variables */
    integer nb;
    extern logical lsame_(char *, char *);
    doublereal anorm;
    extern doublereal dlamch_(char *);
    logical nofact;
    extern /* Subroutine */
    int xerbla_(char *, integer *);
    extern integer ilaenv_(integer *, char *, char *, integer *, integer *, integer *, integer *);
    extern /* Subroutine */
    int zlacpy_(char *, integer *, integer *, doublecomplex *, integer *, doublecomplex *, integer *);
    integer lwkopt;
    logical lquery;
    extern doublereal zlansy_(char *, char *, integer *, doublecomplex *, integer *, doublereal *);
    extern /* Subroutine */
    int zsycon_(char *, integer *, doublecomplex *, integer *, integer *, doublereal *, doublereal *, doublecomplex *, integer *), zsyrfs_(char *, integer *, integer *, doublecomplex *, integer *, doublecomplex *, integer *, integer *, doublecomplex *, integer *, doublecomplex *, integer *, doublereal *, doublereal *, doublecomplex *, doublereal *, integer *), zsytrf_(char *, integer *, doublecomplex *, integer *, integer *, doublecomplex *, integer *, integer *), zsytrs_(char *, integer *, integer *, doublecomplex *, integer *, integer *, doublecomplex *, integer *, integer *);
    /* -- LAPACK driver routine (version 3.4.1) -- */
    /* -- LAPACK is a software package provided by Univ. of Tennessee, -- */
    /* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- */
    /* April 2012 */
    /* .. Scalar Arguments .. */
    /* .. */
    /* .. Array Arguments .. */
    /* .. */
    /* ===================================================================== */
    /* .. Parameters .. */
    /* .. */
    /* .. Local Scalars .. */
    /* .. */
    /* .. External Functions .. */
    /* .. */
    /* .. External Subroutines .. */
    /* .. */
    /* .. Intrinsic Functions .. */
    /* .. */
    /* .. Executable Statements .. */
    /* Test the input parameters. */
    /* Parameter adjustments */
    a_dim1 = *lda;
    a_offset = 1 + a_dim1;
    a -= a_offset;
    af_dim1 = *ldaf;
    af_offset = 1 + af_dim1;
    af -= af_offset;
    --ipiv;
    b_dim1 = *ldb;
    b_offset = 1 + b_dim1;
    b -= b_offset;
    x_dim1 = *ldx;
    x_offset = 1 + x_dim1;
    x -= x_offset;
    --ferr;
    --berr;
    --work;
    --rwork;
    /* Function Body */
    *info = 0;
    nofact = lsame_(fact, "N");
    lquery = *lwork == -1;
    if (! nofact && ! lsame_(fact, "F"))
    {
        *info = -1;
    }
    else if (! lsame_(uplo, "U") && ! lsame_(uplo, "L"))
    {
        *info = -2;
    }
    else if (*n < 0)
    {
        *info = -3;
    }
    else if (*nrhs < 0)
    {
        *info = -4;
    }
    else if (*lda < max(1,*n))
    {
        *info = -6;
    }
    else if (*ldaf < max(1,*n))
    {
        *info = -8;
    }
    else if (*ldb < max(1,*n))
    {
        *info = -11;
    }
    else if (*ldx < max(1,*n))
    {
        *info = -13;
    }
    else /* if(complicated condition) */
    {
        /* Computing MAX */
        i__1 = 1;
        i__2 = *n << 1; // , expr subst
        if (*lwork < max(i__1,i__2) && ! lquery)
        {
            *info = -18;
        }
    }
    if (*info == 0)
    {
        /* Computing MAX */
        i__1 = 1;
        i__2 = *n << 1; // , expr subst
        lwkopt = max(i__1,i__2);
        if (nofact)
        {
            nb = ilaenv_(&c__1, "ZSYTRF", uplo, n, &c_n1, &c_n1, &c_n1);
            /* Computing MAX */
            i__1 = lwkopt;
            i__2 = *n * nb; // , expr subst
            lwkopt = max(i__1,i__2);
        }
        work[1].r = (doublereal) lwkopt;
        work[1].i = 0.; // , expr subst
    }
    if (*info != 0)
    {
        i__1 = -(*info);
        xerbla_("ZSYSVX", &i__1);
        return 0;
    }
    else if (lquery)
    {
        return 0;
    }
    if (nofact)
    {
        /* Compute the factorization A = U*D*U**T or A = L*D*L**T. */
        zlacpy_(uplo, n, n, &a[a_offset], lda, &af[af_offset], ldaf);
        zsytrf_(uplo, n, &af[af_offset], ldaf, &ipiv[1], &work[1], lwork, info);
        /* Return if INFO is non-zero. */
        if (*info > 0)
        {
            *rcond = 0.;
            return 0;
        }
    }
    /* Compute the norm of the matrix A. */
    anorm = zlansy_("I", uplo, n, &a[a_offset], lda, &rwork[1]);
    /* Compute the reciprocal of the condition number of A. */
    zsycon_(uplo, n, &af[af_offset], ldaf, &ipiv[1], &anorm, rcond, &work[1], info);
    /* Compute the solution vectors X. */
    zlacpy_("Full", n, nrhs, &b[b_offset], ldb, &x[x_offset], ldx);
    zsytrs_(uplo, n, nrhs, &af[af_offset], ldaf, &ipiv[1], &x[x_offset], ldx, info);
    /* Use iterative refinement to improve the computed solutions and */
    /* compute error bounds and backward error estimates for them. */
    zsyrfs_(uplo, n, nrhs, &a[a_offset], lda, &af[af_offset], ldaf, &ipiv[1], &b[b_offset], ldb, &x[x_offset], ldx, &ferr[1], &berr[1], &work[1] , &rwork[1], info);
    /* Set INFO = N+1 if the matrix is singular to working precision. */
    if (*rcond < dlamch_("Epsilon"))
    {
        *info = *n + 1;
    }
    work[1].r = (doublereal) lwkopt;
    work[1].i = 0.; // , expr subst
    return 0;
    /* End of ZSYSVX */
}
Esempio n. 8
0
/* Subroutine */ int zsycon_(char *uplo, integer *n, doublecomplex *a, 
	integer *lda, integer *ipiv, doublereal *anorm, doublereal *rcond, 
	doublecomplex *work, integer *info)
{
/*  -- LAPACK routine (version 3.0) --   
       Univ. of Tennessee, Univ. of California Berkeley, NAG Ltd.,   
       Courant Institute, Argonne National Lab, and Rice University   
       March 31, 1993   


    Purpose   
    =======   

    ZSYCON estimates the reciprocal of the condition number (in the   
    1-norm) of a complex symmetric matrix A using the factorization   
    A = U*D*U**T or A = L*D*L**T computed by ZSYTRF.   

    An estimate is obtained for norm(inv(A)), and the reciprocal of the   
    condition number is computed as RCOND = 1 / (ANORM * norm(inv(A))).   

    Arguments   
    =========   

    UPLO    (input) CHARACTER*1   
            Specifies whether the details of the factorization are stored   
            as an upper or lower triangular matrix.   
            = 'U':  Upper triangular, form is A = U*D*U**T;   
            = 'L':  Lower triangular, form is A = L*D*L**T.   

    N       (input) INTEGER   
            The order of the matrix A.  N >= 0.   

    A       (input) COMPLEX*16 array, dimension (LDA,N)   
            The block diagonal matrix D and the multipliers used to   
            obtain the factor U or L as computed by ZSYTRF.   

    LDA     (input) INTEGER   
            The leading dimension of the array A.  LDA >= max(1,N).   

    IPIV    (input) INTEGER array, dimension (N)   
            Details of the interchanges and the block structure of D   
            as determined by ZSYTRF.   

    ANORM   (input) DOUBLE PRECISION   
            The 1-norm of the original matrix A.   

    RCOND   (output) DOUBLE PRECISION   
            The reciprocal of the condition number of the matrix A,   
            computed as RCOND = 1/(ANORM * AINVNM), where AINVNM is an   
            estimate of the 1-norm of inv(A) computed in this routine.   

    WORK    (workspace) COMPLEX*16 array, dimension (2*N)   

    INFO    (output) INTEGER   
            = 0:  successful exit   
            < 0:  if INFO = -i, the i-th argument had an illegal value   

    =====================================================================   


       Test the input parameters.   

