Esempio n. 1
0
 int chgeqz_(char *job, char *compq, char *compz, int *n, 
	int *ilo, int *ihi, complex *h__, int *ldh, complex *t, 
	int *ldt, complex *alpha, complex *beta, complex *q, int *ldq, 
	 complex *z__, int *ldz, complex *work, int *lwork, float *
	rwork, int *info)
{
    /* System generated locals */
    int h_dim1, h_offset, q_dim1, q_offset, t_dim1, t_offset, z_dim1, 
	    z_offset, i__1, i__2, i__3, i__4, i__5, i__6;
    float r__1, r__2, r__3, r__4, r__5, r__6;
    complex q__1, q__2, q__3, q__4, q__5, q__6;

    /* Builtin functions */
    double c_abs(complex *);
    void r_cnjg(complex *, complex *);
    double r_imag(complex *);
    void c_div(complex *, complex *, complex *), pow_ci(complex *, complex *, 
	    int *), c_sqrt(complex *, complex *);

    /* Local variables */
    float c__;
    int j;
    complex s, t1;
    int jc, in;
    complex u12;
    int jr;
    complex ad11, ad12, ad21, ad22;
    int jch;
    int ilq, ilz;
    float ulp;
    complex abi22;
    float absb, atol, btol, temp;
    extern  int crot_(int *, complex *, int *, 
	    complex *, int *, float *, complex *);
    float temp2;
    extern  int cscal_(int *, complex *, complex *, 
	    int *);
    extern int lsame_(char *, char *);
    complex ctemp;
    int iiter, ilast, jiter;
    float anorm, bnorm;
    int maxit;
    complex shift;
    float tempr;
    complex ctemp2, ctemp3;
    int ilazr2;
    float ascale, bscale;
    complex signbc;
    extern double slamch_(char *), clanhs_(char *, int *, 
	    complex *, int *, float *);
    extern  int claset_(char *, int *, int *, complex 
	    *, complex *, complex *, int *), clartg_(complex *, 
	    complex *, float *, complex *, complex *);
    float safmin;
    extern  int xerbla_(char *, int *);
    complex eshift;
    int ilschr;
    int icompq, ilastm;
    complex rtdisc;
    int ischur;
    int ilazro;
    int icompz, ifirst, ifrstm, istart;
    int lquery;


/*  -- LAPACK routine (version 3.2) -- */
/*  -- LAPACK is a software package provided by Univ. of Tennessee,    -- */
/*  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- */
/*     November 2006 */

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

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

/*  CHGEQZ computes the eigenvalues of a complex matrix pair (H,T), */
/*  where H is an upper Hessenberg matrix and T is upper triangular, */
/*  using the single-shift QZ method. */
/*  Matrix pairs of this type are produced by the reduction to */
/*  generalized upper Hessenberg form of a complex matrix pair (A,B): */

/*     A = Q1*H*Z1**H,  B = Q1*T*Z1**H, */

/*  as computed by CGGHRD. */

/*  If JOB='S', then the Hessenberg-triangular pair (H,T) is */
/*  also reduced to generalized Schur form, */

/*     H = Q*S*Z**H,  T = Q*P*Z**H, */

/*  where Q and Z are unitary matrices and S and P are upper triangular. */

/*  Optionally, the unitary matrix Q from the generalized Schur */
/*  factorization may be postmultiplied into an input matrix Q1, and the */
/*  unitary matrix Z may be postmultiplied into an input matrix Z1. */
/*  If Q1 and Z1 are the unitary matrices from CGGHRD that reduced */
/*  the matrix pair (A,B) to generalized Hessenberg form, then the output */
/*  matrices Q1*Q and Z1*Z are the unitary factors from the generalized */
/*  Schur factorization of (A,B): */

/*     A = (Q1*Q)*S*(Z1*Z)**H,  B = (Q1*Q)*P*(Z1*Z)**H. */

/*  To avoid overflow, eigenvalues of the matrix pair (H,T) */
/*  (equivalently, of (A,B)) are computed as a pair of complex values */
/*  (alpha,beta).  If beta is nonzero, lambda = alpha / beta is an */
/*  eigenvalue of the generalized nonsymmetric eigenvalue problem (GNEP) */
/*     A*x = lambda*B*x */
/*  and if alpha is nonzero, mu = beta / alpha is an eigenvalue of the */
/*  alternate form of the GNEP */
/*     mu*A*y = B*y. */
/*  The values of alpha and beta for the i-th eigenvalue can be read */
/*  directly from the generalized Schur form:  alpha = S(i,i), */
/*  beta = P(i,i). */

/*  Ref: C.B. Moler & G.W. Stewart, "An Algorithm for Generalized Matrix */
/*       Eigenvalue Problems", SIAM J. Numer. Anal., 10(1973), */
/*       pp. 241--256. */

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

/*  JOB     (input) CHARACTER*1 */
/*          = 'E': Compute eigenvalues only; */
/*          = 'S': Computer eigenvalues and the Schur form. */

/*  COMPQ   (input) CHARACTER*1 */
/*          = 'N': Left Schur vectors (Q) are not computed; */
/*          = 'I': Q is initialized to the unit matrix and the matrix Q */
/*                 of left Schur vectors of (H,T) is returned; */
/*          = 'V': Q must contain a unitary matrix Q1 on entry and */
/*                 the product Q1*Q is returned. */

/*  COMPZ   (input) CHARACTER*1 */
/*          = 'N': Right Schur vectors (Z) are not computed; */
/*          = 'I': Q is initialized to the unit matrix and the matrix Z */
/*                 of right Schur vectors of (H,T) is returned; */
/*          = 'V': Z must contain a unitary matrix Z1 on entry and */
/*                 the product Z1*Z is returned. */

/*  N       (input) INTEGER */
/*          The order of the matrices H, T, Q, and Z.  N >= 0. */

/*  ILO     (input) INTEGER */
/*  IHI     (input) INTEGER */
/*          ILO and IHI mark the rows and columns of H which are in */
/*          Hessenberg form.  It is assumed that A is already upper */
/*          triangular in rows and columns 1:ILO-1 and IHI+1:N. */
/*          If N > 0, 1 <= ILO <= IHI <= N; if N = 0, ILO=1 and IHI=0. */

/*  H       (input/output) COMPLEX array, dimension (LDH, N) */
/*          On entry, the N-by-N upper Hessenberg matrix H. */
/*          On exit, if JOB = 'S', H contains the upper triangular */
/*          matrix S from the generalized Schur factorization. */
/*          If JOB = 'E', the diagonal of H matches that of S, but */
/*          the rest of H is unspecified. */

/*  LDH     (input) INTEGER */
/*          The leading dimension of the array H.  LDH >= MAX( 1, N ). */

/*  T       (input/output) COMPLEX array, dimension (LDT, N) */
/*          On entry, the N-by-N upper triangular matrix T. */
/*          On exit, if JOB = 'S', T contains the upper triangular */
/*          matrix P from the generalized Schur factorization. */
/*          If JOB = 'E', the diagonal of T matches that of P, but */
/*          the rest of T is unspecified. */

/*  LDT     (input) INTEGER */
/*          The leading dimension of the array T.  LDT >= MAX( 1, N ). */

/*  ALPHA   (output) COMPLEX array, dimension (N) */
/*          The complex scalars alpha that define the eigenvalues of */
/*          GNEP.  ALPHA(i) = S(i,i) in the generalized Schur */
/*          factorization. */

/*  BETA    (output) COMPLEX array, dimension (N) */
/*          The float non-negative scalars beta that define the */
/*          eigenvalues of GNEP.  BETA(i) = P(i,i) in the generalized */
/*          Schur factorization. */

/*          Together, the quantities alpha = ALPHA(j) and beta = BETA(j) */
/*          represent the j-th eigenvalue of the matrix pair (A,B), in */
/*          one of the forms lambda = alpha/beta or mu = beta/alpha. */
/*          Since either lambda or mu may overflow, they should not, */
/*          in general, be computed. */

/*  Q       (input/output) COMPLEX array, dimension (LDQ, N) */
/*          On entry, if COMPZ = 'V', the unitary matrix Q1 used in the */
/*          reduction of (A,B) to generalized Hessenberg form. */
/*          On exit, if COMPZ = 'I', the unitary matrix of left Schur */
/*          vectors of (H,T), and if COMPZ = 'V', the unitary matrix of */
/*          left Schur vectors of (A,B). */
/*          Not referenced if COMPZ = 'N'. */

/*  LDQ     (input) INTEGER */
/*          The leading dimension of the array Q.  LDQ >= 1. */
/*          If COMPQ='V' or 'I', then LDQ >= N. */

/*  Z       (input/output) COMPLEX array, dimension (LDZ, N) */
/*          On entry, if COMPZ = 'V', the unitary matrix Z1 used in the */
/*          reduction of (A,B) to generalized Hessenberg form. */
/*          On exit, if COMPZ = 'I', the unitary matrix of right Schur */
/*          vectors of (H,T), and if COMPZ = 'V', the unitary matrix of */
/*          right Schur vectors of (A,B). */
/*          Not referenced if COMPZ = 'N'. */

/*  LDZ     (input) INTEGER */
/*          The leading dimension of the array Z.  LDZ >= 1. */
/*          If COMPZ='V' or 'I', then LDZ >= N. */

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

/*  LWORK   (input) INTEGER */
/*          The dimension of the array WORK.  LWORK >= MAX(1,N). */

/*          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) REAL array, dimension (N) */

/*  INFO    (output) INTEGER */
/*          = 0: successful exit */
/*          < 0: if INFO = -i, the i-th argument had an illegal value */
/*          = 1,...,N: the QZ iteration did not converge.  (H,T) is not */
/*                     in Schur form, but ALPHA(i) and BETA(i), */
/*                     i=INFO+1,...,N should be correct. */
/*          = N+1,...,2*N: the shift calculation failed.  (H,T) is not */
/*                     in Schur form, but ALPHA(i) and BETA(i), */
/*                     i=INFO-N+1,...,N should be correct. */

/*  Further Details */
/*  =============== */

/*  We assume that complex ABS works as long as its value is less than */
/*  overflow. */

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

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

/*     Decode JOB, COMPQ, COMPZ */

    /* Parameter adjustments */
    h_dim1 = *ldh;
    h_offset = 1 + h_dim1;
    h__ -= h_offset;
    t_dim1 = *ldt;
    t_offset = 1 + t_dim1;
    t -= t_offset;
    --alpha;
    --beta;
    q_dim1 = *ldq;
    q_offset = 1 + q_dim1;
    q -= q_offset;
    z_dim1 = *ldz;
    z_offset = 1 + z_dim1;
    z__ -= z_offset;
    --work;
    --rwork;

    /* Function Body */
    if (lsame_(job, "E")) {
	ilschr = FALSE;
	ischur = 1;
    } else if (lsame_(job, "S")) {
	ilschr = TRUE;
	ischur = 2;
    } else {
	ischur = 0;
    }

    if (lsame_(compq, "N")) {
	ilq = FALSE;
	icompq = 1;
    } else if (lsame_(compq, "V")) {
	ilq = TRUE;
	icompq = 2;
    } else if (lsame_(compq, "I")) {
	ilq = TRUE;
	icompq = 3;
    } else {
	icompq = 0;
    }

    if (lsame_(compz, "N")) {
	ilz = FALSE;
	icompz = 1;
    } else if (lsame_(compz, "V")) {
	ilz = TRUE;
	icompz = 2;
    } else if (lsame_(compz, "I")) {
	ilz = TRUE;
	icompz = 3;
    } else {
	icompz = 0;
    }

/*     Check Argument Values */

    *info = 0;
    i__1 = MAX(1,*n);
    work[1].r = (float) i__1, work[1].i = 0.f;
    lquery = *lwork == -1;
    if (ischur == 0) {
	*info = -1;
    } else if (icompq == 0) {
	*info = -2;
    } else if (icompz == 0) {
	*info = -3;
    } else if (*n < 0) {
	*info = -4;
    } else if (*ilo < 1) {
	*info = -5;
    } else if (*ihi > *n || *ihi < *ilo - 1) {
	*info = -6;
    } else if (*ldh < *n) {
	*info = -8;
    } else if (*ldt < *n) {
	*info = -10;
    } else if (*ldq < 1 || ilq && *ldq < *n) {
	*info = -14;
    } else if (*ldz < 1 || ilz && *ldz < *n) {
	*info = -16;
    } else if (*lwork < MAX(1,*n) && ! lquery) {
	*info = -18;
    }
    if (*info != 0) {
	i__1 = -(*info);
	xerbla_("CHGEQZ", &i__1);
	return 0;
    } else if (lquery) {
	return 0;
    }

