Exemple #1
0
/* Subroutine */ int zsprfs_(char *uplo, integer *n, integer *nrhs, 
	doublecomplex *ap, doublecomplex *afp, integer *ipiv, doublecomplex *
	b, integer *ldb, doublecomplex *x, integer *ldx, doublereal *ferr, 
	doublereal *berr, doublecomplex *work, doublereal *rwork, integer *
	info)
{
    /* System generated locals */
    integer 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;
    integer ik, kk;
    doublereal 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 *), zspmv_(
	    char *, integer *, doublecomplex *, doublecomplex *, 
	    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 zsptrs_(char *, integer *, integer *, 
	    doublecomplex *, 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 */
/*  ======= */

/*  ZSPRFS improves the computed solution to a system of linear */
/*  equations when the coefficient matrix is symmetric indefinite */
/*  and packed, 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. */

/*  AP      (input) COMPLEX*16 array, dimension (N*(N+1)/2) */
/*          The upper or lower triangle of the symmetric matrix A, packed */
/*          columnwise in a linear array.  The j-th column of A is stored */
/*          in the array AP as follows: */
/*          if UPLO = 'U', AP(i + (j-1)*j/2) = A(i,j) for 1<=i<=j; */
/*          if UPLO = 'L', AP(i + (j-1)*(2*n-j)/2) = A(i,j) for j<=i<=n. */

/*  AFP     (input) COMPLEX*16 array, dimension (N*(N+1)/2) */
/*          The factored form of the matrix A.  AFP 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 ZSPTRF, stored as a packed */
/*          triangular matrix. */

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

/*  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 ZSPTRS. */
/*          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 */
    --ap;
    --afp;
    --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 (*ldb < max(1,*n)) {
	*info = -8;
    } else if (*ldx < max(1,*n)) {
	*info = -10;
    }
    if (*info != 0) {
	i__1 = -(*info);
	xerbla_("ZSPRFS", &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.;
	zspmv_(uplo, n, &z__1, &ap[1], &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). */

	kk = 1;
	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));
		ik = kk;
		i__3 = k - 1;
		for (i__ = 1; i__ <= i__3; ++i__) {
		    i__4 = ik;
		    rwork[i__] += ((d__1 = ap[i__4].r, abs(d__1)) + (d__2 = 
			    d_imag(&ap[ik]), abs(d__2))) * xk;
		    i__4 = ik;
		    i__5 = i__ + j * x_dim1;
		    s += ((d__1 = ap[i__4].r, abs(d__1)) + (d__2 = d_imag(&ap[
			    ik]), abs(d__2))) * ((d__3 = x[i__5].r, abs(d__3))
			     + (d__4 = d_imag(&x[i__ + j * x_dim1]), abs(d__4)
			    ));
		    ++ik;
/* L40: */
		}
		i__3 = kk + k - 1;
		rwork[k] = rwork[k] + ((d__1 = ap[i__3].r, abs(d__1)) + (d__2 
			= d_imag(&ap[kk + k - 1]), abs(d__2))) * xk + s;
		kk += k;
/* 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 = kk;
		rwork[k] += ((d__1 = ap[i__3].r, abs(d__1)) + (d__2 = d_imag(&
			ap[kk]), abs(d__2))) * xk;
		ik = kk + 1;
		i__3 = *n;
		for (i__ = k + 1; i__ <= i__3; ++i__) {
		    i__4 = ik;
		    rwork[i__] += ((d__1 = ap[i__4].r, abs(d__1)) + (d__2 = 
			    d_imag(&ap[ik]), abs(d__2))) * xk;
		    i__4 = ik;
		    i__5 = i__ + j * x_dim1;
		    s += ((d__1 = ap[i__4].r, abs(d__1)) + (d__2 = d_imag(&ap[
			    ik]), abs(d__2))) * ((d__3 = x[i__5].r, abs(d__3))
			     + (d__4 = d_imag(&x[i__ + j * x_dim1]), abs(d__4)
			    ));
		    ++ik;
/* L60: */
		}
		rwork[k] += s;
		kk += *n - k + 1;
/* 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. */

	    zsptrs_(uplo, n, &c__1, &afp[1], &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'). */

		zsptrs_(uplo, n, &c__1, &afp[1], &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: */
		}
		zsptrs_(uplo, n, &c__1, &afp[1], &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 ZSPRFS */