       Parameter adjustments */
    /* Table of constant values */
    static integer c__1 = 1;
    
    /* System generated locals */
    integer a_dim1, a_offset, i__1, i__2;
    /* Local variables */
    static integer kase, i__;
    extern logical lsame_(char *, char *);
    static logical upper;
    extern /* Subroutine */ int xerbla_(char *, integer *), zlacon_(
	    integer *, doublecomplex *, doublecomplex *, doublereal *, 
	    integer *);
    static doublereal ainvnm;
    extern /* Subroutine */ int zsytrs_(char *, integer *, integer *, 
	    doublecomplex *, integer *, integer *, doublecomplex *, integer *,
	     integer *);
#define a_subscr(a_1,a_2) (a_2)*a_dim1 + a_1
#define a_ref(a_1,a_2) a[a_subscr(a_1,a_2)]


    a_dim1 = *lda;
    a_offset = 1 + a_dim1 * 1;
    a -= a_offset;
    --ipiv;
    --work;

    /* Function Body */
    *info = 0;
    upper = lsame_(uplo, "U");
    if (! upper && ! lsame_(uplo, "L")) {
	*info = -1;
    } else if (*n < 0) {
	*info = -2;
    } else if (*lda < max(1,*n)) {
	*info = -4;
    } else if (*anorm < 0.) {
	*info = -6;
    }
    if (*info != 0) {
	i__1 = -(*info);
	xerbla_("ZSYCON", &i__1);
	return 0;
    }

/*     Quick return if possible */

    *rcond = 0.;
    if (*n == 0) {
	*rcond = 1.;
	return 0;
    } else if (*anorm <= 0.) {
	return 0;
    }

/*     Check that the diagonal matrix D is nonsingular. */

    if (upper) {

/*        Upper triangular storage: examine D from bottom to top */

	for (i__ = *n; i__ >= 1; --i__) {
	    i__1 = a_subscr(i__, i__);
	    if (ipiv[i__] > 0 && (a[i__1].r == 0. && a[i__1].i == 0.)) {
		return 0;
	    }
/* L10: */
	}
    } else {

/*        Lower triangular storage: examine D from top to bottom. */

	i__1 = *n;
	for (i__ = 1; i__ <= i__1; ++i__) {
	    i__2 = a_subscr(i__, i__);
	    if (ipiv[i__] > 0 && (a[i__2].r == 0. && a[i__2].i == 0.)) {
		return 0;
	    }
/* L20: */
	}
    }

/*     Estimate the 1-norm of the inverse. */

    kase = 0;
L30:
    zlacon_(n, &work[*n + 1], &work[1], &ainvnm, &kase);
    if (kase != 0) {

/*        Multiply by inv(L*D*L') or inv(U*D*U'). */

	zsytrs_(uplo, n, &c__1, &a[a_offset], lda, &ipiv[1], &work[1], n, 
		info);
	goto L30;
    }

/*     Compute the estimate of the reciprocal condition number. */

    if (ainvnm != 0.) {
	*rcond = 1. / ainvnm / *anorm;
    }

    return 0;