/*     Quick return if possible */

/*     WORK( 1 ) = CMPLX( 1 ) */
    if (*n <= 0) {
	work[1].r = 1.f, work[1].i = 0.f;
	return 0;
    }

/*     Initialize Q and Z */

    if (icompq == 3) {
	claset_("Full", n, n, &c_b1, &c_b2, &q[q_offset], ldq);
    }
    if (icompz == 3) {
	claset_("Full", n, n, &c_b1, &c_b2, &z__[z_offset], ldz);
    }

/*     Machine Constants */

    in = *ihi + 1 - *ilo;
    safmin = slamch_("S");
    ulp = slamch_("E") * slamch_("B");
    anorm = clanhs_("F", &in, &h__[*ilo + *ilo * h_dim1], ldh, &rwork[1]);
    bnorm = clanhs_("F", &in, &t[*ilo + *ilo * t_dim1], ldt, &rwork[1]);
/* Computing MAX */
    r__1 = safmin, r__2 = ulp * anorm;
    atol = MAX(r__1,r__2);
/* Computing MAX */
    r__1 = safmin, r__2 = ulp * bnorm;
    btol = MAX(r__1,r__2);
    ascale = 1.f / MAX(safmin,anorm);
    bscale = 1.f / MAX(safmin,bnorm);


/*     Set Eigenvalues IHI+1:N */

    i__1 = *n;
    for (j = *ihi + 1; j <= i__1; ++j) {
	absb = c_abs(&t[j + j * t_dim1]);
	if (absb > safmin) {
	    i__2 = j + j * t_dim1;
	    q__2.r = t[i__2].r / absb, q__2.i = t[i__2].i / absb;
	    r_cnjg(&q__1, &q__2);
	    signbc.r = q__1.r, signbc.i = q__1.i;
	    i__2 = j + j * t_dim1;
	    t[i__2].r = absb, t[i__2].i = 0.f;
	    if (ilschr) {
		i__2 = j - 1;
		cscal_(&i__2, &signbc, &t[j * t_dim1 + 1], &c__1);
		cscal_(&j, &signbc, &h__[j * h_dim1 + 1], &c__1);
	    } else {
		i__2 = j + j * h_dim1;
		i__3 = j + j * h_dim1;
		q__1.r = h__[i__3].r * signbc.r - h__[i__3].i * signbc.i, 
			q__1.i = h__[i__3].r * signbc.i + h__[i__3].i * 
			signbc.r;
		h__[i__2].r = q__1.r, h__[i__2].i = q__1.i;
	    }
	    if (ilz) {
		cscal_(n, &signbc, &z__[j * z_dim1 + 1], &c__1);
	    }
	} else {
	    i__2 = j + j * t_dim1;
	    t[i__2].r = 0.f, t[i__2].i = 0.f;
	}
	i__2 = j;
	i__3 = j + j * h_dim1;
	alpha[i__2].r = h__[i__3].r, alpha[i__2].i = h__[i__3].i;
	i__2 = j;
	i__3 = j + j * t_dim1;
	beta[i__2].r = t[i__3].r, beta[i__2].i = t[i__3].i;
/* L10: */
    }

/*     If IHI < ILO, skip QZ steps */

    if (*ihi < *ilo) {
	goto L190;
    }

/*     MAIN QZ ITERATION LOOP */

/*     Initialize dynamic indices */

/*     Eigenvalues ILAST+1:N have been found. */
/*        Column operations modify rows IFRSTM:whatever */
/*        Row operations modify columns whatever:ILASTM */

/*     If only eigenvalues are being computed, then */
/*        IFRSTM is the row of the last splitting row above row ILAST; */
/*        this is always at least ILO. */
/*     IITER counts iterations since the last eigenvalue was found, */
/*        to tell when to use an extraordinary shift. */
/*     MAXIT is the maximum number of QZ sweeps allowed. */

    ilast = *ihi;
    if (ilschr) {
	ifrstm = 1;
	ilastm = *n;
    } else {
	ifrstm = *ilo;
	ilastm = *ihi;
    }
    iiter = 0;
    eshift.r = 0.f, eshift.i = 0.f;
    maxit = (*ihi - *ilo + 1) * 30;

    i__1 = maxit;
    for (jiter = 1; jiter <= i__1; ++jiter) {

/*        Check for too many iterations. */

	if (jiter > maxit) {
	    goto L180;
	}

/*        Split the matrix if possible. */

/*        Two tests: */
/*           1: H(j,j-1)=0  or  j=ILO */
/*           2: T(j,j)=0 */

/*        Special case: j=ILAST */

	if (ilast == *ilo) {
	    goto L60;
	} else {
	    i__2 = ilast + (ilast - 1) * h_dim1;
	    if ((r__1 = h__[i__2].r, ABS(r__1)) + (r__2 = r_imag(&h__[ilast 
		    + (ilast - 1) * h_dim1]), ABS(r__2)) <= atol) {
		i__2 = ilast + (ilast - 1) * h_dim1;
		h__[i__2].r = 0.f, h__[i__2].i = 0.f;
		goto L60;
	    }
	}

	if (c_abs(&t[ilast + ilast * t_dim1]) <= btol) {
	    i__2 = ilast + ilast * t_dim1;
	    t[i__2].r = 0.f, t[i__2].i = 0.f;
	    goto L50;
	}

/*        General case: j<ILAST */

	i__2 = *ilo;
	for (j = ilast - 1; j >= i__2; --j) {

/*           Test 1: for H(j,j-1)=0 or j=ILO */

	    if (j == *ilo) {
		ilazro = TRUE;
	    } else {
		i__3 = j + (j - 1) * h_dim1;
		if ((r__1 = h__[i__3].r, ABS(r__1)) + (r__2 = r_imag(&h__[j 
			+ (j - 1) * h_dim1]), ABS(r__2)) <= atol) {
		    i__3 = j + (j - 1) * h_dim1;
		    h__[i__3].r = 0.f, h__[i__3].i = 0.f;
		    ilazro = TRUE;
		} else {
		    ilazro = FALSE;
		}
	    }

/*           Test 2: for T(j,j)=0 */

	    if (c_abs(&t[j + j * t_dim1]) < btol) {
		i__3 = j + j * t_dim1;
		t[i__3].r = 0.f, t[i__3].i = 0.f;

/*              Test 1a: Check for 2 consecutive small subdiagonals in A */

		ilazr2 = FALSE;
		if (! ilazro) {
		    i__3 = j + (j - 1) * h_dim1;
		    i__4 = j + 1 + j * h_dim1;
		    i__5 = j + j * h_dim1;
		    if (((r__1 = h__[i__3].r, ABS(r__1)) + (r__2 = r_imag(&
			    h__[j + (j - 1) * h_dim1]), ABS(r__2))) * (
			    ascale * ((r__3 = h__[i__4].r, ABS(r__3)) + (
			    r__4 = r_imag(&h__[j + 1 + j * h_dim1]), ABS(
			    r__4)))) <= ((r__5 = h__[i__5].r, ABS(r__5)) + (
			    r__6 = r_imag(&h__[j + j * h_dim1]), ABS(r__6))) 
			    * (ascale * atol)) {
			ilazr2 = TRUE;
		    }
		}

/*              If both tests pass (1 & 2), i.e., the leading diagonal */
/*              element of B in the block is zero, split a 1x1 block off */
/*              at the top. (I.e., at the J-th row/column) The leading */
/*              diagonal element of the remainder can also be zero, so */
/*              this may have to be done repeatedly. */

		if (ilazro || ilazr2) {
		    i__3 = ilast - 1;
		    for (jch = j; jch <= i__3; ++jch) {
			i__4 = jch + jch * h_dim1;
			ctemp.r = h__[i__4].r, ctemp.i = h__[i__4].i;
			clartg_(&ctemp, &h__[jch + 1 + jch * h_dim1], &c__, &
				s, &h__[jch + jch * h_dim1]);
			i__4 = jch + 1 + jch * h_dim1;
			h__[i__4].r = 0.f, h__[i__4].i = 0.f;
			i__4 = ilastm - jch;
			crot_(&i__4, &h__[jch + (jch + 1) * h_dim1], ldh, &
				h__[jch + 1 + (jch + 1) * h_dim1], ldh, &c__, 
				&s);
			i__4 = ilastm - jch;
			crot_(&i__4, &t[jch + (jch + 1) * t_dim1], ldt, &t[
				jch + 1 + (jch + 1) * t_dim1], ldt, &c__, &s);
			if (ilq) {
			    r_cnjg(&q__1, &s);
			    crot_(n, &q[jch * q_dim1 + 1], &c__1, &q[(jch + 1)
				     * q_dim1 + 1], &c__1, &c__, &q__1);
			}
			if (ilazr2) {
			    i__4 = jch + (jch - 1) * h_dim1;
			    i__5 = jch + (jch - 1) * h_dim1;
			    q__1.r = c__ * h__[i__5].r, q__1.i = c__ * h__[
				    i__5].i;
			    h__[i__4].r = q__1.r, h__[i__4].i = q__1.i;
			}
			ilazr2 = FALSE;
			i__4 = jch + 1 + (jch + 1) * t_dim1;
			if ((r__1 = t[i__4].r, ABS(r__1)) + (r__2 = r_imag(&
				t[jch + 1 + (jch + 1) * t_dim1]), ABS(r__2)) 
				>= btol) {
			    if (jch + 1 >= ilast) {
				goto L60;
			    } else {
				ifirst = jch + 1;
				goto L70;
			    }
			}
			i__4 = jch + 1 + (jch + 1) * t_dim1;
			t[i__4].r = 0.f, t[i__4].i = 0.f;
/* L20: */
		    }
		    goto L50;
		} else {

/*                 Only test 2 passed -- chase the zero to T(ILAST,ILAST) */
/*                 Then process as in the case T(ILAST,ILAST)=0 */

		    i__3 = ilast - 1;
		    for (jch = j; jch <= i__3; ++jch) {
			i__4 = jch + (jch + 1) * t_dim1;
			ctemp.r = t[i__4].r, ctemp.i = t[i__4].i;
			clartg_(&ctemp, &t[jch + 1 + (jch + 1) * t_dim1], &
				c__, &s, &t[jch + (jch + 1) * t_dim1]);
			i__4 = jch + 1 + (jch + 1) * t_dim1;
			t[i__4].r = 0.f, t[i__4].i = 0.f;
			if (jch < ilastm - 1) {
			    i__4 = ilastm - jch - 1;
			    crot_(&i__4, &t[jch + (jch + 2) * t_dim1], ldt, &
				    t[jch + 1 + (jch + 2) * t_dim1], ldt, &
				    c__, &s);
			}
			i__4 = ilastm - jch + 2;
			crot_(&i__4, &h__[jch + (jch - 1) * h_dim1], ldh, &
				h__[jch + 1 + (jch - 1) * h_dim1], ldh, &c__, 
				&s);
			if (ilq) {
			    r_cnjg(&q__1, &s);
			    crot_(n, &q[jch * q_dim1 + 1], &c__1, &q[(jch + 1)
				     * q_dim1 + 1], &c__1, &c__, &q__1);
			}
			i__4 = jch + 1 + jch * h_dim1;
			ctemp.r = h__[i__4].r, ctemp.i = h__[i__4].i;
			clartg_(&ctemp, &h__[jch + 1 + (jch - 1) * h_dim1], &
				c__, &s, &h__[jch + 1 + jch * h_dim1]);
			i__4 = jch + 1 + (jch - 1) * h_dim1;
			h__[i__4].r = 0.f, h__[i__4].i = 0.f;
			i__4 = jch + 1 - ifrstm;
			crot_(&i__4, &h__[ifrstm + jch * h_dim1], &c__1, &h__[
				ifrstm + (jch - 1) * h_dim1], &c__1, &c__, &s)
				;
			i__4 = jch - ifrstm;
			crot_(&i__4, &t[ifrstm + jch * t_dim1], &c__1, &t[
				ifrstm + (jch - 1) * t_dim1], &c__1, &c__, &s)
				;
			if (ilz) {
			    crot_(n, &z__[jch * z_dim1 + 1], &c__1, &z__[(jch 
				    - 1) * z_dim1 + 1], &c__1, &c__, &s);
			}
/* L30: */
		    }
		    goto L50;
		}
	    } else if (ilazro) {

/*              Only test 1 passed -- work on J:ILAST */

		ifirst = j;
		goto L70;
	    }

/*           Neither test passed -- try next J */

/* L40: */
	}

/*        (Drop-through is "impossible") */

	*info = (*n << 1) + 1;
	goto L210;

/*        T(ILAST,ILAST)=0 -- clear H(ILAST,ILAST-1) to split off a */
/*        1x1 block. */