} /* zsprfs_ */
Exemple #2
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_ */
Exemple #3
0
/* Subroutine */ int zspsvx_(char *fact, char *uplo, integer *n, integer *
                             nrhs, doublecomplex *ap, doublecomplex *afp, integer *ipiv,
                             doublecomplex *b, integer *ldb, doublecomplex *x, integer *ldx,
                             doublereal *rcond, doublereal *ferr, doublereal *berr, doublecomplex *
                             work, doublereal *rwork, integer *info)
{
    /*  -- LAPACK driver routine (version 3.0) --
           Univ. of Tennessee, Univ. of California Berkeley, NAG Ltd.,
           Courant Institute, Argonne National Lab, and Rice University
           June 30, 1999


        Purpose
        =======

        ZSPSVX uses the diagonal pivoting factorization A = U*D*U**T or
        A = L*D*L**T to compute the solution to a complex system of linear
        equations A * X = B, where A is an N-by-N symmetric matrix stored
        in packed format 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 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.

        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, AFP and IPIV contain the factored form
                        of A.  AP, AFP and IPIV will not be modified.
                = 'N':  The matrix A will be copied to AFP 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.

        AP      (input) COMPLEX*16 array, dimension (N*(N+1)/2)
                The upper or lower triangle of the symmetric matrix A, packed
                columnwise in a linear array.  The j-th column of A is stored
                in the array AP as follows:
                if UPLO = 'U', AP(i + (j-1)*j/2) = A(i,j) for 1<=i<=j;
                if UPLO = 'L', AP(i + (j-1)*(2*n-j)/2) = A(i,j) for j<=i<=n.
                See below for further details.

        AFP     (input or output) COMPLEX*16 array, dimension (N*(N+1)/2)
                If FACT = 'F', then AFP 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 ZSPTRF, stored as
                a packed triangular matrix in the same storage format as A.

                If FACT = 'N', then AFP is an output argument and on exit
                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 ZSPTRF, stored as
                a packed triangular matrix in the same storage format as A.

        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 ZSPTRF.
                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 ZSPTRF.

        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) 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
                > 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.

        Further Details
        ===============

        The packed storage scheme is illustrated by the following example
        when N = 4, UPLO = 'U':

        Two-dimensional storage of the symmetric matrix A:

           a11 a12 a13 a14
               a22 a23 a24
                   a33 a34     (aij = aji)
                       a44

        Packed storage of the upper triangle of A:

        AP = [ a11, a12, a22, a13, a23, a33, a14, a24, a34, a44 ]

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


           Test the input parameters.

           Parameter adjustments */
    /* Table of constant values */
    static integer c__1 = 1;

    /* System generated locals */
    integer b_dim1, b_offset, x_dim1, x_offset, i__1;
    /* Local variables */
    extern logical lsame_(char *, char *);
    static doublereal anorm;
    extern /* Subroutine */ int zcopy_(integer *, doublecomplex *, integer *,
                                       doublecomplex *, integer *);
    extern doublereal dlamch_(char *);
    static logical nofact;
    extern /* Subroutine */ int xerbla_(char *, integer *), zlacpy_(
        char *, integer *, integer *, doublecomplex *, integer *,
        doublecomplex *, integer *);
    extern doublereal zlansp_(char *, char *, integer *, doublecomplex *,
                              doublereal *);
    extern /* Subroutine */ int zspcon_(char *, integer *, doublecomplex *,
                                        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 *),
                                                                zsptrs_(char *, integer *, integer *, doublecomplex *, integer *,
                                                                        doublecomplex *, integer *, integer *);


    --ap;
    --afp;
    --ipiv;
    b_dim1 = *ldb;
    b_offset = 1 + b_dim1 * 1;
    b -= b_offset;
    x_dim1 = *ldx;
    x_offset = 1 + x_dim1 * 1;
    x -= x_offset;
    --ferr;
    --berr;
    --work;
    --rwork;