/*     End of ZSYCON */

} /* zsycon_ */
Esempio n. 9
0
/* Subroutine */
int zsyrfs_(char *uplo, integer *n, integer *nrhs, doublecomplex *a, integer *lda, doublecomplex *af, integer *ldaf, integer *ipiv, doublecomplex *b, integer *ldb, doublecomplex *x, integer *ldx, doublereal *ferr, doublereal *berr, doublecomplex *work, doublereal *rwork, integer *info)
{
    /* System generated locals */
    integer a_dim1, a_offset, af_dim1, af_offset, b_dim1, b_offset, x_dim1, x_offset, i__1, i__2, i__3, i__4, i__5;
    doublereal d__1, d__2, d__3, d__4;
    doublecomplex z__1;
    /* Builtin functions */
    double d_imag(doublecomplex *);
    /* Local variables */
    integer i__, j, k;
    doublereal s, xk;
    integer nz;
    doublereal eps;
    integer kase;
    doublereal safe1, safe2;
    extern logical lsame_(char *, char *);
    integer isave[3], count;
    logical upper;
    extern /* Subroutine */
    int zcopy_(integer *, doublecomplex *, integer *, doublecomplex *, integer *), zaxpy_(integer *, doublecomplex *, doublecomplex *, integer *, doublecomplex *, integer *), zsymv_( char *, integer *, doublecomplex *, doublecomplex *, integer *, doublecomplex *, integer *, doublecomplex *, doublecomplex *, integer *), zlacn2_(integer *, doublecomplex *, doublecomplex *, doublereal *, integer *, integer *);
    extern doublereal dlamch_(char *);
    doublereal safmin;
    extern /* Subroutine */
    int xerbla_(char *, integer *);
    doublereal lstres;
    extern /* Subroutine */
    int zsytrs_(char *, integer *, integer *, doublecomplex *, integer *, integer *, doublecomplex *, integer *, integer *);
    /* -- LAPACK computational routine (version 3.4.0) -- */
    /* -- LAPACK is a software package provided by Univ. of Tennessee, -- */
    /* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- */
    /* November 2011 */
    /* .. Scalar Arguments .. */
    /* .. */
    /* .. Array Arguments .. */
    /* .. */
    /* ===================================================================== */
    /* .. Parameters .. */
    /* .. */
    /* .. Local Scalars .. */
    /* .. */
    /* .. Local Arrays .. */
    /* .. */
    /* .. External Subroutines .. */
    /* .. */
    /* .. Intrinsic Functions .. */
    /* .. */
    /* .. External Functions .. */
    /* .. */
    /* .. Statement Functions .. */
    /* .. */
    /* .. Statement Function definitions .. */
    /* .. */
    /* .. Executable Statements .. */
    /* Test the input parameters. */
    /* Parameter adjustments */
    a_dim1 = *lda;
    a_offset = 1 + a_dim1;
    a -= a_offset;
    af_dim1 = *ldaf;
    af_offset = 1 + af_dim1;
    af -= af_offset;
    --ipiv;
    b_dim1 = *ldb;
    b_offset = 1 + b_dim1;
    b -= b_offset;
    x_dim1 = *ldx;
    x_offset = 1 + x_dim1;
    x -= x_offset;
    --ferr;
    --berr;
    --work;
    --rwork;
    /* Function Body */
    *info = 0;
    upper = lsame_(uplo, "U");
    if (! upper && ! lsame_(uplo, "L"))
    {
        *info = -1;
    }
    else if (*n < 0)
    {
        *info = -2;
    }
    else if (*nrhs < 0)
    {
        *info = -3;
    }
    else if (*lda < max(1,*n))
    {
        *info = -5;
    }
    else if (*ldaf < max(1,*n))
    {
        *info = -7;
    }
    else if (*ldb < max(1,*n))
    {
        *info = -10;
    }
    else if (*ldx < max(1,*n))
    {
        *info = -12;
    }
    if (*info != 0)
    {
        i__1 = -(*info);
        xerbla_("ZSYRFS", &i__1);
        return 0;
    }
    /* Quick return if possible */
    if (*n == 0 || *nrhs == 0)
    {
        i__1 = *nrhs;
        for (j = 1;
                j <= i__1;
                ++j)
        {
            ferr[j] = 0.;
            berr[j] = 0.;
            /* L10: */
        }
        return 0;
    }
    /* NZ = maximum number of nonzero elements in each row of A, plus 1 */
    nz = *n + 1;
    eps = dlamch_("Epsilon");
    safmin = dlamch_("Safe minimum");
    safe1 = nz * safmin;
    safe2 = safe1 / eps;
    /* Do for each right hand side */
    i__1 = *nrhs;
    for (j = 1;
            j <= i__1;
            ++j)
    {
        count = 1;
        lstres = 3.;
L20: /* Loop until stopping criterion is satisfied. */
        /* Compute residual R = B - A * X */
        zcopy_(n, &b[j * b_dim1 + 1], &c__1, &work[1], &c__1);
        z__1.r = -1.;
        z__1.i = -0.; // , expr subst
        zsymv_(uplo, n, &z__1, &a[a_offset], lda, &x[j * x_dim1 + 1], &c__1, & c_b1, &work[1], &c__1);
        /* Compute componentwise relative backward error from formula */
        /* max(i) ( abs(R(i)) / ( abs(A)*abs(X) + abs(B) )(i) ) */
        /* where abs(Z) is the componentwise absolute value of the matrix */
        /* or vector Z. If the i-th component of the denominator is less */
        /* than SAFE2, then SAFE1 is added to the i-th components of the */
        /* numerator and denominator before dividing. */
        i__2 = *n;
        for (i__ = 1;
                i__ <= i__2;
                ++i__)
        {
            i__3 = i__ + j * b_dim1;
            rwork[i__] = (d__1 = b[i__3].r, abs(d__1)) + (d__2 = d_imag(&b[ i__ + j * b_dim1]), abs(d__2));
            /* L30: */
        }
        /* Compute abs(A)*abs(X) + abs(B). */
        if (upper)
        {
            i__2 = *n;
            for (k = 1;
                    k <= i__2;
                    ++k)
            {
                s = 0.;
                i__3 = k + j * x_dim1;
                xk = (d__1 = x[i__3].r, abs(d__1)) + (d__2 = d_imag(&x[k + j * x_dim1]), abs(d__2));
                i__3 = k - 1;
                for (i__ = 1;
                        i__ <= i__3;
                        ++i__)
                {
                    i__4 = i__ + k * a_dim1;
                    rwork[i__] += ((d__1 = a[i__4].r, abs(d__1)) + (d__2 = d_imag(&a[i__ + k * a_dim1]), abs(d__2))) * xk;
                    i__4 = i__ + k * a_dim1;
                    i__5 = i__ + j * x_dim1;
                    s += ((d__1 = a[i__4].r, abs(d__1)) + (d__2 = d_imag(&a[ i__ + k * a_dim1]), abs(d__2))) * ((d__3 = x[i__5] .r, abs(d__3)) + (d__4 = d_imag(&x[i__ + j * x_dim1]), abs(d__4)));
                    /* L40: */
                }
                i__3 = k + k * a_dim1;
                rwork[k] = rwork[k] + ((d__1 = a[i__3].r, abs(d__1)) + (d__2 = d_imag(&a[k + k * a_dim1]), abs(d__2))) * xk + s;
                /* L50: */
            }
        }
        else
        {
            i__2 = *n;
            for (k = 1;
                    k <= i__2;
                    ++k)
            {
                s = 0.;
                i__3 = k + j * x_dim1;
                xk = (d__1 = x[i__3].r, abs(d__1)) + (d__2 = d_imag(&x[k + j * x_dim1]), abs(d__2));
                i__3 = k + k * a_dim1;
                rwork[k] += ((d__1 = a[i__3].r, abs(d__1)) + (d__2 = d_imag(& a[k + k * a_dim1]), abs(d__2))) * xk;
                i__3 = *n;
                for (i__ = k + 1;
                        i__ <= i__3;
                        ++i__)
                {
                    i__4 = i__ + k * a_dim1;
                    rwork[i__] += ((d__1 = a[i__4].r, abs(d__1)) + (d__2 = d_imag(&a[i__ + k * a_dim1]), abs(d__2))) * xk;
                    i__4 = i__ + k * a_dim1;
                    i__5 = i__ + j * x_dim1;
                    s += ((d__1 = a[i__4].r, abs(d__1)) + (d__2 = d_imag(&a[ i__ + k * a_dim1]), abs(d__2))) * ((d__3 = x[i__5] .r, abs(d__3)) + (d__4 = d_imag(&x[i__ + j * x_dim1]), abs(d__4)));
                    /* L60: */
                }
                rwork[k] += s;
                /* L70: */
            }
        }
        s = 0.;
        i__2 = *n;
        for (i__ = 1;
                i__ <= i__2;
                ++i__)
        {
            if (rwork[i__] > safe2)
            {
                /* Computing MAX */
                i__3 = i__;
                d__3 = s;
                d__4 = ((d__1 = work[i__3].r, abs(d__1)) + (d__2 = d_imag(&work[i__]), abs(d__2))) / rwork[i__]; // , expr subst
                s = max(d__3,d__4);
            }
            else
            {
                /* Computing MAX */
                i__3 = i__;
                d__3 = s;
                d__4 = ((d__1 = work[i__3].r, abs(d__1)) + (d__2 = d_imag(&work[i__]), abs(d__2)) + safe1) / (rwork[i__] + safe1); // , expr subst
                s = max(d__3,d__4);
            }
            /* L80: */
        }
        berr[j] = s;
        /* Test stopping criterion. Continue iterating if */
        /* 1) The residual BERR(J) is larger than machine epsilon, and */
        /* 2) BERR(J) decreased by at least a factor of 2 during the */
        /* last iteration, and */
        /* 3) At most ITMAX iterations tried. */
        if (berr[j] > eps && berr[j] * 2. <= lstres && count <= 5)
        {
            /* Update solution and try again. */
            zsytrs_(uplo, n, &c__1, &af[af_offset], ldaf, &ipiv[1], &work[1], n, info);
            zaxpy_(n, &c_b1, &work[1], &c__1, &x[j * x_dim1 + 1], &c__1);
            lstres = berr[j];
            ++count;
            goto L20;
        }
        /* Bound error from formula */
        /* norm(X - XTRUE) / norm(X) .le. FERR = */
        /* norm( abs(inv(A))* */
        /* ( abs(R) + NZ*EPS*( abs(A)*abs(X)+abs(B) ))) / norm(X) */
        /* where */
        /* norm(Z) is the magnitude of the largest component of Z */
        /* inv(A) is the inverse of A */
        /* abs(Z) is the componentwise absolute value of the matrix or */
        /* vector Z */
        /* NZ is the maximum number of nonzeros in any row of A, plus 1 */
        /* EPS is machine epsilon */
        /* The i-th component of abs(R)+NZ*EPS*(abs(A)*abs(X)+abs(B)) */
        /* is incremented by SAFE1 if the i-th component of */
        /* abs(A)*abs(X) + abs(B) is less than SAFE2. */
        /* Use ZLACN2 to estimate the infinity-norm of the matrix */
        /* inv(A) * diag(W), */
        /* where W = abs(R) + NZ*EPS*( abs(A)*abs(X)+abs(B) ))) */
        i__2 = *n;
        for (i__ = 1;
                i__ <= i__2;
                ++i__)
        {
            if (rwork[i__] > safe2)
            {
                i__3 = i__;
                rwork[i__] = (d__1 = work[i__3].r, abs(d__1)) + (d__2 = d_imag(&work[i__]), abs(d__2)) + nz * eps * rwork[i__] ;
            }
            else
            {
                i__3 = i__;
                rwork[i__] = (d__1 = work[i__3].r, abs(d__1)) + (d__2 = d_imag(&work[i__]), abs(d__2)) + nz * eps * rwork[i__] + safe1;
            }
            /* L90: */
        }
        kase = 0;
L100:
        zlacn2_(n, &work[*n + 1], &work[1], &ferr[j], &kase, isave);
        if (kase != 0)
        {
            if (kase == 1)
            {
                /* Multiply by diag(W)*inv(A**T). */