L50:
	i__2 = ilast + ilast * h_dim1;
	ctemp.r = h__[i__2].r, ctemp.i = h__[i__2].i;
	clartg_(&ctemp, &h__[ilast + (ilast - 1) * h_dim1], &c__, &s, &h__[
		ilast + ilast * h_dim1]);
	i__2 = ilast + (ilast - 1) * h_dim1;
	h__[i__2].r = 0.f, h__[i__2].i = 0.f;
	i__2 = ilast - ifrstm;
	crot_(&i__2, &h__[ifrstm + ilast * h_dim1], &c__1, &h__[ifrstm + (
		ilast - 1) * h_dim1], &c__1, &c__, &s);
	i__2 = ilast - ifrstm;
	crot_(&i__2, &t[ifrstm + ilast * t_dim1], &c__1, &t[ifrstm + (ilast - 
		1) * t_dim1], &c__1, &c__, &s);
	if (ilz) {
	    crot_(n, &z__[ilast * z_dim1 + 1], &c__1, &z__[(ilast - 1) * 
		    z_dim1 + 1], &c__1, &c__, &s);
	}

/*        H(ILAST,ILAST-1)=0 -- Standardize B, set ALPHA and BETA */

L60:
	absb = c_abs(&t[ilast + ilast * t_dim1]);
	if (absb > safmin) {
	    i__2 = ilast + ilast * t_dim1;
	    q__2.r = t[i__2].r / absb, q__2.i = t[i__2].i / absb;
	    r_cnjg(&q__1, &q__2);
	    signbc.r = q__1.r, signbc.i = q__1.i;
	    i__2 = ilast + ilast * t_dim1;
	    t[i__2].r = absb, t[i__2].i = 0.f;
	    if (ilschr) {
		i__2 = ilast - ifrstm;
		cscal_(&i__2, &signbc, &t[ifrstm + ilast * t_dim1], &c__1);
		i__2 = ilast + 1 - ifrstm;
		cscal_(&i__2, &signbc, &h__[ifrstm + ilast * h_dim1], &c__1);
	    } else {
		i__2 = ilast + ilast * h_dim1;
		i__3 = ilast + ilast * h_dim1;
		q__1.r = h__[i__3].r * signbc.r - h__[i__3].i * signbc.i, 
			q__1.i = h__[i__3].r * signbc.i + h__[i__3].i * 
			signbc.r;
		h__[i__2].r = q__1.r, h__[i__2].i = q__1.i;
	    }
	    if (ilz) {
		cscal_(n, &signbc, &z__[ilast * z_dim1 + 1], &c__1);
	    }
	} else {
	    i__2 = ilast + ilast * t_dim1;
	    t[i__2].r = 0.f, t[i__2].i = 0.f;
	}
	i__2 = ilast;
	i__3 = ilast + ilast * h_dim1;
	alpha[i__2].r = h__[i__3].r, alpha[i__2].i = h__[i__3].i;
	i__2 = ilast;
	i__3 = ilast + ilast * t_dim1;
	beta[i__2].r = t[i__3].r, beta[i__2].i = t[i__3].i;

/*        Go to next block -- exit if finished. */

	--ilast;
	if (ilast < *ilo) {
	    goto L190;
	}

/*        Reset counters */

	iiter = 0;
	eshift.r = 0.f, eshift.i = 0.f;
	if (! ilschr) {
	    ilastm = ilast;
	    if (ifrstm > ilast) {
		ifrstm = *ilo;
	    }
	}
	goto L160;

/*        QZ step */

/*        This iteration only involves rows/columns IFIRST:ILAST.  We */
/*        assume IFIRST < ILAST, and that the diagonal of B is non-zero. */

L70:
	++iiter;
	if (! ilschr) {
	    ifrstm = ifirst;
	}

/*        Compute the Shift. */

/*        At this point, IFIRST < ILAST, and the diagonal elements of */
/*        T(IFIRST:ILAST,IFIRST,ILAST) are larger than BTOL (in */
/*        magnitude) */

	if (iiter / 10 * 10 != iiter) {

/*           The Wilkinson shift (AEP p.512), i.e., the eigenvalue of */
/*           the bottom-right 2x2 block of A inv(B) which is nearest to */
/*           the bottom-right element. */

/*           We factor B as U*D, where U has unit diagonals, and */
/*           compute (A*inv(D))*inv(U). */

	    i__2 = ilast - 1 + ilast * t_dim1;
	    q__2.r = bscale * t[i__2].r, q__2.i = bscale * t[i__2].i;
	    i__3 = ilast + ilast * t_dim1;
	    q__3.r = bscale * t[i__3].r, q__3.i = bscale * t[i__3].i;
	    c_div(&q__1, &q__2, &q__3);
	    u12.r = q__1.r, u12.i = q__1.i;
	    i__2 = ilast - 1 + (ilast - 1) * h_dim1;
	    q__2.r = ascale * h__[i__2].r, q__2.i = ascale * h__[i__2].i;
	    i__3 = ilast - 1 + (ilast - 1) * t_dim1;
	    q__3.r = bscale * t[i__3].r, q__3.i = bscale * t[i__3].i;
	    c_div(&q__1, &q__2, &q__3);
	    ad11.r = q__1.r, ad11.i = q__1.i;
	    i__2 = ilast + (ilast - 1) * h_dim1;
	    q__2.r = ascale * h__[i__2].r, q__2.i = ascale * h__[i__2].i;
	    i__3 = ilast - 1 + (ilast - 1) * t_dim1;
	    q__3.r = bscale * t[i__3].r, q__3.i = bscale * t[i__3].i;
	    c_div(&q__1, &q__2, &q__3);
	    ad21.r = q__1.r, ad21.i = q__1.i;
	    i__2 = ilast - 1 + ilast * h_dim1;
	    q__2.r = ascale * h__[i__2].r, q__2.i = ascale * h__[i__2].i;
	    i__3 = ilast + ilast * t_dim1;
	    q__3.r = bscale * t[i__3].r, q__3.i = bscale * t[i__3].i;
	    c_div(&q__1, &q__2, &q__3);
	    ad12.r = q__1.r, ad12.i = q__1.i;
	    i__2 = ilast + ilast * h_dim1;
	    q__2.r = ascale * h__[i__2].r, q__2.i = ascale * h__[i__2].i;
	    i__3 = ilast + ilast * t_dim1;
	    q__3.r = bscale * t[i__3].r, q__3.i = bscale * t[i__3].i;
	    c_div(&q__1, &q__2, &q__3);
	    ad22.r = q__1.r, ad22.i = q__1.i;
	    q__2.r = u12.r * ad21.r - u12.i * ad21.i, q__2.i = u12.r * ad21.i 
		    + u12.i * ad21.r;
	    q__1.r = ad22.r - q__2.r, q__1.i = ad22.i - q__2.i;
	    abi22.r = q__1.r, abi22.i = q__1.i;

	    q__2.r = ad11.r + abi22.r, q__2.i = ad11.i + abi22.i;
	    q__1.r = q__2.r * .5f, q__1.i = q__2.i * .5f;
	    t1.r = q__1.r, t1.i = q__1.i;
	    pow_ci(&q__4, &t1, &c__2);
	    q__5.r = ad12.r * ad21.r - ad12.i * ad21.i, q__5.i = ad12.r * 
		    ad21.i + ad12.i * ad21.r;
	    q__3.r = q__4.r + q__5.r, q__3.i = q__4.i + q__5.i;
	    q__6.r = ad11.r * ad22.r - ad11.i * ad22.i, q__6.i = ad11.r * 
		    ad22.i + ad11.i * ad22.r;
	    q__2.r = q__3.r - q__6.r, q__2.i = q__3.i - q__6.i;
	    c_sqrt(&q__1, &q__2);
	    rtdisc.r = q__1.r, rtdisc.i = q__1.i;
	    q__1.r = t1.r - abi22.r, q__1.i = t1.i - abi22.i;
	    q__2.r = t1.r - abi22.r, q__2.i = t1.i - abi22.i;
	    temp = q__1.r * rtdisc.r + r_imag(&q__2) * r_imag(&rtdisc);
	    if (temp <= 0.f) {
		q__1.r = t1.r + rtdisc.r, q__1.i = t1.i + rtdisc.i;
		shift.r = q__1.r, shift.i = q__1.i;
	    } else {
		q__1.r = t1.r - rtdisc.r, q__1.i = t1.i - rtdisc.i;
		shift.r = q__1.r, shift.i = q__1.i;
	    }
	} else {

/*           Exceptional shift.  Chosen for no particularly good reason. */

	    i__2 = ilast - 1 + ilast * h_dim1;
	    q__4.r = ascale * h__[i__2].r, q__4.i = ascale * h__[i__2].i;
	    i__3 = ilast - 1 + (ilast - 1) * t_dim1;
	    q__5.r = bscale * t[i__3].r, q__5.i = bscale * t[i__3].i;
	    c_div(&q__3, &q__4, &q__5);
	    r_cnjg(&q__2, &q__3);
	    q__1.r = eshift.r + q__2.r, q__1.i = eshift.i + q__2.i;
	    eshift.r = q__1.r, eshift.i = q__1.i;
	    shift.r = eshift.r, shift.i = eshift.i;
	}

/*        Now check for two consecutive small subdiagonals. */

	i__2 = ifirst + 1;
	for (j = ilast - 1; j >= i__2; --j) {
	    istart = j;
	    i__3 = j + j * h_dim1;
	    q__2.r = ascale * h__[i__3].r, q__2.i = ascale * h__[i__3].i;
	    i__4 = j + j * t_dim1;
	    q__4.r = bscale * t[i__4].r, q__4.i = bscale * t[i__4].i;
	    q__3.r = shift.r * q__4.r - shift.i * q__4.i, q__3.i = shift.r * 
		    q__4.i + shift.i * q__4.r;
	    q__1.r = q__2.r - q__3.r, q__1.i = q__2.i - q__3.i;
	    ctemp.r = q__1.r, ctemp.i = q__1.i;
	    temp = (r__1 = ctemp.r, ABS(r__1)) + (r__2 = r_imag(&ctemp), 
		    ABS(r__2));
	    i__3 = j + 1 + j * h_dim1;
	    temp2 = ascale * ((r__1 = h__[i__3].r, ABS(r__1)) + (r__2 = 
		    r_imag(&h__[j + 1 + j * h_dim1]), ABS(r__2)));
	    tempr = MAX(temp,temp2);
	    if (tempr < 1.f && tempr != 0.f) {
		temp /= tempr;
		temp2 /= tempr;
	    }
	    i__3 = j + (j - 1) * h_dim1;
	    if (((r__1 = h__[i__3].r, ABS(r__1)) + (r__2 = r_imag(&h__[j + (
		    j - 1) * h_dim1]), ABS(r__2))) * temp2 <= temp * atol) {
		goto L90;
	    }
/* L80: */
	}

	istart = ifirst;
	i__2 = ifirst + ifirst * h_dim1;
	q__2.r = ascale * h__[i__2].r, q__2.i = ascale * h__[i__2].i;
	i__3 = ifirst + ifirst * t_dim1;
	q__4.r = bscale * t[i__3].r, q__4.i = bscale * t[i__3].i;
	q__3.r = shift.r * q__4.r - shift.i * q__4.i, q__3.i = shift.r * 
		q__4.i + shift.i * q__4.r;
	q__1.r = q__2.r - q__3.r, q__1.i = q__2.i - q__3.i;
	ctemp.r = q__1.r, ctemp.i = q__1.i;
L90:

/*        Do an implicit-shift QZ sweep. */

/*        Initial Q */

	i__2 = istart + 1 + istart * h_dim1;
	q__1.r = ascale * h__[i__2].r, q__1.i = ascale * h__[i__2].i;
	ctemp2.r = q__1.r, ctemp2.i = q__1.i;
	clartg_(&ctemp, &ctemp2, &c__, &s, &ctemp3);