    /* Function Body */
    *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 (*ldb < max(1,*n)) {
        *info = -9;
    } else if (*ldx < max(1,*n)) {
        *info = -11;
    }
    if (*info != 0) {
        i__1 = -(*info);
        xerbla_("ZSPSVX", &i__1);
        return 0;
    }

    if (nofact) {

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

        i__1 = *n * (*n + 1) / 2;
        zcopy_(&i__1, &ap[1], &c__1, &afp[1], &c__1);
        zsptrf_(uplo, n, &afp[1], &ipiv[1], 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 = zlansp_("I", uplo, n, &ap[1], &rwork[1]);

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

    zspcon_(uplo, n, &afp[1], &ipiv[1], &anorm, rcond, &work[1], info);

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

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

    /*     Compute the solution vectors X. */

    zlacpy_("Full", n, nrhs, &b[b_offset], ldb, &x[x_offset], ldx);
    zsptrs_(uplo, n, nrhs, &afp[1], &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. */

    zsprfs_(uplo, n, nrhs, &ap[1], &afp[1], &ipiv[1], &b[b_offset], ldb, &x[
                x_offset], ldx, &ferr[1], &berr[1], &work[1], &rwork[1], info);

    return 0;

    /*     End of ZSPSVX */

} /* zspsvx_ */
/* Subroutine */ int zspsv_(char *uplo, integer *n, integer *nrhs, 
	doublecomplex *ap, integer *ipiv, doublecomplex *b, integer *ldb, 
	integer *info)
{
/*  -- LAPACK driver 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   
    =======   

    ZSPSV computes the solution to a complex system of linear equations   
       A * X = B,   
    where A is an N-by-N symmetric matrix stored in packed format 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, 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.   

    AP      (input/output) COMPLEX*16 array, dimension (N*(N+1)/2)   
            On entry, the upper or lower triangle of the symmetric matrix   
            A, packed columnwise in a linear array.  The j-th column of A   
            is stored in the array AP as follows:   
            if UPLO = 'U', AP(i + (j-1)*j/2) = A(i,j) for 1<=i<=j;   
            if UPLO = 'L', AP(i + (j-1)*(2n-j)/2) = A(i,j) for j<=i<=n.   
            See below for further details.   

            On exit, 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 ZSPTRF, stored as   
            a packed triangular matrix in the same storage format as A.   

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

    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.   

    Further Details   
    ===============   

    The packed storage scheme is illustrated by the following example   
    when N = 4, UPLO = 'U':   

    Two-dimensional storage of the symmetric matrix A:   

       a11 a12 a13 a14   
           a22 a23 a24   
               a33 a34     (aij = aji)   
                   a44   

    Packed storage of the upper triangle of A:   

    AP = [ a11, a12, a22, a13, a23, a33, a14, a24, a34, a44 ]   

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


       Test the input parameters.   

       Parameter adjustments */
    /* System generated locals */
    integer b_dim1, b_offset, i__1;
    /* Local variables */
    extern logical lsame_(char *, char *);
    extern /* Subroutine */ int xerbla_(char *, integer *), zsptrf_(
	    char *, integer *, doublecomplex *, integer *, integer *),
	     zsptrs_(char *, integer *, integer *, doublecomplex *, integer *,
	     doublecomplex *, integer *, integer *);

    --ap;
    --ipiv;
    b_dim1 = *ldb;
    b_offset = 1 + b_dim1 * 1;
    b -= b_offset;

    /* Function Body */
    *info = 0;
    if (! lsame_(uplo, "U") && ! lsame_(uplo, "L")) {
	*info = -1;
    } else if (*n < 0) {
	*info = -2;
    } else if (*nrhs < 0) {
	*info = -3;
    } else if (*ldb < max(1,*n)) {
	*info = -7;
    }
    if (*info != 0) {
	i__1 = -(*info);
	xerbla_("ZSPSV ", &i__1);
	return 0;
    }

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

    zsptrf_(uplo, n, &ap[1], &ipiv[1], info);
    if (*info == 0) {

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

	zsptrs_(uplo, n, nrhs, &ap[1], &ipiv[1], &b[b_offset], ldb, info);

    }
    return 0;

/*     End of ZSPSV */

} /* zspsv_ */