                zsytrs_(uplo, n, &c__1, &af[af_offset], ldaf, &ipiv[1], &work[ 1], n, info);
                i__2 = *n;
                for (i__ = 1;
                        i__ <= i__2;
                        ++i__)
                {
                    i__3 = i__;
                    i__4 = i__;
                    i__5 = i__;
                    z__1.r = rwork[i__4] * work[i__5].r;
                    z__1.i = rwork[i__4] * work[i__5].i; // , expr subst
                    work[i__3].r = z__1.r;
                    work[i__3].i = z__1.i; // , expr subst
                    /* L110: */
                }
            }
            else if (kase == 2)
            {
                /* Multiply by inv(A)*diag(W). */
                i__2 = *n;
                for (i__ = 1;
                        i__ <= i__2;
                        ++i__)
                {
                    i__3 = i__;
                    i__4 = i__;
                    i__5 = i__;
                    z__1.r = rwork[i__4] * work[i__5].r;
                    z__1.i = rwork[i__4] * work[i__5].i; // , expr subst
                    work[i__3].r = z__1.r;
                    work[i__3].i = z__1.i; // , expr subst
                    /* L120: */
                }
                zsytrs_(uplo, n, &c__1, &af[af_offset], ldaf, &ipiv[1], &work[ 1], n, info);
            }
            goto L100;
        }
        /* Normalize error. */
        lstres = 0.;
        i__2 = *n;
        for (i__ = 1;
                i__ <= i__2;
                ++i__)
        {
            /* Computing MAX */
            i__3 = i__ + j * x_dim1;
            d__3 = lstres;
            d__4 = (d__1 = x[i__3].r, abs(d__1)) + (d__2 = d_imag(&x[i__ + j * x_dim1]), abs(d__2)); // , expr subst
            lstres = max(d__3,d__4);
            /* L130: */
        }
        if (lstres != 0.)
        {
            ferr[j] /= lstres;
        }
        /* L140: */
    }
    return 0;
    /* End of ZSYRFS */
}
Esempio n. 10
0
/* Subroutine */
int zsysvxx_(char *fact, char *uplo, integer *n, integer * nrhs, doublecomplex *a, integer *lda, doublecomplex *af, integer * ldaf, integer *ipiv, char *equed, doublereal *s, doublecomplex *b, integer *ldb, doublecomplex *x, integer *ldx, doublereal *rcond, doublereal *rpvgrw, doublereal *berr, integer *n_err_bnds__, doublereal *err_bnds_norm__, doublereal *err_bnds_comp__, integer * nparams, doublereal *params, doublecomplex *work, doublereal *rwork, integer *info)
{
    /* System generated locals */
    integer a_dim1, a_offset, af_dim1, af_offset, b_dim1, b_offset, x_dim1, x_offset, err_bnds_norm_dim1, err_bnds_norm_offset, err_bnds_comp_dim1, err_bnds_comp_offset, i__1;
    doublereal d__1, d__2;
    /* Local variables */
    extern /* Subroutine */
    int zsyrfsx_(char *, char *, integer *, integer *, doublecomplex *, integer *, doublecomplex *, integer *, integer * , doublereal *, doublecomplex *, integer *, doublecomplex *, integer *, doublereal *, doublereal *, integer *, doublereal *, doublereal *, integer *, doublereal *, doublecomplex *, doublereal *, integer *);
    integer j;
    doublereal amax, smin, smax;
    extern logical lsame_(char *, char *);
    doublereal scond;
    extern doublereal zla_syrpvgrw_(char *, integer *, integer *, doublecomplex *, integer *, doublecomplex *, integer *, integer *, doublereal *);
    logical equil, rcequ;
    extern doublereal dlamch_(char *);
    logical nofact;
    extern /* Subroutine */
    int xerbla_(char *, integer *);
    doublereal bignum;
    integer infequ;
    extern /* Subroutine */
    int zlacpy_(char *, integer *, integer *, doublecomplex *, integer *, doublecomplex *, integer *);
    doublereal smlnum;
    extern /* Subroutine */
    int zlaqsy_(char *, integer *, doublecomplex *, integer *, doublereal *, doublereal *, doublereal *, char *), zsytrf_(char *, integer *, doublecomplex *, integer *, integer *, doublecomplex *, integer *, integer *), zlascl2_(integer *, integer *, doublereal *, doublecomplex *, integer *), zsytrs_(char *, integer *, integer *, doublecomplex *, integer *, integer *, doublecomplex *, integer * , integer *), zsyequb_(char *, integer *, doublecomplex *, integer *, doublereal *, doublereal *, doublereal *, doublecomplex *, integer *);
    /* -- LAPACK driver routine (version 3.4.1) -- */
    /* -- LAPACK is a software package provided by Univ. of Tennessee, -- */
    /* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- */
    /* April 2012 */
    /* .. Scalar Arguments .. */
    /* .. */
    /* .. Array Arguments .. */
    /* .. */
    /* ================================================================== */
    /* .. Parameters .. */
    /* .. */
    /* .. Local Scalars .. */
    /* .. */
    /* .. External Functions .. */
    /* .. */
    /* .. External Subroutines .. */
    /* .. */
    /* .. Intrinsic Functions .. */
    /* .. */
    /* .. Executable Statements .. */
    /* Parameter adjustments */
    err_bnds_comp_dim1 = *nrhs;
    err_bnds_comp_offset = 1 + err_bnds_comp_dim1;
    err_bnds_comp__ -= err_bnds_comp_offset;
    err_bnds_norm_dim1 = *nrhs;
    err_bnds_norm_offset = 1 + err_bnds_norm_dim1;
    err_bnds_norm__ -= err_bnds_norm_offset;
    a_dim1 = *lda;
    a_offset = 1 + a_dim1;
    a -= a_offset;
    af_dim1 = *ldaf;
    af_offset = 1 + af_dim1;
    af -= af_offset;
    --ipiv;
    --s;
    b_dim1 = *ldb;
    b_offset = 1 + b_dim1;
    b -= b_offset;
    x_dim1 = *ldx;
    x_offset = 1 + x_dim1;
    x -= x_offset;
    --berr;
    --params;
    --work;
    --rwork;
    /* Function Body */
    *info = 0;
    nofact = lsame_(fact, "N");
    equil = lsame_(fact, "E");
    smlnum = dlamch_("Safe minimum");
    bignum = 1. / smlnum;
    if (nofact || equil)
    {
        *(unsigned char *)equed = 'N';
        rcequ = FALSE_;
    }
    else
    {
        rcequ = lsame_(equed, "Y");
    }
    /* Default is failure. If an input parameter is wrong or */
    /* factorization fails, make everything look horrible. Only the */
    /* pivot growth is set here, the rest is initialized in ZSYRFSX. */
    *rpvgrw = 0.;
    /* Test the input parameters. PARAMS is not tested until ZSYRFSX. */
    if (! nofact && ! equil && ! lsame_(fact, "F"))
    {
        *info = -1;
    }
    else if (! lsame_(uplo, "U") && ! lsame_(uplo, "L"))
    {
        *info = -2;
    }
    else if (*n < 0)
    {
        *info = -3;
    }
    else if (*nrhs < 0)
    {
        *info = -4;
    }
    else if (*lda < max(1,*n))
    {
        *info = -6;
    }
    else if (*ldaf < max(1,*n))
    {
        *info = -8;
    }
    else if (lsame_(fact, "F") && ! (rcequ || lsame_( equed, "N")))
    {
        *info = -9;
    }
    else
    {
        if (rcequ)
        {
            smin = bignum;
            smax = 0.;
            i__1 = *n;
            for (j = 1;
                    j <= i__1;
                    ++j)
            {
                /* Computing MIN */
                d__1 = smin;
                d__2 = s[j]; // , expr subst
                smin = min(d__1,d__2);
                /* Computing MAX */
                d__1 = smax;
                d__2 = s[j]; // , expr subst
                smax = max(d__1,d__2);
                /* L10: */
            }
            if (smin <= 0.)
            {
                *info = -10;
            }
            else if (*n > 0)
            {
                scond = max(smin,smlnum) / min(smax,bignum);
            }
            else
            {
                scond = 1.;
            }
        }
        if (*info == 0)
        {
            if (*ldb < max(1,*n))
            {
                *info = -12;
            }
            else if (*ldx < max(1,*n))
            {
                *info = -14;
            }
        }
    }
    if (*info != 0)
    {
        i__1 = -(*info);
        xerbla_("ZSYSVXX", &i__1);
        return 0;
    }
    if (equil)
    {
        /* Compute row and column scalings to equilibrate the matrix A. */
        zsyequb_(uplo, n, &a[a_offset], lda, &s[1], &scond, &amax, &work[1], & infequ);
        if (infequ == 0)
        {
            /* Equilibrate the matrix. */
            zlaqsy_(uplo, n, &a[a_offset], lda, &s[1], &scond, &amax, equed);
            rcequ = lsame_(equed, "Y");
        }
    }
    /* Scale the right hand-side. */
    if (rcequ)
    {
        zlascl2_(n, nrhs, &s[1], &b[b_offset], ldb);
    }
    if (nofact || equil)
    {
        /* Compute the LDL^T or UDU^T factorization of A. */
        zlacpy_(uplo, n, n, &a[a_offset], lda, &af[af_offset], ldaf);
        i__1 = max(1,*n) * 5;
        zsytrf_(uplo, n, &af[af_offset], ldaf, &ipiv[1], &work[1], &i__1, info);
        /* Return if INFO is non-zero. */
        if (*info > 0)
        {
            /* Pivot in column INFO is exactly 0 */
            /* Compute the reciprocal pivot growth factor of the */
            /* leading rank-deficient INFO columns of A. */
            if (*n > 0)
            {
                *rpvgrw = zla_syrpvgrw_(uplo, n, info, &a[a_offset], lda, & af[af_offset], ldaf, &ipiv[1], &rwork[1]);
            }
            return 0;
        }
    }
    /* Compute the reciprocal pivot growth factor RPVGRW. */
    if (*n > 0)
    {
        *rpvgrw = zla_syrpvgrw_(uplo, n, info, &a[a_offset], lda, &af[ af_offset], ldaf, &ipiv[1], &rwork[1]);
    }
    /* Compute the solution matrix X. */
    zlacpy_("Full", n, nrhs, &b[b_offset], ldb, &x[x_offset], ldx);
    zsytrs_(uplo, n, nrhs, &af[af_offset], ldaf, &ipiv[1], &x[x_offset], ldx, info);
    /* Use iterative refinement to improve the computed solution and */
    /* compute error bounds and backward error estimates for it. */
    zsyrfsx_(uplo, equed, n, nrhs, &a[a_offset], lda, &af[af_offset], ldaf, & ipiv[1], &s[1], &b[b_offset], ldb, &x[x_offset], ldx, rcond, & berr[1], n_err_bnds__, &err_bnds_norm__[err_bnds_norm_offset], & err_bnds_comp__[err_bnds_comp_offset], nparams, &params[1], &work[ 1], &rwork[1], info);
    /* Scale solutions. */
    if (rcequ)
    {
        zlascl2_(n, nrhs, &s[1], &x[x_offset], ldx);
    }
    return 0;
    /* End of ZSYSVXX */
}
Esempio n. 11
0
/* Subroutine */ int zsysvx_(char *fact, char *uplo, integer *n, integer *
	nrhs, doublecomplex *a, integer *lda, doublecomplex *af, integer *
	ldaf, integer *ipiv, doublecomplex *b, integer *ldb, doublecomplex *x,
	 integer *ldx, doublereal *rcond, doublereal *ferr, doublereal *berr, 
	doublecomplex *work, integer *lwork, doublereal *rwork, integer *info)
{
/*  -- LAPACK driver routine (version 2.0) --   
       Univ. of Tennessee, Univ. of California Berkeley, NAG Ltd.,   
       Courant Institute, Argonne National Lab, and Rice University   
       September 30, 1994   