/*        Sweep */

	i__2 = ilast - 1;
	for (j = istart; j <= i__2; ++j) {
	    if (j > istart) {
		i__3 = j + (j - 1) * h_dim1;
		ctemp.r = h__[i__3].r, ctemp.i = h__[i__3].i;
		clartg_(&ctemp, &h__[j + 1 + (j - 1) * h_dim1], &c__, &s, &
			h__[j + (j - 1) * h_dim1]);
		i__3 = j + 1 + (j - 1) * h_dim1;
		h__[i__3].r = 0.f, h__[i__3].i = 0.f;
	    }

	    i__3 = ilastm;
	    for (jc = j; jc <= i__3; ++jc) {
		i__4 = j + jc * h_dim1;
		q__2.r = c__ * h__[i__4].r, q__2.i = c__ * h__[i__4].i;
		i__5 = j + 1 + jc * h_dim1;
		q__3.r = s.r * h__[i__5].r - s.i * h__[i__5].i, q__3.i = s.r *
			 h__[i__5].i + s.i * h__[i__5].r;
		q__1.r = q__2.r + q__3.r, q__1.i = q__2.i + q__3.i;
		ctemp.r = q__1.r, ctemp.i = q__1.i;
		i__4 = j + 1 + jc * h_dim1;
		r_cnjg(&q__4, &s);
		q__3.r = -q__4.r, q__3.i = -q__4.i;
		i__5 = j + jc * h_dim1;
		q__2.r = q__3.r * h__[i__5].r - q__3.i * h__[i__5].i, q__2.i =
			 q__3.r * h__[i__5].i + q__3.i * h__[i__5].r;
		i__6 = j + 1 + jc * h_dim1;
		q__5.r = c__ * h__[i__6].r, q__5.i = c__ * h__[i__6].i;
		q__1.r = q__2.r + q__5.r, q__1.i = q__2.i + q__5.i;
		h__[i__4].r = q__1.r, h__[i__4].i = q__1.i;
		i__4 = j + jc * h_dim1;
		h__[i__4].r = ctemp.r, h__[i__4].i = ctemp.i;
		i__4 = j + jc * t_dim1;
		q__2.r = c__ * t[i__4].r, q__2.i = c__ * t[i__4].i;
		i__5 = j + 1 + jc * t_dim1;
		q__3.r = s.r * t[i__5].r - s.i * t[i__5].i, q__3.i = s.r * t[
			i__5].i + s.i * t[i__5].r;
		q__1.r = q__2.r + q__3.r, q__1.i = q__2.i + q__3.i;
		ctemp2.r = q__1.r, ctemp2.i = q__1.i;
		i__4 = j + 1 + jc * t_dim1;
		r_cnjg(&q__4, &s);
		q__3.r = -q__4.r, q__3.i = -q__4.i;
		i__5 = j + jc * t_dim1;
		q__2.r = q__3.r * t[i__5].r - q__3.i * t[i__5].i, q__2.i = 
			q__3.r * t[i__5].i + q__3.i * t[i__5].r;
		i__6 = j + 1 + jc * t_dim1;
		q__5.r = c__ * t[i__6].r, q__5.i = c__ * t[i__6].i;
		q__1.r = q__2.r + q__5.r, q__1.i = q__2.i + q__5.i;
		t[i__4].r = q__1.r, t[i__4].i = q__1.i;
		i__4 = j + jc * t_dim1;
		t[i__4].r = ctemp2.r, t[i__4].i = ctemp2.i;
/* L100: */
	    }
	    if (ilq) {
		i__3 = *n;
		for (jr = 1; jr <= i__3; ++jr) {
		    i__4 = jr + j * q_dim1;
		    q__2.r = c__ * q[i__4].r, q__2.i = c__ * q[i__4].i;
		    r_cnjg(&q__4, &s);
		    i__5 = jr + (j + 1) * q_dim1;
		    q__3.r = q__4.r * q[i__5].r - q__4.i * q[i__5].i, q__3.i =
			     q__4.r * q[i__5].i + q__4.i * q[i__5].r;
		    q__1.r = q__2.r + q__3.r, q__1.i = q__2.i + q__3.i;
		    ctemp.r = q__1.r, ctemp.i = q__1.i;
		    i__4 = jr + (j + 1) * q_dim1;
		    q__3.r = -s.r, q__3.i = -s.i;
		    i__5 = jr + j * q_dim1;
		    q__2.r = q__3.r * q[i__5].r - q__3.i * q[i__5].i, q__2.i =
			     q__3.r * q[i__5].i + q__3.i * q[i__5].r;
		    i__6 = jr + (j + 1) * q_dim1;
		    q__4.r = c__ * q[i__6].r, q__4.i = c__ * q[i__6].i;
		    q__1.r = q__2.r + q__4.r, q__1.i = q__2.i + q__4.i;
		    q[i__4].r = q__1.r, q[i__4].i = q__1.i;
		    i__4 = jr + j * q_dim1;
		    q[i__4].r = ctemp.r, q[i__4].i = ctemp.i;
/* L110: */
		}
	    }

	    i__3 = j + 1 + (j + 1) * t_dim1;
	    ctemp.r = t[i__3].r, ctemp.i = t[i__3].i;
	    clartg_(&ctemp, &t[j + 1 + j * t_dim1], &c__, &s, &t[j + 1 + (j + 
		    1) * t_dim1]);
	    i__3 = j + 1 + j * t_dim1;
	    t[i__3].r = 0.f, t[i__3].i = 0.f;

/* Computing MIN */
	    i__4 = j + 2;
	    i__3 = MIN(i__4,ilast);
	    for (jr = ifrstm; jr <= i__3; ++jr) {
		i__4 = jr + (j + 1) * h_dim1;
		q__2.r = c__ * h__[i__4].r, q__2.i = c__ * h__[i__4].i;
		i__5 = jr + j * h_dim1;
		q__3.r = s.r * h__[i__5].r - s.i * h__[i__5].i, q__3.i = s.r *
			 h__[i__5].i + s.i * h__[i__5].r;
		q__1.r = q__2.r + q__3.r, q__1.i = q__2.i + q__3.i;
		ctemp.r = q__1.r, ctemp.i = q__1.i;
		i__4 = jr + j * h_dim1;
		r_cnjg(&q__4, &s);
		q__3.r = -q__4.r, q__3.i = -q__4.i;
		i__5 = jr + (j + 1) * h_dim1;
		q__2.r = q__3.r * h__[i__5].r - q__3.i * h__[i__5].i, q__2.i =
			 q__3.r * h__[i__5].i + q__3.i * h__[i__5].r;
		i__6 = jr + j * h_dim1;
		q__5.r = c__ * h__[i__6].r, q__5.i = c__ * h__[i__6].i;
		q__1.r = q__2.r + q__5.r, q__1.i = q__2.i + q__5.i;
		h__[i__4].r = q__1.r, h__[i__4].i = q__1.i;
		i__4 = jr + (j + 1) * h_dim1;
		h__[i__4].r = ctemp.r, h__[i__4].i = ctemp.i;
/* L120: */
	    }
	    i__3 = j;
	    for (jr = ifrstm; jr <= i__3; ++jr) {
		i__4 = jr + (j + 1) * t_dim1;
		q__2.r = c__ * t[i__4].r, q__2.i = c__ * t[i__4].i;
		i__5 = jr + j * t_dim1;
		q__3.r = s.r * t[i__5].r - s.i * t[i__5].i, q__3.i = s.r * t[
			i__5].i + s.i * t[i__5].r;
		q__1.r = q__2.r + q__3.r, q__1.i = q__2.i + q__3.i;
		ctemp.r = q__1.r, ctemp.i = q__1.i;
		i__4 = jr + j * t_dim1;
		r_cnjg(&q__4, &s);
		q__3.r = -q__4.r, q__3.i = -q__4.i;
		i__5 = jr + (j + 1) * t_dim1;
		q__2.r = q__3.r * t[i__5].r - q__3.i * t[i__5].i, q__2.i = 
			q__3.r * t[i__5].i + q__3.i * t[i__5].r;
		i__6 = jr + j * t_dim1;
		q__5.r = c__ * t[i__6].r, q__5.i = c__ * t[i__6].i;
		q__1.r = q__2.r + q__5.r, q__1.i = q__2.i + q__5.i;
		t[i__4].r = q__1.r, t[i__4].i = q__1.i;
		i__4 = jr + (j + 1) * t_dim1;
		t[i__4].r = ctemp.r, t[i__4].i = ctemp.i;
/* L130: */
	    }
	    if (ilz) {
		i__3 = *n;
		for (jr = 1; jr <= i__3; ++jr) {
		    i__4 = jr + (j + 1) * z_dim1;
		    q__2.r = c__ * z__[i__4].r, q__2.i = c__ * z__[i__4].i;
		    i__5 = jr + j * z_dim1;
		    q__3.r = s.r * z__[i__5].r - s.i * z__[i__5].i, q__3.i = 
			    s.r * z__[i__5].i + s.i * z__[i__5].r;
		    q__1.r = q__2.r + q__3.r, q__1.i = q__2.i + q__3.i;
		    ctemp.r = q__1.r, ctemp.i = q__1.i;
		    i__4 = jr + j * z_dim1;
		    r_cnjg(&q__4, &s);
		    q__3.r = -q__4.r, q__3.i = -q__4.i;
		    i__5 = jr + (j + 1) * z_dim1;
		    q__2.r = q__3.r * z__[i__5].r - q__3.i * z__[i__5].i, 
			    q__2.i = q__3.r * z__[i__5].i + q__3.i * z__[i__5]
			    .r;
		    i__6 = jr + j * z_dim1;
		    q__5.r = c__ * z__[i__6].r, q__5.i = c__ * z__[i__6].i;
		    q__1.r = q__2.r + q__5.r, q__1.i = q__2.i + q__5.i;
		    z__[i__4].r = q__1.r, z__[i__4].i = q__1.i;
		    i__4 = jr + (j + 1) * z_dim1;
		    z__[i__4].r = ctemp.r, z__[i__4].i = ctemp.i;
/* L140: */
		}
	    }
/* L150: */
	}

L160:

/* L170: */
	;
    }

/*     Drop-through = non-convergence */

L180:
    *info = ilast;
    goto L210;

/*     Successful completion of all QZ steps */

L190:

/*     Set Eigenvalues 1:ILO-1 */

    i__1 = *ilo - 1;
    for (j = 1; j <= i__1; ++j) {
	absb = c_abs(&t[j + j * t_dim1]);
	if (absb > safmin) {
	    i__2 = j + j * t_dim1;
	    q__2.r = t[i__2].r / absb, q__2.i = t[i__2].i / absb;
	    r_cnjg(&q__1, &q__2);
	    signbc.r = q__1.r, signbc.i = q__1.i;
	    i__2 = j + j * t_dim1;
	    t[i__2].r = absb, t[i__2].i = 0.f;
	    if (ilschr) {
		i__2 = j - 1;
		cscal_(&i__2, &signbc, &t[j * t_dim1 + 1], &c__1);
		cscal_(&j, &signbc, &h__[j * h_dim1 + 1], &c__1);
	    } else {
		i__2 = j + j * h_dim1;
		i__3 = j + j * h_dim1;
		q__1.r = h__[i__3].r * signbc.r - h__[i__3].i * signbc.i, 
			q__1.i = h__[i__3].r * signbc.i + h__[i__3].i * 
			signbc.r;
		h__[i__2].r = q__1.r, h__[i__2].i = q__1.i;
	    }
	    if (ilz) {
		cscal_(n, &signbc, &z__[j * z_dim1 + 1], &c__1);
	    }
	} else {
	    i__2 = j + j * t_dim1;
	    t[i__2].r = 0.f, t[i__2].i = 0.f;
	}
	i__2 = j;
	i__3 = j + j * h_dim1;
	alpha[i__2].r = h__[i__3].r, alpha[i__2].i = h__[i__3].i;
	i__2 = j;
	i__3 = j + j * t_dim1;
	beta[i__2].r = t[i__3].r, beta[i__2].i = t[i__3].i;
/* L200: */
    }

/*     Normal Termination */

    *info = 0;

/*     Exit (other than argument error) -- return optimal workspace size */

L210:
    q__1.r = (float) (*n), q__1.i = 0.f;
    work[1].r = q__1.r, work[1].i = q__1.i;
    return 0;

/*     End of CHGEQZ */

} /* chgeqz_ */
Esempio n. 2
0
/* Subroutine */ int chsein_(char *side, char *eigsrc, char *initv, logical *
	select, integer *n, complex *h__, integer *ldh, complex *w, complex *
	vl, integer *ldvl, complex *vr, integer *ldvr, integer *mm, integer *
	m, complex *work, real *rwork, integer *ifaill, integer *ifailr, 
	integer *info)
{
    /* System generated locals */
    integer h_dim1, h_offset, vl_dim1, vl_offset, vr_dim1, vr_offset, i__1, 
	    i__2, i__3;
    real r__1, r__2;
    complex q__1, q__2;

    /* Builtin functions */
    double r_imag(complex *);

    /* Local variables */
    integer i__, k, kl, kr, ks;
    complex wk;
    integer kln;
    real ulp, eps3, unfl;
    extern logical lsame_(char *, char *);
    integer iinfo;
    logical leftv, bothv;
    real hnorm;
    extern /* Subroutine */ int claein_(logical *, logical *, integer *, 
	    complex *, integer *, complex *, complex *, complex *, integer *, 
	    real *, real *, real *, integer *);
    extern doublereal slamch_(char *), clanhs_(char *, integer *, 
	    complex *, integer *, real *);
    extern /* Subroutine */ int xerbla_(char *, integer *);
    logical noinit;
    integer ldwork;
    logical rightv, fromqr;
    real smlnum;