    Purpose   
    =======   

    ZSYSVX uses the diagonal pivoting factorization to compute the   
    solution to a complex system of linear equations A * X = B,   
    where A is an N-by-N symmetric matrix and X and B are N-by-NRHS   
    matrices.   

    Error bounds on the solution and a condition estimate are also   
    provided.   

    Description   
    ===========   

    The following steps are performed:   

    1. If FACT = 'N', the diagonal pivoting method is used to factor A.   
       The form of the factorization is   
          A = U * D * U**T,  if UPLO = 'U', or   
          A = L * D * L**T,  if UPLO = 'L',   
       where U (or L) is a product of permutation and unit upper (lower) 
  
       triangular matrices, and D is symmetric and block diagonal with   
       1-by-1 and 2-by-2 diagonal blocks.   

    2. The factored form of A is used to estimate the condition number   
       of the matrix A.  If the reciprocal of the condition number is   
       less than machine precision, steps 3 and 4 are skipped.   

    3. The system of equations is solved for X using the factored form   
       of A.   

    4. Iterative refinement is applied to improve the computed solution   
       matrix and calculate error bounds and backward error estimates   
       for it.   

    Arguments   
    =========   

    FACT    (input) CHARACTER*1   
            Specifies whether or not the factored form of A has been   
            supplied on entry.   
            = 'F':  On entry, AF and IPIV contain the factored form   
                    of A.  A, AF and IPIV will not be modified.   
            = 'N':  The matrix A will be copied to AF and factored.   

    UPLO    (input) CHARACTER*1   
            = 'U':  Upper triangle of A is stored;   
            = 'L':  Lower triangle of A is stored.   

    N       (input) INTEGER   
            The number of linear equations, i.e., the order of the   
            matrix A.  N >= 0.   

    NRHS    (input) INTEGER   
            The number of right hand sides, i.e., the number of columns   
            of the matrices B and X.  NRHS >= 0.   

    A       (input) COMPLEX*16 array, dimension (LDA,N)   
            The symmetric matrix A.  If UPLO = 'U', the leading N-by-N   
            upper triangular part of A contains the upper triangular part 
  
            of the matrix A, and the strictly lower triangular part of A 
  
            is not referenced.  If UPLO = 'L', the leading N-by-N lower   
            triangular part of A contains the lower triangular part of   
            the matrix A, and the strictly upper triangular part of A is 
  
            not referenced.   

    LDA     (input) INTEGER   
            The leading dimension of the array A.  LDA >= max(1,N).   

    AF      (input or output) COMPLEX*16 array, dimension (LDAF,N)   
            If FACT = 'F', then AF is an input argument and on entry   
            contains the block diagonal matrix D and the multipliers used 
  
            to obtain the factor U or L from the factorization   
            A = U*D*U**T or A = L*D*L**T as computed by ZSYTRF.   

            If FACT = 'N', then AF is an output argument and on exit   
            returns the block diagonal matrix D and the multipliers used 
  
            to obtain the factor U or L from the factorization   
            A = U*D*U**T or A = L*D*L**T.   

    LDAF    (input) INTEGER   
            The leading dimension of the array AF.  LDAF >= max(1,N).   

    IPIV    (input or output) INTEGER array, dimension (N)   
            If FACT = 'F', then IPIV is an input argument and on entry   
            contains details of the interchanges and the block structure 
  
            of D, as determined by ZSYTRF.   
            If IPIV(k) > 0, then rows and columns k and IPIV(k) were   
            interchanged and D(k,k) is a 1-by-1 diagonal block.   
            If UPLO = 'U' and IPIV(k) = IPIV(k-1) < 0, then rows and   
            columns k-1 and -IPIV(k) were interchanged and D(k-1:k,k-1:k) 
  
            is a 2-by-2 diagonal block.  If UPLO = 'L' and IPIV(k) =   
            IPIV(k+1) < 0, then rows and columns k+1 and -IPIV(k) were   
            interchanged and D(k:k+1,k:k+1) is a 2-by-2 diagonal block.   

            If FACT = 'N', then IPIV is an output argument and on exit   
            contains details of the interchanges and the block structure 
  
            of D, as determined by ZSYTRF.   

    B       (input) COMPLEX*16 array, dimension (LDB,NRHS)   
            The N-by-NRHS right hand side matrix B.   

    LDB     (input) INTEGER   
            The leading dimension of the array B.  LDB >= max(1,N).   

    X       (output) COMPLEX*16 array, dimension (LDX,NRHS)   
            If INFO = 0, the N-by-NRHS solution matrix X.   

    LDX     (input) INTEGER   
            The leading dimension of the array X.  LDX >= max(1,N).   

    RCOND   (output) DOUBLE PRECISION   
            The estimate of the reciprocal condition number of the matrix 
  
            A.  If RCOND is less than the machine precision (in   
            particular, if RCOND = 0), the matrix is singular to working 
  
            precision.  This condition is indicated by a return code of   
            INFO > 0, and the solution and error bounds are not computed. 
  

    FERR    (output) DOUBLE PRECISION array, dimension (NRHS)   
            The estimated forward error bound for each solution vector   
            X(j) (the j-th column of the solution matrix X).   
            If XTRUE is the true solution corresponding to X(j), FERR(j) 
  
            is an estimated upper bound for the magnitude of the largest 
  
            element in (X(j) - XTRUE) divided by the magnitude of the   
            largest element in X(j).  The estimate is as reliable as   
            the estimate for RCOND, and is almost always a slight   
            overestimate of the true error.   

    BERR    (output) DOUBLE PRECISION array, dimension (NRHS)   
            The componentwise relative backward error of each solution   
            vector X(j) (i.e., the smallest relative change in   
            any element of A or B that makes X(j) an exact solution).   

    WORK    (workspace/output) COMPLEX*16 array, dimension (LWORK)   
            On exit, if INFO = 0, WORK(1) returns the optimal LWORK.   

    LWORK   (input) INTEGER   
            The length of WORK.  LWORK >= 2*N, and for best performance   
            LWORK >= N*NB, where NB is the optimal blocksize for   
            ZSYTRF.   

    RWORK   (workspace) DOUBLE PRECISION array, dimension (N)   

    INFO    (output) INTEGER   
            = 0: successful exit   
            < 0: if INFO = -i, the i-th argument had an illegal value   
            > 0: if INFO = i, and i is   
                 <= N: D(i,i) is exactly zero.  The factorization   
                       has been completed, but the block diagonal   
                       matrix D is exactly singular, so the solution and 
  
                       error bounds could not be computed.   
                 = N+1: the block diagonal matrix D is nonsingular, but   
                       RCOND is less than machine precision.  The   
                       factorization has been completed, but the matrix   
                       is singular to working precision, so the solution 
  
                       and error bounds have not been computed.   

    ===================================================================== 
  


       Test the input parameters.   

    
   Parameter adjustments   
       Function Body */
    /* System generated locals */
    integer a_dim1, a_offset, af_dim1, af_offset, b_dim1, b_offset, x_dim1, 
	    x_offset, i__1;
    /* Local variables */
    extern logical lsame_(char *, char *);
    static doublereal anorm;
    extern doublereal dlamch_(char *);
    static logical nofact;
    extern /* Subroutine */ int xerbla_(char *, integer *), zlacpy_(
	    char *, integer *, integer *, doublecomplex *, integer *, 
	    doublecomplex *, integer *);
    extern doublereal zlansy_(char *, char *, integer *, doublecomplex *, 
	    integer *, doublereal *);
    extern /* Subroutine */ int zsycon_(char *, integer *, doublecomplex *, 
	    integer *, integer *, doublereal *, doublereal *, doublecomplex *,
	     integer *), zsyrfs_(char *, integer *, integer *, 
	    doublecomplex *, integer *, doublecomplex *, integer *, integer *,
	     doublecomplex *, integer *, doublecomplex *, integer *, 
	    doublereal *, doublereal *, doublecomplex *, doublereal *, 
	    integer *), zsytrf_(char *, integer *, doublecomplex *, 
	    integer *, integer *, doublecomplex *, integer *, integer *), zsytrs_(char *, integer *, integer *, doublecomplex *, 
	    integer *, integer *, doublecomplex *, integer *, integer *);


#define IPIV(I) ipiv[(I)-1]
#define FERR(I) ferr[(I)-1]
#define BERR(I) berr[(I)-1]
#define WORK(I) work[(I)-1]
#define RWORK(I) rwork[(I)-1]

#define A(I,J) a[(I)-1 + ((J)-1)* ( *lda)]
#define AF(I,J) af[(I)-1 + ((J)-1)* ( *ldaf)]
#define B(I,J) b[(I)-1 + ((J)-1)* ( *ldb)]
#define X(I,J) x[(I)-1 + ((J)-1)* ( *ldx)]

    *info = 0;
    nofact = lsame_(fact, "N");
    if (! nofact && ! lsame_(fact, "F")) {
	*info = -1;
    } else if (! lsame_(uplo, "U") && ! lsame_(uplo, "L")) {
	*info = -2;
    } else if (*n < 0) {
	*info = -3;
    } else if (*nrhs < 0) {
	*info = -4;
    } else if (*lda < max(1,*n)) {
	*info = -6;
    } else if (*ldaf < max(1,*n)) {
	*info = -8;
    } else if (*ldb < max(1,*n)) {
	*info = -11;
    } else if (*ldx < max(1,*n)) {
	*info = -13;
    } else if (*lwork < *n << 1) {
	*info = -18;
    }
    if (*info != 0) {
	i__1 = -(*info);
	xerbla_("ZSYSVX", &i__1);
	return 0;
    }

    if (nofact) {

/*        Compute the factorization A = U*D*U' or A = L*D*L'. */

	zlacpy_(uplo, n, n, &A(1,1), lda, &AF(1,1), ldaf);
	zsytrf_(uplo, n, &AF(1,1), ldaf, &IPIV(1), &WORK(1), lwork, 
		info);