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

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

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

/*  CHSEIN uses inverse iteration to find specified right and/or left */
/*  eigenvectors of a complex upper Hessenberg matrix H. */

/*  The right eigenvector x and the left eigenvector y of the matrix H */
/*  corresponding to an eigenvalue w are defined by: */

/*               H * x = w * x,     y**h * H = w * y**h */

/*  where y**h denotes the conjugate transpose of the vector y. */

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

/*  SIDE    (input) CHARACTER*1 */
/*          = 'R': compute right eigenvectors only; */
/*          = 'L': compute left eigenvectors only; */
/*          = 'B': compute both right and left eigenvectors. */

/*  EIGSRC  (input) CHARACTER*1 */
/*          Specifies the source of eigenvalues supplied in W: */
/*          = 'Q': the eigenvalues were found using CHSEQR; thus, if */
/*                 H has zero subdiagonal elements, and so is */
/*                 block-triangular, then the j-th eigenvalue can be */
/*                 assumed to be an eigenvalue of the block containing */
/*                 the j-th row/column.  This property allows CHSEIN to */
/*                 perform inverse iteration on just one diagonal block. */
/*          = 'N': no assumptions are made on the correspondence */
/*                 between eigenvalues and diagonal blocks.  In this */
/*                 case, CHSEIN must always perform inverse iteration */
/*                 using the whole matrix H. */

/*  INITV   (input) CHARACTER*1 */
/*          = 'N': no initial vectors are supplied; */
/*          = 'U': user-supplied initial vectors are stored in the arrays */
/*                 VL and/or VR. */

/*  SELECT  (input) LOGICAL array, dimension (N) */
/*          Specifies the eigenvectors to be computed. To select the */
/*          eigenvector corresponding to the eigenvalue W(j), */
/*          SELECT(j) must be set to .TRUE.. */

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

/*  H       (input) COMPLEX array, dimension (LDH,N) */
/*          The upper Hessenberg matrix H. */

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

/*  W       (input/output) COMPLEX array, dimension (N) */
/*          On entry, the eigenvalues of H. */
/*          On exit, the real parts of W may have been altered since */
/*          close eigenvalues are perturbed slightly in searching for */
/*          independent eigenvectors. */

/*  VL      (input/output) COMPLEX array, dimension (LDVL,MM) */
/*          On entry, if INITV = 'U' and SIDE = 'L' or 'B', VL must */
/*          contain starting vectors for the inverse iteration for the */
/*          left eigenvectors; the starting vector for each eigenvector */
/*          must be in the same column in which the eigenvector will be */
/*          stored. */
/*          On exit, if SIDE = 'L' or 'B', the left eigenvectors */
/*          specified by SELECT will be stored consecutively in the */
/*          columns of VL, in the same order as their eigenvalues. */
/*          If SIDE = 'R', VL is not referenced. */

/*  LDVL    (input) INTEGER */
/*          The leading dimension of the array VL. */
/*          LDVL >= max(1,N) if SIDE = 'L' or 'B'; LDVL >= 1 otherwise. */

/*  VR      (input/output) COMPLEX array, dimension (LDVR,MM) */
/*          On entry, if INITV = 'U' and SIDE = 'R' or 'B', VR must */
/*          contain starting vectors for the inverse iteration for the */
/*          right eigenvectors; the starting vector for each eigenvector */
/*          must be in the same column in which the eigenvector will be */
/*          stored. */
/*          On exit, if SIDE = 'R' or 'B', the right eigenvectors */
/*          specified by SELECT will be stored consecutively in the */
/*          columns of VR, in the same order as their eigenvalues. */
/*          If SIDE = 'L', VR is not referenced. */

/*  LDVR    (input) INTEGER */
/*          The leading dimension of the array VR. */
/*          LDVR >= max(1,N) if SIDE = 'R' or 'B'; LDVR >= 1 otherwise. */

/*  MM      (input) INTEGER */
/*          The number of columns in the arrays VL and/or VR. MM >= M. */

/*  M       (output) INTEGER */
/*          The number of columns in the arrays VL and/or VR required to */
/*          store the eigenvectors (= the number of .TRUE. elements in */
/*          SELECT). */

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

/*  RWORK   (workspace) REAL array, dimension (N) */

/*  IFAILL  (output) INTEGER array, dimension (MM) */
/*          If SIDE = 'L' or 'B', IFAILL(i) = j > 0 if the left */
/*          eigenvector in the i-th column of VL (corresponding to the */
/*          eigenvalue w(j)) failed to converge; IFAILL(i) = 0 if the */
/*          eigenvector converged satisfactorily. */
/*          If SIDE = 'R', IFAILL is not referenced. */

/*  IFAILR  (output) INTEGER array, dimension (MM) */
/*          If SIDE = 'R' or 'B', IFAILR(i) = j > 0 if the right */
/*          eigenvector in the i-th column of VR (corresponding to the */
/*          eigenvalue w(j)) failed to converge; IFAILR(i) = 0 if the */
/*          eigenvector converged satisfactorily. */
/*          If SIDE = 'L', IFAILR is not referenced. */

/*  INFO    (output) INTEGER */
/*          = 0:  successful exit */
/*          < 0:  if INFO = -i, the i-th argument had an illegal value */
/*          > 0:  if INFO = i, i is the number of eigenvectors which */
/*                failed to converge; see IFAILL and IFAILR for further */
/*                details. */

/*  Further Details */
/*  =============== */

/*  Each eigenvector is normalized so that the element of largest */
/*  magnitude has magnitude 1; here the magnitude of a complex number */
/*  (x,y) is taken to be |x|+|y|. */

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

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

/*     Decode and test the input parameters. */

    /* Parameter adjustments */
    --select;
    h_dim1 = *ldh;
    h_offset = 1 + h_dim1;
    h__ -= h_offset;
    --w;
    vl_dim1 = *ldvl;
    vl_offset = 1 + vl_dim1;
    vl -= vl_offset;
    vr_dim1 = *ldvr;
    vr_offset = 1 + vr_dim1;
    vr -= vr_offset;
    --work;
    --rwork;
    --ifaill;
    --ifailr;

    /* Function Body */
    bothv = lsame_(side, "B");
    rightv = lsame_(side, "R") || bothv;
    leftv = lsame_(side, "L") || bothv;

    fromqr = lsame_(eigsrc, "Q");

    noinit = lsame_(initv, "N");

/*     Set M to the number of columns required to store the selected */
/*     eigenvectors. */

    *m = 0;
    i__1 = *n;
    for (k = 1; k <= i__1; ++k) {
	if (select[k]) {
	    ++(*m);
	}
/* L10: */
    }

    *info = 0;
    if (! rightv && ! leftv) {
	*info = -1;
    } else if (! fromqr && ! lsame_(eigsrc, "N")) {
	*info = -2;
    } else if (! noinit && ! lsame_(initv, "U")) {
	*info = -3;
    } else if (*n < 0) {
	*info = -5;
    } else if (*ldh < max(1,*n)) {
	*info = -7;
    } else if (*ldvl < 1 || leftv && *ldvl < *n) {
	*info = -10;
    } else if (*ldvr < 1 || rightv && *ldvr < *n) {
	*info = -12;
    } else if (*mm < *m) {
	*info = -13;
    }
    if (*info != 0) {
	i__1 = -(*info);
	xerbla_("CHSEIN", &i__1);
	return 0;
    }

/*     Quick return if possible. */

    if (*n == 0) {
	return 0;
    }

/*     Set machine-dependent constants. */

    unfl = slamch_("Safe minimum");
    ulp = slamch_("Precision");
    smlnum = unfl * (*n / ulp);

    ldwork = *n;

    kl = 1;
    kln = 0;
    if (fromqr) {
	kr = 0;
    } else {
	kr = *n;
    }
    ks = 1;

    i__1 = *n;
    for (k = 1; k <= i__1; ++k) {
	if (select[k]) {

/*           Compute eigenvector(s) corresponding to W(K). */

	    if (fromqr) {

/*              If affiliation of eigenvalues is known, check whether */
/*              the matrix splits. */

/*              Determine KL and KR such that 1 <= KL <= K <= KR <= N */
/*              and H(KL,KL-1) and H(KR+1,KR) are zero (or KL = 1 or */
/*              KR = N). */

/*              Then inverse iteration can be performed with the */
/*              submatrix H(KL:N,KL:N) for a left eigenvector, and with */
/*              the submatrix H(1:KR,1:KR) for a right eigenvector. */

		i__2 = kl + 1;
		for (i__ = k; i__ >= i__2; --i__) {
		    i__3 = i__ + (i__ - 1) * h_dim1;
		    if (h__[i__3].r == 0.f && h__[i__3].i == 0.f) {
			goto L30;
		    }
/* L20: */
		}
L30:
		kl = i__;
		if (k > kr) {
		    i__2 = *n - 1;
		    for (i__ = k; i__ <= i__2; ++i__) {
			i__3 = i__ + 1 + i__ * h_dim1;
			if (h__[i__3].r == 0.f && h__[i__3].i == 0.f) {
			    goto L50;
			}
/* L40: */
		    }
L50:
		    kr = i__;
		}
	    }

	    if (kl != kln) {
		kln = kl;

/*              Compute infinity-norm of submatrix H(KL:KR,KL:KR) if it */
/*              has not ben computed before. */

		i__2 = kr - kl + 1;
		hnorm = clanhs_("I", &i__2, &h__[kl + kl * h_dim1], ldh, &
			rwork[1]);
		if (hnorm > 0.f) {
		    eps3 = hnorm * ulp;
		} else {
		    eps3 = smlnum;
		}
	    }

/*           Perturb eigenvalue if it is close to any previous */
/*           selected eigenvalues affiliated to the submatrix */
/*           H(KL:KR,KL:KR). Close roots are modified by EPS3. */

	    i__2 = k;
	    wk.r = w[i__2].r, wk.i = w[i__2].i;
L60:
	    i__2 = kl;
	    for (i__ = k - 1; i__ >= i__2; --i__) {
		i__3 = i__;
		q__2.r = w[i__3].r - wk.r, q__2.i = w[i__3].i - wk.i;
		q__1.r = q__2.r, q__1.i = q__2.i;
		if (select[i__] && (r__1 = q__1.r, dabs(r__1)) + (r__2 = 
			r_imag(&q__1), dabs(r__2)) < eps3) {
		    q__1.r = wk.r + eps3, q__1.i = wk.i;
		    wk.r = q__1.r, wk.i = q__1.i;
		    goto L60;
		}
/* L70: */
	    }
	    i__2 = k;
	    w[i__2].r = wk.r, w[i__2].i = wk.i;

	    if (leftv) {

/*              Compute left eigenvector. */

		i__2 = *n - kl + 1;
		claein_(&c_false, &noinit, &i__2, &h__[kl + kl * h_dim1], ldh, 
			 &wk, &vl[kl + ks * vl_dim1], &work[1], &ldwork, &
			rwork[1], &eps3, &smlnum, &iinfo);
		if (iinfo > 0) {
		    ++(*info);
		    ifaill[ks] = k;
		} else {
		    ifaill[ks] = 0;
		}
		i__2 = kl - 1;
		for (i__ = 1; i__ <= i__2; ++i__) {
		    i__3 = i__ + ks * vl_dim1;
		    vl[i__3].r = 0.f, vl[i__3].i = 0.f;
/* L80: */
		}
	    }
	    if (rightv) {

/*              Compute right eigenvector. */

		claein_(&c_true, &noinit, &kr, &h__[h_offset], ldh, &wk, &vr[
			ks * vr_dim1 + 1], &work[1], &ldwork, &rwork[1], &
			eps3, &smlnum, &iinfo);
		if (iinfo > 0) {
		    ++(*info);
		    ifailr[ks] = k;
		} else {
		    ifailr[ks] = 0;
		}
		i__2 = *n;
		for (i__ = kr + 1; i__ <= i__2; ++i__) {
		    i__3 = i__ + ks * vr_dim1;
		    vr[i__3].r = 0.f, vr[i__3].i = 0.f;
/* L90: */
		}
	    }
	    ++ks;
	}
/* L100: */
    }

    return 0;

/*     End of CHSEIN */

} /* chsein_ */
Esempio n. 3
0
/* Subroutine */ int chseqr_(char *job, char *compz, integer *n, integer *ilo,
	 integer *ihi, complex *h__, integer *ldh, complex *w, complex *z__, 
	integer *ldz, complex *work, integer *lwork, integer *info)
{
    /* System generated locals */
    address a__1[2];
    integer h_dim1, h_offset, z_dim1, z_offset, i__1, i__2, i__3, i__4[2], 
	    i__5, i__6;
    real r__1, r__2, r__3, r__4;
    complex q__1;
    char ch__1[2];