/*        Return if INFO is non-zero. */

	if (*info != 0) {
	    if (*info > 0) {
		*rcond = 0.;
	    }
	    return 0;
	}
    }

/*     Compute the norm of the matrix A. */

    anorm = zlansy_("I", uplo, n, &A(1,1), lda, &RWORK(1));

/*     Compute the reciprocal of the condition number of A. */

    zsycon_(uplo, n, &AF(1,1), ldaf, &IPIV(1), &anorm, rcond, &WORK(1), 
	    info);

/*     Return if the matrix is singular to working precision. */

    if (*rcond < dlamch_("Epsilon")) {
	*info = *n + 1;
	return 0;
    }

/*     Compute the solution vectors X. */

    zlacpy_("Full", n, nrhs, &B(1,1), ldb, &X(1,1), ldx);
    zsytrs_(uplo, n, nrhs, &AF(1,1), ldaf, &IPIV(1), &X(1,1), ldx, 
	    info);

/*     Use iterative refinement to improve the computed solutions and   
       compute error bounds and backward error estimates for them. */

    zsyrfs_(uplo, n, nrhs, &A(1,1), lda, &AF(1,1), ldaf, &IPIV(1), 
	    &B(1,1), ldb, &X(1,1), ldx, &FERR(1), &BERR(1), &WORK(1)
	    , &RWORK(1), info);

    return 0;

/*     End of ZSYSVX */

} /* zsysvx_ */
/* Subroutine */ int zla_syrfsx_extended__(integer *prec_type__, char *uplo, 
	integer *n, integer *nrhs, doublecomplex *a, integer *lda, 
	doublecomplex *af, integer *ldaf, integer *ipiv, logical *colequ, 
	doublereal *c__, doublecomplex *b, integer *ldb, doublecomplex *y, 
	integer *ldy, doublereal *berr_out__, integer *n_norms__, doublereal *
	err_bnds_norm__, doublereal *err_bnds_comp__, doublecomplex *res, 
	doublereal *ayb, doublecomplex *dy, doublecomplex *y_tail__, 
	doublereal *rcond, integer *ithresh, doublereal *rthresh, doublereal *
	dz_ub__, logical *ignore_cwise__, integer *info, ftnlen uplo_len)
{
    /* System generated locals */
    integer a_dim1, a_offset, af_dim1, af_offset, b_dim1, b_offset, y_dim1, 
	    y_offset, err_bnds_norm_dim1, err_bnds_norm_offset, 
	    err_bnds_comp_dim1, err_bnds_comp_offset, i__1, i__2, i__3, i__4;
    doublereal d__1, d__2;

    /* Builtin functions */
    double d_imag(doublecomplex *);

    /* Local variables */
    doublereal dxratmax, dzratmax;
    integer i__, j;
    logical incr_prec__;
    doublereal prev_dz_z__;
    extern /* Subroutine */ int zla_syamv__(integer *, integer *, doublereal *
	    , doublecomplex *, integer *, doublecomplex *, integer *, 
	    doublereal *, doublereal *, integer *);
    doublereal yk, final_dx_x__, final_dz_z__;
    extern /* Subroutine */ int zla_wwaddw__(integer *, doublecomplex *, 
	    doublecomplex *, doublecomplex *);
    doublereal prevnormdx;
    integer cnt;
    doublereal dyk, eps, incr_thresh__, dx_x__, dz_z__, ymin;
    extern /* Subroutine */ int zla_lin_berr__(integer *, integer *, integer *
	    , doublecomplex *, doublereal *, doublereal *);
    integer y_prec_state__, uplo2;
    extern /* Subroutine */ int blas_zsymv_x__(integer *, integer *, 
	    doublecomplex *, doublecomplex *, integer *, doublecomplex *, 
	    integer *, doublecomplex *, doublecomplex *, integer *, integer *)
	    ;
    extern logical lsame_(char *, char *);
    doublereal dxrat, dzrat;
    extern /* Subroutine */ int blas_zsymv2_x__(integer *, integer *, 
	    doublecomplex *, doublecomplex *, integer *, doublecomplex *, 
	    doublecomplex *, integer *, doublecomplex *, doublecomplex *, 
	    integer *, integer *);
    doublereal normx, normy;
    extern /* Subroutine */ int zcopy_(integer *, doublecomplex *, integer *, 
	    doublecomplex *, integer *), zaxpy_(integer *, doublecomplex *, 
	    doublecomplex *, integer *, doublecomplex *, integer *), zsymv_(
	    char *, integer *, doublecomplex *, doublecomplex *, integer *, 
	    doublecomplex *, integer *, doublecomplex *, doublecomplex *, 
	    integer *);
    extern doublereal dlamch_(char *);
    doublereal normdx;
    extern /* Subroutine */ int zsytrs_(char *, integer *, integer *, 
	    doublecomplex *, integer *, integer *, doublecomplex *, integer *, 
	     integer *);
    doublereal hugeval;
    extern integer ilauplo_(char *);
    integer x_state__, z_state__;


/*     -- LAPACK routine (version 3.2.1)                                 -- */
/*     -- Contributed by James Demmel, Deaglan Halligan, Yozo Hida and -- */
/*     -- Jason Riedy of Univ. of California Berkeley.                 -- */
/*     -- April 2009                                                   -- */

/*     -- LAPACK is a software package provided by Univ. of Tennessee, -- */
/*     -- Univ. of California Berkeley and NAG Ltd.                    -- */

/*     .. */
/*     .. Scalar Arguments .. */
/*     .. */
/*     .. Array Arguments .. */
/*     .. */

/*  Purpose */
/*  ======= */

/*  ZLA_SYRFSX_EXTENDED improves the computed solution to a system of */
/*  linear equations by performing extra-precise iterative refinement */
/*  and provides error bounds and backward error estimates for the solution. */
/*  This subroutine is called by ZSYRFSX to perform iterative refinement. */
/*  In addition to normwise error bound, the code provides maximum */
/*  componentwise error bound if possible. See comments for ERR_BNDS_NORM */
/*  and ERR_BNDS_COMP for details of the error bounds. Note that this */
/*  subroutine is only resonsible for setting the second fields of */
/*  ERR_BNDS_NORM and ERR_BNDS_COMP. */

/*  Arguments */
/*  ========= */

/*     PREC_TYPE      (input) INTEGER */
/*     Specifies the intermediate precision to be used in refinement. */
/*     The value is defined by ILAPREC(P) where P is a CHARACTER and */
/*     P    = 'S':  Single */
/*          = 'D':  Double */
/*          = 'I':  Indigenous */
/*          = 'X', 'E':  Extra */

/*     UPLO    (input) CHARACTER*1 */
/*       = 'U':  Upper triangle of A is stored; */
/*       = 'L':  Lower triangle of A is stored. */

/*     N              (input) INTEGER */
/*     The number of linear equations, i.e., the order of the */
/*     matrix A.  N >= 0. */

/*     NRHS           (input) INTEGER */
/*     The number of right-hand-sides, i.e., the number of columns of the */
/*     matrix B. */

/*     A              (input) COMPLEX*16 array, dimension (LDA,N) */
/*     On entry, the N-by-N matrix A. */

/*     LDA            (input) INTEGER */
/*     The leading dimension of the array A.  LDA >= max(1,N). */

/*     AF             (input) COMPLEX*16 array, dimension (LDAF,N) */
/*     The block diagonal matrix D and the multipliers used to */
/*     obtain the factor U or L as computed by ZSYTRF. */

/*     LDAF           (input) INTEGER */
/*     The leading dimension of the array AF.  LDAF >= max(1,N). */

/*     IPIV           (input) INTEGER array, dimension (N) */
/*     Details of the interchanges and the block structure of D */
/*     as determined by ZSYTRF. */

/*     COLEQU         (input) LOGICAL */
/*     If .TRUE. then column equilibration was done to A before calling */
/*     this routine. This is needed to compute the solution and error */
/*     bounds correctly. */

/*     C              (input) DOUBLE PRECISION array, dimension (N) */
/*     The column scale factors for A. If COLEQU = .FALSE., C */
/*     is not accessed. If C is input, each element of C should be a power */
/*     of the radix to ensure a reliable solution and error estimates. */
/*     Scaling by powers of the radix does not cause rounding errors unless */
/*     the result underflows or overflows. Rounding errors during scaling */
/*     lead to refining with a matrix that is not equivalent to the */
/*     input matrix, producing error estimates that may not be */
/*     reliable. */

/*     B              (input) COMPLEX*16 array, dimension (LDB,NRHS) */
/*     The right-hand-side matrix B. */

/*     LDB            (input) INTEGER */
/*     The leading dimension of the array B.  LDB >= max(1,N). */

/*     Y              (input/output) COMPLEX*16 array, dimension */
/*                    (LDY,NRHS) */
/*     On entry, the solution matrix X, as computed by ZSYTRS. */
/*     On exit, the improved solution matrix Y. */

/*     LDY            (input) INTEGER */
/*     The leading dimension of the array Y.  LDY >= max(1,N). */

/*     BERR_OUT       (output) DOUBLE PRECISION array, dimension (NRHS) */
/*     On exit, BERR_OUT(j) contains the componentwise relative backward */
/*     error for right-hand-side j from the formula */
/*         max(i) ( abs(RES(i)) / ( abs(op(A_s))*abs(Y) + abs(B_s) )(i) ) */
/*     where abs(Z) is the componentwise absolute value of the matrix */
/*     or vector Z. This is computed by ZLA_LIN_BERR. */

/*     N_NORMS        (input) INTEGER */
/*     Determines which error bounds to return (see ERR_BNDS_NORM */
/*     and ERR_BNDS_COMP). */
/*     If N_NORMS >= 1 return normwise error bounds. */
/*     If N_NORMS >= 2 return componentwise error bounds. */

/*     ERR_BNDS_NORM  (input/output) DOUBLE PRECISION array, dimension */
/*                    (NRHS, N_ERR_BNDS) */
/*     For each right-hand side, this array contains information about */
/*     various error bounds and condition numbers corresponding to the */
/*     normwise relative error, which is defined as follows: */

/*     Normwise relative error in the ith solution vector: */
/*             max_j (abs(XTRUE(j,i) - X(j,i))) */
/*            ------------------------------ */
/*                  max_j abs(X(j,i)) */

/*     The array is indexed by the type of error information as described */
/*     below. There currently are up to three pieces of information */
/*     returned. */

/*     The first index in ERR_BNDS_NORM(i,:) corresponds to the ith */
/*     right-hand side. */

/*     The second index in ERR_BNDS_NORM(:,err) contains the following */
/*     three fields: */
/*     err = 1 "Trust/don't trust" boolean. Trust the answer if the */
/*              reciprocal condition number is less than the threshold */
/*              sqrt(n) * slamch('Epsilon'). */

/*     err = 2 "Guaranteed" error bound: The estimated forward error, */
/*              almost certainly within a factor of 10 of the true error */
/*              so long as the next entry is greater than the threshold */
/*              sqrt(n) * slamch('Epsilon'). This error bound should only */
/*              be trusted if the previous boolean is true. */

/*     err = 3  Reciprocal condition number: Estimated normwise */
/*              reciprocal condition number.  Compared with the threshold */
/*              sqrt(n) * slamch('Epsilon') to determine if the error */
/*              estimate is "guaranteed". These reciprocal condition */
/*              numbers are 1 / (norm(Z^{-1},inf) * norm(Z,inf)) for some */
/*              appropriately scaled matrix Z. */
/*              Let Z = S*A, where S scales each row by a power of the */
/*              radix so all absolute row sums of Z are approximately 1. */

/*     This subroutine is only responsible for setting the second field */
/*     above. */
/*     See Lapack Working Note 165 for further details and extra */
/*     cautions. */

/*     ERR_BNDS_COMP  (input/output) DOUBLE PRECISION array, dimension */
/*                    (NRHS, N_ERR_BNDS) */
/*     For each right-hand side, this array contains information about */
/*     various error bounds and condition numbers corresponding to the */
/*     componentwise relative error, which is defined as follows: */

/*     Componentwise relative error in the ith solution vector: */
/*                    abs(XTRUE(j,i) - X(j,i)) */
/*             max_j ---------------------- */
/*                         abs(X(j,i)) */

/*     The array is indexed by the right-hand side i (on which the */
/*     componentwise relative error depends), and the type of error */
/*     information as described below. There currently are up to three */
/*     pieces of information returned for each right-hand side. If */
/*     componentwise accuracy is not requested (PARAMS(3) = 0.0), then */
/*     ERR_BNDS_COMP is not accessed.  If N_ERR_BNDS .LT. 3, then at most */
/*     the first (:,N_ERR_BNDS) entries are returned. */

/*     The first index in ERR_BNDS_COMP(i,:) corresponds to the ith */
/*     right-hand side. */

/*     The second index in ERR_BNDS_COMP(:,err) contains the following */
/*     three fields: */
/*     err = 1 "Trust/don't trust" boolean. Trust the answer if the */
/*              reciprocal condition number is less than the threshold */
/*              sqrt(n) * slamch('Epsilon'). */

/*     err = 2 "Guaranteed" error bound: The estimated forward error, */
/*              almost certainly within a factor of 10 of the true error */
/*              so long as the next entry is greater than the threshold */
/*              sqrt(n) * slamch('Epsilon'). This error bound should only */
/*              be trusted if the previous boolean is true. */

/*     err = 3  Reciprocal condition number: Estimated componentwise */
/*              reciprocal condition number.  Compared with the threshold */
/*              sqrt(n) * slamch('Epsilon') to determine if the error */
/*              estimate is "guaranteed". These reciprocal condition */
/*              numbers are 1 / (norm(Z^{-1},inf) * norm(Z,inf)) for some */
/*              appropriately scaled matrix Z. */
/*              Let Z = S*(A*diag(x)), where x is the solution for the */
/*              current right-hand side and S scales each row of */
/*              A*diag(x) by a power of the radix so all absolute row */
/*              sums of Z are approximately 1. */

/*     This subroutine is only responsible for setting the second field */
/*     above. */
/*     See Lapack Working Note 165 for further details and extra */
/*     cautions. */

/*     RES            (input) COMPLEX*16 array, dimension (N) */
/*     Workspace to hold the intermediate residual. */

/*     AYB            (input) DOUBLE PRECISION array, dimension (N) */
/*     Workspace. */

/*     DY             (input) COMPLEX*16 array, dimension (N) */
/*     Workspace to hold the intermediate solution. */

/*     Y_TAIL         (input) COMPLEX*16 array, dimension (N) */
/*     Workspace to hold the trailing bits of the intermediate solution. */

/*     RCOND          (input) DOUBLE PRECISION */
/*     Reciprocal scaled condition number.  This is an estimate of the */
/*     reciprocal Skeel condition number of the matrix A after */
/*     equilibration (if done).  If this is less than the machine */
/*     precision (in particular, if it is zero), the matrix is singular */
/*     to working precision.  Note that the error may still be small even */
/*     if this number is very small and the matrix appears ill- */
/*     conditioned. */

/*     ITHRESH        (input) INTEGER */
/*     The maximum number of residual computations allowed for */
/*     refinement. The default is 10. For 'aggressive' set to 100 to */
/*     permit convergence using approximate factorizations or */
/*     factorizations other than LU. If the factorization uses a */
/*     technique other than Gaussian elimination, the guarantees in */
/*     ERR_BNDS_NORM and ERR_BNDS_COMP may no longer be trustworthy. */

/*     RTHRESH        (input) DOUBLE PRECISION */
/*     Determines when to stop refinement if the error estimate stops */
/*     decreasing. Refinement will stop when the next solution no longer */
/*     satisfies norm(dx_{i+1}) < RTHRESH * norm(dx_i) where norm(Z) is */
/*     the infinity norm of Z. RTHRESH satisfies 0 < RTHRESH <= 1. The */
/*     default value is 0.5. For 'aggressive' set to 0.9 to permit */
/*     convergence on extremely ill-conditioned matrices. See LAWN 165 */
/*     for more details. */

/*     DZ_UB          (input) DOUBLE PRECISION */
/*     Determines when to start considering componentwise convergence. */
/*     Componentwise convergence is only considered after each component */
/*     of the solution Y is stable, which we definte as the relative */
/*     change in each component being less than DZ_UB. The default value */
/*     is 0.25, requiring the first bit to be stable. See LAWN 165 for */
/*     more details. */

/*     IGNORE_CWISE   (input) LOGICAL */
/*     If .TRUE. then ignore componentwise convergence. Default value */
/*     is .FALSE.. */

/*     INFO           (output) INTEGER */
/*       = 0:  Successful exit. */
/*       < 0:  if INFO = -i, the ith argument to ZSYTRS had an illegal */
/*             value */

/*  ===================================================================== */

/*     .. Local Scalars .. */
/*     .. */
/*     .. Parameters .. */
/*     .. */
/*     .. External Functions .. */
/*     .. */
/*     .. External Subroutines .. */
/*     .. */
/*     .. Intrinsic Functions .. */
/*     .. */
/*     .. Statement Functions .. */
/*     .. */
/*     .. Statement Function Definitions .. */
/*     .. */
/*     .. Executable Statements .. */

    /* Parameter adjustments */
    err_bnds_comp_dim1 = *nrhs;
    err_bnds_comp_offset = 1 + err_bnds_comp_dim1;
    err_bnds_comp__ -= err_bnds_comp_offset;
    err_bnds_norm_dim1 = *nrhs;
    err_bnds_norm_offset = 1 + err_bnds_norm_dim1;
    err_bnds_norm__ -= err_bnds_norm_offset;
    a_dim1 = *lda;
    a_offset = 1 + a_dim1;
    a -= a_offset;
    af_dim1 = *ldaf;
    af_offset = 1 + af_dim1;
    af -= af_offset;
    --ipiv;
    --c__;
    b_dim1 = *ldb;
    b_offset = 1 + b_dim1;
    b -= b_offset;
    y_dim1 = *ldy;
    y_offset = 1 + y_dim1;
    y -= y_offset;
    --berr_out__;
    --res;
    --ayb;
    --dy;
    --y_tail__;