    /* Builtin functions */
    double r_imag(complex *);
    void r_cnjg(complex *, complex *);
    /* Subroutine */ int s_cat(char *, char **, integer *, integer *, ftnlen);

    /* Local variables */
    static integer maxb, ierr;
    static real unfl;
    static complex temp;
    static real ovfl, opst;
    static integer i__, j, k, l;
    static complex s[225]	/* was [15][15] */;
    extern /* Subroutine */ int cscal_(integer *, complex *, complex *, 
	    integer *);
    static complex v[16];
    extern logical lsame_(char *, char *);
    extern /* Subroutine */ int cgemv_(char *, integer *, integer *, complex *
	    , complex *, integer *, complex *, integer *, complex *, complex *
	    , integer *), ccopy_(integer *, complex *, integer *, 
	    complex *, integer *);
    static integer itemp;
    static real rtemp;
    static integer i1, i2;
    static logical initz, wantt, wantz;
    static real rwork[1];
    extern doublereal slapy2_(real *, real *);
    static integer ii, nh;
    extern /* Subroutine */ int slabad_(real *, real *), clarfg_(integer *, 
	    complex *, complex *, integer *, complex *);
    static integer nr, ns;
    extern integer icamax_(integer *, complex *, integer *);
    static integer nv;
    extern doublereal slamch_(char *), clanhs_(char *, integer *, 
	    complex *, integer *, real *);
    extern /* Subroutine */ int csscal_(integer *, real *, complex *, integer 
	    *), clahqr_(logical *, logical *, integer *, integer *, integer *,
	     complex *, integer *, complex *, integer *, integer *, complex *,
	     integer *, integer *), clacpy_(char *, integer *, integer *, 
	    complex *, integer *, complex *, integer *);
    static complex vv[16];
    extern /* Subroutine */ int claset_(char *, integer *, integer *, complex 
	    *, complex *, complex *, integer *);
    extern integer ilaenv_(integer *, char *, char *, integer *, integer *, 
	    integer *, integer *, ftnlen, ftnlen);
    extern /* Subroutine */ int clarfx_(char *, integer *, integer *, complex 
	    *, complex *, complex *, integer *, complex *), xerbla_(
	    char *, integer *);
    static real smlnum;
    static logical lquery;
    static integer itn;
    static complex tau;
    static integer its;
    static real ulp, tst1;


#define h___subscr(a_1,a_2) (a_2)*h_dim1 + a_1
#define h___ref(a_1,a_2) h__[h___subscr(a_1,a_2)]
#define s_subscr(a_1,a_2) (a_2)*15 + a_1 - 16
#define s_ref(a_1,a_2) s[s_subscr(a_1,a_2)]
#define z___subscr(a_1,a_2) (a_2)*z_dim1 + a_1
#define z___ref(a_1,a_2) z__[z___subscr(a_1,a_2)]


/*  -- LAPACK routine (instrumented to count operations, version 3.0) --   
       Univ. of Tennessee, Univ. of California Berkeley, NAG Ltd.,   
       Courant Institute, Argonne National Lab, and Rice University   
       June 30, 1999   

       Common block to return operation count.   

    Purpose   
    =======   

    CHSEQR computes the eigenvalues of a complex upper Hessenberg   
    matrix H, and, optionally, the matrices T and Z from the Schur   
    decomposition H = Z T Z**H, where T is an upper triangular matrix   
    (the Schur form), and Z is the unitary matrix of Schur vectors.   

    Optionally Z may be postmultiplied into an input unitary matrix Q,   
    so that this routine can give the Schur factorization of a matrix A   
    which has been reduced to the Hessenberg form H by the unitary   
    matrix Q:  A = Q*H*Q**H = (QZ)*T*(QZ)**H.   

    Arguments   
    =========   

    JOB     (input) CHARACTER*1   
            = 'E': compute eigenvalues only;   
            = 'S': compute eigenvalues and the Schur form T.   

    COMPZ   (input) CHARACTER*1   
            = 'N': no Schur vectors are computed;   
            = 'I': Z is initialized to the unit matrix and the matrix Z   
                   of Schur vectors of H is returned;   
            = 'V': Z must contain an unitary matrix Q on entry, and   
                   the product Q*Z is returned.   

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

    ILO     (input) INTEGER   
    IHI     (input) INTEGER   
            It is assumed that H is already upper triangular in rows   
            and columns 1:ILO-1 and IHI+1:N. ILO and IHI are normally   
            set by a previous call to CGEBAL, and then passed to CGEHRD   
            when the matrix output by CGEBAL is reduced to Hessenberg   
            form. Otherwise ILO and IHI should be set to 1 and N   
            respectively.   
            1 <= ILO <= IHI <= N, if N > 0; ILO=1 and IHI=0, if N=0.   

    H       (input/output) COMPLEX array, dimension (LDH,N)   
            On entry, the upper Hessenberg matrix H.   
            On exit, if JOB = 'S', H contains the upper triangular matrix   
            T from the Schur decomposition (the Schur form). If   
            JOB = 'E', the contents of H are unspecified on exit.   

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

    W       (output) COMPLEX array, dimension (N)   
            The computed eigenvalues. If JOB = 'S', the eigenvalues are   
            stored in the same order as on the diagonal of the Schur form   
            returned in H, with W(i) = H(i,i).   

    Z       (input/output) COMPLEX array, dimension (LDZ,N)   
            If COMPZ = 'N': Z is not referenced.   
            If COMPZ = 'I': on entry, Z need not be set, and on exit, Z   
            contains the unitary matrix Z of the Schur vectors of H.   
            If COMPZ = 'V': on entry Z must contain an N-by-N matrix Q,   
            which is assumed to be equal to the unit matrix except for   
            the submatrix Z(ILO:IHI,ILO:IHI); on exit Z contains Q*Z.   
            Normally Q is the unitary matrix generated by CUNGHR after   
            the call to CGEHRD which formed the Hessenberg matrix H.   

    LDZ     (input) INTEGER   
            The leading dimension of the array Z.   
            LDZ >= max(1,N) if COMPZ = 'I' or 'V'; LDZ >= 1 otherwise.   

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

    LWORK   (input) INTEGER   
            The dimension of the array WORK.  LWORK >= max(1,N).   

            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, CHSEQR failed to compute all the   
                  eigenvalues in a total of 30*(IHI-ILO+1) iterations;   
                  elements 1:ilo-1 and i+1:n of W contain those   
                  eigenvalues which have been successfully computed.   

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


       Decode and test the input parameters   

       Parameter adjustments */
    h_dim1 = *ldh;
    h_offset = 1 + h_dim1 * 1;
    h__ -= h_offset;
    --w;
    z_dim1 = *ldz;
    z_offset = 1 + z_dim1 * 1;
    z__ -= z_offset;
    --work;

    /* Function Body */
    wantt = lsame_(job, "S");
    initz = lsame_(compz, "I");
    wantz = initz || lsame_(compz, "V");

    *info = 0;
    i__1 = max(1,*n);
    work[1].r = (real) i__1, work[1].i = 0.f;
    lquery = *lwork == -1;
    if (! lsame_(job, "E") && ! wantt) {
	*info = -1;
    } else if (! lsame_(compz, "N") && ! wantz) {
	*info = -2;
    } else if (*n < 0) {
	*info = -3;
    } else if (*ilo < 1 || *ilo > max(1,*n)) {
	*info = -4;
    } else if (*ihi < min(*ilo,*n) || *ihi > *n) {
	*info = -5;
    } else if (*ldh < max(1,*n)) {
	*info = -7;
    } else if (*ldz < 1 || wantz && *ldz < max(1,*n)) {
	*info = -10;
    } else if (*lwork < max(1,*n) && ! lquery) {
	*info = -12;
    }
    if (*info != 0) {
	i__1 = -(*info);
	xerbla_("CHSEQR", &i__1);
	return 0;
    } else if (lquery) {
	return 0;
    }
/* **   
       Initialize */
    opst = 0.f;
/* **   

       Initialize Z, if necessary */

    if (initz) {
	claset_("Full", n, n, &c_b1, &c_b2, &z__[z_offset], ldz);
    }

/*     Store the eigenvalues isolated by CGEBAL. */

    i__1 = *ilo - 1;
    for (i__ = 1; i__ <= i__1; ++i__) {
	i__2 = i__;
	i__3 = h___subscr(i__, i__);
	w[i__2].r = h__[i__3].r, w[i__2].i = h__[i__3].i;
/* L10: */
    }
    i__1 = *n;
    for (i__ = *ihi + 1; i__ <= i__1; ++i__) {
	i__2 = i__;
	i__3 = h___subscr(i__, i__);
	w[i__2].r = h__[i__3].r, w[i__2].i = h__[i__3].i;
/* L20: */
    }

/*     Quick return if possible. */

    if (*n == 0) {
	return 0;
    }
    if (*ilo == *ihi) {
	i__1 = *ilo;
	i__2 = h___subscr(*ilo, *ilo);
	w[i__1].r = h__[i__2].r, w[i__1].i = h__[i__2].i;
	return 0;
    }

/*     Set rows and columns ILO to IHI to zero below the first   
       subdiagonal. */

    i__1 = *ihi - 2;
    for (j = *ilo; j <= i__1; ++j) {
	i__2 = *n;
	for (i__ = j + 2; i__ <= i__2; ++i__) {
	    i__3 = h___subscr(i__, j);
	    h__[i__3].r = 0.f, h__[i__3].i = 0.f;
/* L30: */
	}
/* L40: */
    }
    nh = *ihi - *ilo + 1;

/*     I1 and I2 are the indices of the first row and last column of H   
       to which transformations must be applied. If eigenvalues only are   
       being computed, I1 and I2 are re-set inside the main loop. */

    if (wantt) {
	i1 = 1;
	i2 = *n;
    } else {
	i1 = *ilo;
	i2 = *ihi;
    }

/*     Ensure that the subdiagonal elements are real. */

    i__1 = *ihi;
    for (i__ = *ilo + 1; i__ <= i__1; ++i__) {
	i__2 = h___subscr(i__, i__ - 1);
	temp.r = h__[i__2].r, temp.i = h__[i__2].i;
	if (r_imag(&temp) != 0.f) {
	    r__1 = temp.r;
	    r__2 = r_imag(&temp);
	    rtemp = slapy2_(&r__1, &r__2);
	    i__2 = h___subscr(i__, i__ - 1);
	    h__[i__2].r = rtemp, h__[i__2].i = 0.f;
	    q__1.r = temp.r / rtemp, q__1.i = temp.i / rtemp;
	    temp.r = q__1.r, temp.i = q__1.i;
	    if (i2 > i__) {
		i__2 = i2 - i__;
		r_cnjg(&q__1, &temp);
		cscal_(&i__2, &q__1, &h___ref(i__, i__ + 1), ldh);
	    }
	    i__2 = i__ - i1;
	    cscal_(&i__2, &temp, &h___ref(i1, i__), &c__1);
	    if (i__ < *ihi) {
		i__2 = h___subscr(i__ + 1, i__);
		i__3 = h___subscr(i__ + 1, i__);
		q__1.r = temp.r * h__[i__3].r - temp.i * h__[i__3].i, q__1.i =
			 temp.r * h__[i__3].i + temp.i * h__[i__3].r;
		h__[i__2].r = q__1.r, h__[i__2].i = q__1.i;
	    }
/* **   
             Increment op count */
	    opst += (i2 - i1 + 2) * 6;
/* ** */
	    if (wantz) {
		cscal_(&nh, &temp, &z___ref(*ilo, i__), &c__1);
/* **   
                Increment op count */
		opst += nh * 6;
/* ** */
	    }
	}
/* L50: */
    }

/*     Determine the order of the multi-shift QR algorithm to be used.   

   Writing concatenation */
    i__4[0] = 1, a__1[0] = job;
    i__4[1] = 1, a__1[1] = compz;
    s_cat(ch__1, a__1, i__4, &c__2, (ftnlen)2);
    ns = ilaenv_(&c__4, "CHSEQR", ch__1, n, ilo, ihi, &c_n1, (ftnlen)6, (
	    ftnlen)2);
/* Writing concatenation */
    i__4[0] = 1, a__1[0] = job;
    i__4[1] = 1, a__1[1] = compz;
    s_cat(ch__1, a__1, i__4, &c__2, (ftnlen)2);
    maxb = ilaenv_(&c__8, "CHSEQR", ch__1, n, ilo, ihi, &c_n1, (ftnlen)6, (
	    ftnlen)2);
    if (ns <= 1 || ns > nh || maxb >= nh) {

/*        Use the standard double-shift algorithm */

	clahqr_(&wantt, &wantz, n, ilo, ihi, &h__[h_offset], ldh, &w[1], ilo, 
		ihi, &z__[z_offset], ldz, info);
	return 0;
    }
    maxb = max(2,maxb);
/* Computing MIN */
    i__1 = min(ns,maxb);
    ns = min(i__1,15);

/*     Now 1 < NS <= MAXB < NH.   

       Set machine-dependent constants for the stopping criterion.   
       If norm(H) <= sqrt(OVFL), overflow should not occur. */

    unfl = slamch_("Safe minimum");
    ovfl = 1.f / unfl;
    slabad_(&unfl, &ovfl);
    ulp = slamch_("Precision");
    smlnum = unfl * (nh / ulp);

/*     ITN is the total number of multiple-shift QR iterations allowed. */

    itn = nh * 30;

/*     The main loop begins here. I is the loop index and decreases from   
       IHI to ILO in steps of at most MAXB. Each iteration of the loop   
       works with the active submatrix in rows and columns L to I.   
       Eigenvalues I+1 to IHI have already converged. Either L = ILO, or   
       H(L,L-1) is negligible so that the matrix splits. */

    i__ = *ihi;
L60:
    if (i__ < *ilo) {
	goto L180;
    }

/*     Perform multiple-shift QR iterations on rows and columns ILO to I   
       until a submatrix of order at most MAXB splits off at the bottom   
       because a subdiagonal element has become negligible. */

    l = *ilo;
    i__1 = itn;
    for (its = 0; its <= i__1; ++its) {

/*        Look for a single small subdiagonal element. */

	i__2 = l + 1;
	for (k = i__; k >= i__2; --k) {
	    i__3 = h___subscr(k - 1, k - 1);
	    i__5 = h___subscr(k, k);
	    tst1 = (r__1 = h__[i__3].r, dabs(r__1)) + (r__2 = r_imag(&h___ref(
		    k - 1, k - 1)), dabs(r__2)) + ((r__3 = h__[i__5].r, dabs(
		    r__3)) + (r__4 = r_imag(&h___ref(k, k)), dabs(r__4)));
	    if (tst1 == 0.f) {
		i__3 = i__ - l + 1;
		tst1 = clanhs_("1", &i__3, &h___ref(l, l), ldh, rwork);
/* **   
                Increment op count */
		latime_1.ops += (i__ - l + 1) * 5 * (i__ - l) / 2;
/* ** */
	    }
	    i__3 = h___subscr(k, k - 1);
/* Computing MAX */
	    r__2 = ulp * tst1;
	    if ((r__1 = h__[i__3].r, dabs(r__1)) <= dmax(r__2,smlnum)) {
		goto L80;
	    }
/* L70: */
	}
L80:
	l = k;
/* **   
          Increment op count */
	opst += (i__ - l + 1) * 5;
/* ** */
	if (l > *ilo) {

/*           H(L,L-1) is negligible. */

	    i__2 = h___subscr(l, l - 1);
	    h__[i__2].r = 0.f, h__[i__2].i = 0.f;
	}

/*        Exit from loop if a submatrix of order <= MAXB has split off. */

	if (l >= i__ - maxb + 1) {
	    goto L170;
	}

/*        Now the active submatrix is in rows and columns L to I. If   
          eigenvalues only are being computed, only the active submatrix   
          need be transformed. */

	if (! wantt) {
	    i1 = l;
	    i2 = i__;
	}

	if (its == 20 || its == 30) {

/*           Exceptional shifts. */

	    i__2 = i__;
	    for (ii = i__ - ns + 1; ii <= i__2; ++ii) {
		i__3 = ii;
		i__5 = h___subscr(ii, ii - 1);
		i__6 = h___subscr(ii, ii);
		r__3 = ((r__1 = h__[i__5].r, dabs(r__1)) + (r__2 = h__[i__6]
			.r, dabs(r__2))) * 1.5f;
		w[i__3].r = r__3, w[i__3].i = 0.f;
/* L90: */
	    }
/* **   
             Increment op count */
	    opst += ns << 1;
/* ** */
	} else {

/*           Use eigenvalues of trailing submatrix of order NS as shifts. */

	    clacpy_("Full", &ns, &ns, &h___ref(i__ - ns + 1, i__ - ns + 1), 
		    ldh, s, &c__15);
	    clahqr_(&c_false, &c_false, &ns, &c__1, &ns, s, &c__15, &w[i__ - 
		    ns + 1], &c__1, &ns, &z__[z_offset], ldz, &ierr);
	    if (ierr > 0) {

/*              If CLAHQR failed to compute all NS eigenvalues, use the   
                unconverged diagonal elements as the remaining shifts. */

		i__2 = ierr;
		for (ii = 1; ii <= i__2; ++ii) {
		    i__3 = i__ - ns + ii;
		    i__5 = s_subscr(ii, ii);
		    w[i__3].r = s[i__5].r, w[i__3].i = s[i__5].i;
/* L100: */
		}
	    }
	}

/*        Form the first column of (G-w(1)) (G-w(2)) . . . (G-w(ns))   
          where G is the Hessenberg submatrix H(L:I,L:I) and w is   
          the vector of shifts (stored in W). The result is   
          stored in the local array V. */

	v[0].r = 1.f, v[0].i = 0.f;
	i__2 = ns + 1;
	for (ii = 2; ii <= i__2; ++ii) {
	    i__3 = ii - 1;
	    v[i__3].r = 0.f, v[i__3].i = 0.f;
/* L110: */
	}
	nv = 1;
	i__2 = i__;
	for (j = i__ - ns + 1; j <= i__2; ++j) {
	    i__3 = nv + 1;
	    ccopy_(&i__3, v, &c__1, vv, &c__1);
	    i__3 = nv + 1;
	    i__5 = j;
	    q__1.r = -w[i__5].r, q__1.i = -w[i__5].i;
	    cgemv_("No transpose", &i__3, &nv, &c_b2, &h___ref(l, l), ldh, vv,
		     &c__1, &q__1, v, &c__1);
	    ++nv;
/* **   
             Increment op count */
	    opst = opst + (nv << 3) * (*n + 1) + (nv + 1) * 6;
/* **   

             Scale V(1:NV) so that max(abs(V(i))) = 1. If V is zero,   
             reset it to the unit vector. */

	    itemp = icamax_(&nv, v, &c__1);
/* **   
             Increment op count */
	    opst += nv << 1;
/* ** */
	    i__3 = itemp - 1;
	    rtemp = (r__1 = v[i__3].r, dabs(r__1)) + (r__2 = r_imag(&v[itemp 
		    - 1]), dabs(r__2));
	    if (rtemp == 0.f) {
		v[0].r = 1.f, v[0].i = 0.f;
		i__3 = nv;
		for (ii = 2; ii <= i__3; ++ii) {
		    i__5 = ii - 1;
		    v[i__5].r = 0.f, v[i__5].i = 0.f;
/* L120: */
		}
	    } else {
		rtemp = dmax(rtemp,smlnum);
		r__1 = 1.f / rtemp;
		csscal_(&nv, &r__1, v, &c__1);
/* **   
                Increment op count */
		opst += nv << 1;
/* ** */
	    }
/* L130: */
	}

/*        Multiple-shift QR step */

	i__2 = i__ - 1;
	for (k = l; k <= i__2; ++k) {

/*           The first iteration of this loop determines a reflection G   
             from the vector V and applies it from left and right to H,   
             thus creating a nonzero bulge below the subdiagonal.   

             Each subsequent iteration determines a reflection G to   
             restore the Hessenberg form in the (K-1)th column, and thus   
             chases the bulge one step toward the bottom of the active   
             submatrix. NR is the order of G.   

   Computing MIN */
	    i__3 = ns + 1, i__5 = i__ - k + 1;
	    nr = min(i__3,i__5);
	    if (k > l) {
		ccopy_(&nr, &h___ref(k, k - 1), &c__1, v, &c__1);
	    }
	    clarfg_(&nr, v, &v[1], &c__1, &tau);
/* **   
             Increment op count */
	    opst = opst + nr * 10 + 12;
/* ** */
	    if (k > l) {
		i__3 = h___subscr(k, k - 1);
		h__[i__3].r = v[0].r, h__[i__3].i = v[0].i;
		i__3 = i__;
		for (ii = k + 1; ii <= i__3; ++ii) {
		    i__5 = h___subscr(ii, k - 1);
		    h__[i__5].r = 0.f, h__[i__5].i = 0.f;
/* L140: */
		}
	    }
	    v[0].r = 1.f, v[0].i = 0.f;

/*           Apply G' from the left to transform the rows of the matrix   
             in columns K to I2. */

	    i__3 = i2 - k + 1;
	    r_cnjg(&q__1, &tau);
	    clarfx_("Left", &nr, &i__3, v, &q__1, &h___ref(k, k), ldh, &work[
		    1]);

/*           Apply G from the right to transform the columns of the   
             matrix in rows I1 to min(K+NR,I).   

   Computing MIN */
	    i__5 = k + nr;
	    i__3 = min(i__5,i__) - i1 + 1;
	    clarfx_("Right", &i__3, &nr, v, &tau, &h___ref(i1, k), ldh, &work[
		    1]);
/* **   
             Increment op count   
   Computing MIN */
	    i__3 = nr, i__5 = i__ - k;
	    latime_1.ops += ((nr << 2) - 2 << 2) * (i2 - i1 + 2 + min(i__3,
		    i__5));
/* ** */

	    if (wantz) {

/*              Accumulate transformations in the matrix Z */

		clarfx_("Right", &nh, &nr, v, &tau, &z___ref(*ilo, k), ldz, &
			work[1]);
/* **   
                Increment op count */
		latime_1.ops += ((nr << 2) - 2 << 2) * nh;
/* ** */
	    }
/* L150: */
	}

/*        Ensure that H(I,I-1) is real. */

	i__2 = h___subscr(i__, i__ - 1);
	temp.r = h__[i__2].r, temp.i = h__[i__2].i;
	if (r_imag(&temp) != 0.f) {
	    r__1 = temp.r;
	    r__2 = r_imag(&temp);
	    rtemp = slapy2_(&r__1, &r__2);
	    i__2 = h___subscr(i__, i__ - 1);
	    h__[i__2].r = rtemp, h__[i__2].i = 0.f;
	    q__1.r = temp.r / rtemp, q__1.i = temp.i / rtemp;
	    temp.r = q__1.r, temp.i = q__1.i;
	    if (i2 > i__) {
		i__2 = i2 - i__;
		r_cnjg(&q__1, &temp);
		cscal_(&i__2, &q__1, &h___ref(i__, i__ + 1), ldh);
	    }
	    i__2 = i__ - i1;
	    cscal_(&i__2, &temp, &h___ref(i1, i__), &c__1);
/* **   
             Increment op count */
	    opst += (i2 - i1 + 1) * 6;
/* ** */
	    if (wantz) {
		cscal_(&nh, &temp, &z___ref(*ilo, i__), &c__1);
/* **   
                Increment op count */
		opst += nh * 6;
/* ** */
	    }
	}

/* L160: */
    }

/*     Failure to converge in remaining number of iterations */

    *info = i__;
    return 0;

L170:

/*     A submatrix of order <= MAXB in rows and columns L to I has split   
       off. Use the double-shift QR algorithm to handle it. */

    clahqr_(&wantt, &wantz, n, &l, &i__, &h__[h_offset], ldh, &w[1], ilo, ihi,
	     &z__[z_offset], ldz, info);
    if (*info > 0) {
	return 0;
    }

/*     Decrement number of remaining iterations, and return to start of   
       the main loop with a new value of I. */

    itn -= its;
    i__ = l - 1;
    goto L60;

L180:
/* **   
       Compute final op count */
    latime_1.ops += opst;
/* ** */
    i__1 = max(1,*n);
    work[1].r = (real) i__1, work[1].i = 0.f;
    return 0;

/*     End of CHSEQR */

} /* chseqr_ */
Esempio n. 4
0
/* Subroutine */ int cnapps_(integer *n, integer *kev, integer *np, complex *
	shift, complex *v, integer *ldv, complex *h__, integer *ldh, complex *
	resid, complex *q, integer *ldq, complex *workl, complex *workd)
{
    /* Initialized data */

    static logical first = TRUE_;

    /* System generated locals */
    integer h_dim1, h_offset, v_dim1, v_offset, q_dim1, q_offset, i__1, i__2, 
	    i__3, i__4, i__5, i__6;
    real r__1, r__2, r__3, r__4;
    complex q__1, q__2, q__3, q__4, q__5;

    /* Builtin functions */
    double r_imag(complex *);
    void r_cnjg(complex *, complex *);