    /* Function Body */
    if (*info != 0) {
	return 0;
    }
    eps = dlamch_("Epsilon");
    hugeval = dlamch_("Overflow");
/*     Force HUGEVAL to Inf */
    hugeval *= hugeval;
/*     Using HUGEVAL may lead to spurious underflows. */
    incr_thresh__ = (doublereal) (*n) * eps;
    if (lsame_(uplo, "L")) {
	uplo2 = ilauplo_("L");
    } else {
	uplo2 = ilauplo_("U");
    }
    i__1 = *nrhs;
    for (j = 1; j <= i__1; ++j) {
	y_prec_state__ = 1;
	if (y_prec_state__ == 2) {
	    i__2 = *n;
	    for (i__ = 1; i__ <= i__2; ++i__) {
		i__3 = i__;
		y_tail__[i__3].r = 0., y_tail__[i__3].i = 0.;
	    }
	}
	dxrat = 0.;
	dxratmax = 0.;
	dzrat = 0.;
	dzratmax = 0.;
	final_dx_x__ = hugeval;
	final_dz_z__ = hugeval;
	prevnormdx = hugeval;
	prev_dz_z__ = hugeval;
	dz_z__ = hugeval;
	dx_x__ = hugeval;
	x_state__ = 1;
	z_state__ = 0;
	incr_prec__ = FALSE_;
	i__2 = *ithresh;
	for (cnt = 1; cnt <= i__2; ++cnt) {

/*         Compute residual RES = B_s - op(A_s) * Y, */
/*             op(A) = A, A**T, or A**H depending on TRANS (and type). */

	    zcopy_(n, &b[j * b_dim1 + 1], &c__1, &res[1], &c__1);
	    if (y_prec_state__ == 0) {
		zsymv_(uplo, n, &c_b11, &a[a_offset], lda, &y[j * y_dim1 + 1], 
			 &c__1, &c_b12, &res[1], &c__1);
	    } else if (y_prec_state__ == 1) {
		blas_zsymv_x__(&uplo2, n, &c_b11, &a[a_offset], lda, &y[j * 
			y_dim1 + 1], &c__1, &c_b12, &res[1], &c__1, 
			prec_type__);
	    } else {
		blas_zsymv2_x__(&uplo2, n, &c_b11, &a[a_offset], lda, &y[j * 
			y_dim1 + 1], &y_tail__[1], &c__1, &c_b12, &res[1], &
			c__1, prec_type__);
	    }
/*         XXX: RES is no longer needed. */
	    zcopy_(n, &res[1], &c__1, &dy[1], &c__1);
	    zsytrs_(uplo, n, nrhs, &af[af_offset], ldaf, &ipiv[1], &dy[1], n, 
		    info);

/*         Calculate relative changes DX_X, DZ_Z and ratios DXRAT, DZRAT. */

	    normx = 0.;
	    normy = 0.;
	    normdx = 0.;
	    dz_z__ = 0.;
	    ymin = hugeval;
	    i__3 = *n;
	    for (i__ = 1; i__ <= i__3; ++i__) {
		i__4 = i__ + j * y_dim1;
		yk = (d__1 = y[i__4].r, abs(d__1)) + (d__2 = d_imag(&y[i__ + 
			j * y_dim1]), abs(d__2));
		i__4 = i__;
		dyk = (d__1 = dy[i__4].r, abs(d__1)) + (d__2 = d_imag(&dy[i__]
			), abs(d__2));
		if (yk != 0.) {
/* Computing MAX */
		    d__1 = dz_z__, d__2 = dyk / yk;
		    dz_z__ = max(d__1,d__2);
		} else if (dyk != 0.) {
		    dz_z__ = hugeval;
		}
		ymin = min(ymin,yk);
		normy = max(normy,yk);
		if (*colequ) {
/* Computing MAX */
		    d__1 = normx, d__2 = yk * c__[i__];
		    normx = max(d__1,d__2);
/* Computing MAX */
		    d__1 = normdx, d__2 = dyk * c__[i__];
		    normdx = max(d__1,d__2);
		} else {
		    normx = normy;
		    normdx = max(normdx,dyk);
		}
	    }
	    if (normx != 0.) {
		dx_x__ = normdx / normx;
	    } else if (normdx == 0.) {
		dx_x__ = 0.;
	    } else {
		dx_x__ = hugeval;
	    }
	    dxrat = normdx / prevnormdx;
	    dzrat = dz_z__ / prev_dz_z__;

/*         Check termination criteria. */

	    if (ymin * *rcond < incr_thresh__ * normy && y_prec_state__ < 2) {
		incr_prec__ = TRUE_;
	    }
	    if (x_state__ == 3 && dxrat <= *rthresh) {
		x_state__ = 1;
	    }
	    if (x_state__ == 1) {
		if (dx_x__ <= eps) {
		    x_state__ = 2;
		} else if (dxrat > *rthresh) {
		    if (y_prec_state__ != 2) {
			incr_prec__ = TRUE_;
		    } else {
			x_state__ = 3;
		    }
		} else {
		    if (dxrat > dxratmax) {
			dxratmax = dxrat;
		    }
		}
		if (x_state__ > 1) {
		    final_dx_x__ = dx_x__;
		}
	    }
	    if (z_state__ == 0 && dz_z__ <= *dz_ub__) {
		z_state__ = 1;
	    }
	    if (z_state__ == 3 && dzrat <= *rthresh) {
		z_state__ = 1;
	    }
	    if (z_state__ == 1) {
		if (dz_z__ <= eps) {
		    z_state__ = 2;
		} else if (dz_z__ > *dz_ub__) {
		    z_state__ = 0;
		    dzratmax = 0.;
		    final_dz_z__ = hugeval;
		} else if (dzrat > *rthresh) {
		    if (y_prec_state__ != 2) {
			incr_prec__ = TRUE_;
		    } else {
			z_state__ = 3;
		    }
		} else {
		    if (dzrat > dzratmax) {
			dzratmax = dzrat;
		    }
		}
		if (z_state__ > 1) {
		    final_dz_z__ = dz_z__;
		}
	    }
	    if (x_state__ != 1 && (*ignore_cwise__ || z_state__ != 1)) {
		goto L666;
	    }
	    if (incr_prec__) {
		incr_prec__ = FALSE_;
		++y_prec_state__;
		i__3 = *n;
		for (i__ = 1; i__ <= i__3; ++i__) {
		    i__4 = i__;
		    y_tail__[i__4].r = 0., y_tail__[i__4].i = 0.;
		}
	    }
	    prevnormdx = normdx;
	    prev_dz_z__ = dz_z__;

/*           Update soluton. */

	    if (y_prec_state__ < 2) {
		zaxpy_(n, &c_b12, &dy[1], &c__1, &y[j * y_dim1 + 1], &c__1);
	    } else {
		zla_wwaddw__(n, &y[j * y_dim1 + 1], &y_tail__[1], &dy[1]);
	    }
	}
/*        Target of "IF (Z_STOP .AND. X_STOP)".  Sun's f77 won't EXIT. */
L666:

/*     Set final_* when cnt hits ithresh. */

	if (x_state__ == 1) {
	    final_dx_x__ = dx_x__;
	}
	if (z_state__ == 1) {
	    final_dz_z__ = dz_z__;
	}

/*     Compute error bounds. */

	if (*n_norms__ >= 1) {
	    err_bnds_norm__[j + (err_bnds_norm_dim1 << 1)] = final_dx_x__ / (
		    1 - dxratmax);
	}
	if (*n_norms__ >= 2) {
	    err_bnds_comp__[j + (err_bnds_comp_dim1 << 1)] = final_dz_z__ / (
		    1 - dzratmax);
	}

/*     Compute componentwise relative backward error from formula */
/*         max(i) ( abs(R(i)) / ( abs(op(A_s))*abs(Y) + abs(B_s) )(i) ) */
/*     where abs(Z) is the componentwise absolute value of the matrix */
/*     or vector Z. */

/*        Compute residual RES = B_s - op(A_s) * Y, */
/*            op(A) = A, A**T, or A**H depending on TRANS (and type). */

	zcopy_(n, &b[j * b_dim1 + 1], &c__1, &res[1], &c__1);
	zsymv_(uplo, n, &c_b11, &a[a_offset], lda, &y[j * y_dim1 + 1], &c__1, 
		&c_b12, &res[1], &c__1);
	i__2 = *n;
	for (i__ = 1; i__ <= i__2; ++i__) {
	    i__3 = i__ + j * b_dim1;
	    ayb[i__] = (d__1 = b[i__3].r, abs(d__1)) + (d__2 = d_imag(&b[i__ 
		    + j * b_dim1]), abs(d__2));
	}

/*     Compute abs(op(A_s))*abs(Y) + abs(B_s). */

	zla_syamv__(&uplo2, n, &c_b33, &a[a_offset], lda, &y[j * y_dim1 + 1], 
		&c__1, &c_b33, &ayb[1], &c__1);
	zla_lin_berr__(n, n, &c__1, &res[1], &ayb[1], &berr_out__[j]);

/*     End of loop for each RHS. */

    }

    return 0;
} /* zla_syrfsx_extended__ */