    /* Local variables */
    static real c__;
    static complex f, g;
    static integer i__, j;
    static complex r__, s, t;
    static real t0, t1;
    static complex h11, h21;
    static integer jj;
    static real ulp, tst1;
    static integer iend;
    static real unfl, ovfl;
    extern /* Subroutine */ int cscal_(integer *, complex *, complex *, 
	    integer *);
    static complex sigma;
    extern /* Subroutine */ int cgemv_(char *, integer *, integer *, complex *
	    , complex *, integer *, complex *, integer *, complex *, complex *
	    , integer *, ftnlen), ccopy_(integer *, complex *, integer *, 
	    complex *, integer *), caxpy_(integer *, complex *, complex *, 
	    integer *, complex *, integer *), cmout_(integer *, integer *, 
	    integer *, complex *, integer *, integer *, char *, ftnlen), 
	    cvout_(integer *, integer *, complex *, integer *, char *, ftnlen)
	    , ivout_(integer *, integer *, integer *, integer *, char *, 
	    ftnlen);
    extern doublereal slapy2_(real *, real *);
    extern /* Subroutine */ int slabad_(real *, real *);
    extern doublereal clanhs_(char *, integer *, complex *, integer *, 
	    complex *, ftnlen), slamch_(char *, ftnlen);
    extern /* Subroutine */ int clacpy_(char *, integer *, integer *, complex 
	    *, integer *, complex *, integer *, ftnlen);
    static integer istart, kplusp, msglvl;
    static real smlnum;
    extern /* Subroutine */ int clartg_(complex *, complex *, real *, complex 
	    *, complex *), claset_(char *, integer *, integer *, complex *, 
	    complex *, complex *, integer *, ftnlen), second_(real *);


/*     %----------------------------------------------------% */
/*     | Include files for debugging and timing information | */
/*     %----------------------------------------------------% */


/* \SCCS Information: @(#) */
/* FILE: debug.h   SID: 2.3   DATE OF SID: 11/16/95   RELEASE: 2 */

/*     %---------------------------------% */
/*     | See debug.doc for documentation | */
/*     %---------------------------------% */

/*     %------------------% */
/*     | Scalar Arguments | */
/*     %------------------% */

/*     %--------------------------------% */
/*     | See stat.doc for documentation | */
/*     %--------------------------------% */

/* \SCCS Information: @(#) */
/* FILE: stat.h   SID: 2.2   DATE OF SID: 11/16/95   RELEASE: 2 */



/*     %-----------------% */
/*     | Array Arguments | */
/*     %-----------------% */


/*     %------------% */
/*     | Parameters | */
/*     %------------% */


/*     %------------------------% */
/*     | Local Scalars & Arrays | */
/*     %------------------------% */


/*     %----------------------% */
/*     | External Subroutines | */
/*     %----------------------% */


/*     %--------------------% */
/*     | External Functions | */
/*     %--------------------% */


/*     %----------------------% */
/*     | Intrinsics Functions | */
/*     %----------------------% */


/*     %---------------------% */
/*     | Statement Functions | */
/*     %---------------------% */


/*     %----------------% */
/*     | Data statments | */
/*     %----------------% */

    /* Parameter adjustments */
    --workd;
    --resid;
    --workl;
    --shift;
    v_dim1 = *ldv;
    v_offset = 1 + v_dim1;
    v -= v_offset;
    h_dim1 = *ldh;
    h_offset = 1 + h_dim1;
    h__ -= h_offset;
    q_dim1 = *ldq;
    q_offset = 1 + q_dim1;
    q -= q_offset;

    /* Function Body */

/*     %-----------------------% */
/*     | Executable Statements | */
/*     %-----------------------% */

    if (first) {

/*        %-----------------------------------------------% */
/*        | Set machine-dependent constants for the       | */
/*        | stopping criterion. If norm(H) <= sqrt(OVFL), | */
/*        | overflow should not occur.                    | */
/*        | REFERENCE: LAPACK subroutine clahqr           | */
/*        %-----------------------------------------------% */

	unfl = slamch_("safe minimum", (ftnlen)12);
	q__1.r = 1.f / unfl, q__1.i = 0.f / unfl;
	ovfl = q__1.r;
	slabad_(&unfl, &ovfl);
	ulp = slamch_("precision", (ftnlen)9);
	smlnum = unfl * (*n / ulp);
	first = FALSE_;
    }

/*     %-------------------------------% */
/*     | Initialize timing statistics  | */
/*     | & message level for debugging | */
/*     %-------------------------------% */

    second_(&t0);
    msglvl = debug_1.mcapps;

    kplusp = *kev + *np;

/*     %--------------------------------------------% */
/*     | Initialize Q to the identity to accumulate | */
/*     | the rotations and reflections              | */
/*     %--------------------------------------------% */

    claset_("All", &kplusp, &kplusp, &c_b2, &c_b1, &q[q_offset], ldq, (ftnlen)
	    3);

/*     %----------------------------------------------% */
/*     | Quick return if there are no shifts to apply | */
/*     %----------------------------------------------% */

    if (*np == 0) {
	goto L9000;
    }

/*     %----------------------------------------------% */
/*     | Chase the bulge with the application of each | */
/*     | implicit shift. Each shift is applied to the | */
/*     | whole matrix including each block.           | */
/*     %----------------------------------------------% */

    i__1 = *np;
    for (jj = 1; jj <= i__1; ++jj) {
	i__2 = jj;
	sigma.r = shift[i__2].r, sigma.i = shift[i__2].i;

	if (msglvl > 2) {
	    ivout_(&debug_1.logfil, &c__1, &jj, &debug_1.ndigit, "_napps: sh"
		    "ift number.", (ftnlen)21);
	    cvout_(&debug_1.logfil, &c__1, &sigma, &debug_1.ndigit, "_napps:"
		    " Value of the shift ", (ftnlen)27);
	}

	istart = 1;
L20:

	i__2 = kplusp - 1;
	for (i__ = istart; i__ <= i__2; ++i__) {

/*           %----------------------------------------% */
/*           | Check for splitting and deflation. Use | */
/*           | a standard test as in the QR algorithm | */
/*           | REFERENCE: LAPACK subroutine clahqr    | */
/*           %----------------------------------------% */

	    i__3 = i__ + i__ * h_dim1;
	    i__4 = i__ + 1 + (i__ + 1) * h_dim1;
	    tst1 = (r__1 = h__[i__3].r, dabs(r__1)) + (r__2 = r_imag(&h__[i__ 
		    + i__ * h_dim1]), dabs(r__2)) + ((r__3 = h__[i__4].r, 
		    dabs(r__3)) + (r__4 = r_imag(&h__[i__ + 1 + (i__ + 1) * 
		    h_dim1]), dabs(r__4)));
	    if (tst1 == 0.f) {
		i__3 = kplusp - jj + 1;
		tst1 = clanhs_("1", &i__3, &h__[h_offset], ldh, &workl[1], (
			ftnlen)1);
	    }
	    i__3 = i__ + 1 + i__ * h_dim1;
/* Computing MAX */
	    r__2 = ulp * tst1;
	    if ((r__1 = h__[i__3].r, dabs(r__1)) <= dmax(r__2,smlnum)) {
		if (msglvl > 0) {
		    ivout_(&debug_1.logfil, &c__1, &i__, &debug_1.ndigit, 
			    "_napps: matrix splitting at row/column no.", (
			    ftnlen)42);
		    ivout_(&debug_1.logfil, &c__1, &jj, &debug_1.ndigit, 
			    "_napps: matrix splitting with shift number.", (
			    ftnlen)43);
		    cvout_(&debug_1.logfil, &c__1, &h__[i__ + 1 + i__ * 
			    h_dim1], &debug_1.ndigit, "_napps: off diagonal "
			    "element.", (ftnlen)29);
		}
		iend = i__;
		i__3 = i__ + 1 + i__ * h_dim1;
		h__[i__3].r = 0.f, h__[i__3].i = 0.f;
		goto L40;
	    }
/* L30: */
	}
	iend = kplusp;
L40:

	if (msglvl > 2) {
	    ivout_(&debug_1.logfil, &c__1, &istart, &debug_1.ndigit, "_napps"
		    ": Start of current block ", (ftnlen)31);
	    ivout_(&debug_1.logfil, &c__1, &iend, &debug_1.ndigit, "_napps: "
		    "End of current block ", (ftnlen)29);
	}

/*        %------------------------------------------------% */
/*        | No reason to apply a shift to block of order 1 | */
/*        | or if the current block starts after the point | */
/*        | of compression since we'll discard this stuff  | */
/*        %------------------------------------------------% */

	if (istart == iend || istart > *kev) {
	    goto L100;
	}

	i__2 = istart + istart * h_dim1;
	h11.r = h__[i__2].r, h11.i = h__[i__2].i;
	i__2 = istart + 1 + istart * h_dim1;
	h21.r = h__[i__2].r, h21.i = h__[i__2].i;
	q__1.r = h11.r - sigma.r, q__1.i = h11.i - sigma.i;
	f.r = q__1.r, f.i = q__1.i;
	g.r = h21.r, g.i = h21.i;

	i__2 = iend - 1;
	for (i__ = istart; i__ <= i__2; ++i__) {

/*           %------------------------------------------------------% */
/*           | Construct the plane rotation G to zero out the bulge | */
/*           %------------------------------------------------------% */

	    clartg_(&f, &g, &c__, &s, &r__);
	    if (i__ > istart) {
		i__3 = i__ + (i__ - 1) * h_dim1;
		h__[i__3].r = r__.r, h__[i__3].i = r__.i;
		i__3 = i__ + 1 + (i__ - 1) * h_dim1;
		h__[i__3].r = 0.f, h__[i__3].i = 0.f;
	    }

/*           %---------------------------------------------% */
/*           | Apply rotation to the left of H;  H <- G'*H | */
/*           %---------------------------------------------% */

	    i__3 = kplusp;
	    for (j = i__; j <= i__3; ++j) {
		i__4 = i__ + j * h_dim1;
		q__2.r = c__ * h__[i__4].r, q__2.i = c__ * h__[i__4].i;
		i__5 = i__ + 1 + j * h_dim1;
		q__3.r = s.r * h__[i__5].r - s.i * h__[i__5].i, q__3.i = s.r *
			 h__[i__5].i + s.i * h__[i__5].r;
		q__1.r = q__2.r + q__3.r, q__1.i = q__2.i + q__3.i;
		t.r = q__1.r, t.i = q__1.i;
		i__4 = i__ + 1 + j * h_dim1;
		r_cnjg(&q__4, &s);
		q__3.r = -q__4.r, q__3.i = -q__4.i;
		i__5 = i__ + j * h_dim1;
		q__2.r = q__3.r * h__[i__5].r - q__3.i * h__[i__5].i, q__2.i =
			 q__3.r * h__[i__5].i + q__3.i * h__[i__5].r;
		i__6 = i__ + 1 + j * h_dim1;
		q__5.r = c__ * h__[i__6].r, q__5.i = c__ * h__[i__6].i;
		q__1.r = q__2.r + q__5.r, q__1.i = q__2.i + q__5.i;
		h__[i__4].r = q__1.r, h__[i__4].i = q__1.i;
		i__4 = i__ + j * h_dim1;
		h__[i__4].r = t.r, h__[i__4].i = t.i;
/* L50: */
	    }

/*           %---------------------------------------------% */
/*           | Apply rotation to the right of H;  H <- H*G | */
/*           %---------------------------------------------% */

/* Computing MIN */
	    i__4 = i__ + 2;
	    i__3 = min(i__4,iend);
	    for (j = 1; j <= i__3; ++j) {
		i__4 = j + i__ * h_dim1;
		q__2.r = c__ * h__[i__4].r, q__2.i = c__ * h__[i__4].i;
		r_cnjg(&q__4, &s);
		i__5 = j + (i__ + 1) * h_dim1;
		q__3.r = q__4.r * h__[i__5].r - q__4.i * h__[i__5].i, q__3.i =
			 q__4.r * h__[i__5].i + q__4.i * h__[i__5].r;
		q__1.r = q__2.r + q__3.r, q__1.i = q__2.i + q__3.i;
		t.r = q__1.r, t.i = q__1.i;
		i__4 = j + (i__ + 1) * h_dim1;
		q__3.r = -s.r, q__3.i = -s.i;
		i__5 = j + i__ * h_dim1;
		q__2.r = q__3.r * h__[i__5].r - q__3.i * h__[i__5].i, q__2.i =
			 q__3.r * h__[i__5].i + q__3.i * h__[i__5].r;
		i__6 = j + (i__ + 1) * h_dim1;
		q__4.r = c__ * h__[i__6].r, q__4.i = c__ * h__[i__6].i;
		q__1.r = q__2.r + q__4.r, q__1.i = q__2.i + q__4.i;
		h__[i__4].r = q__1.r, h__[i__4].i = q__1.i;
		i__4 = j + i__ * h_dim1;
		h__[i__4].r = t.r, h__[i__4].i = t.i;
/* L60: */
	    }

/*           %-----------------------------------------------------% */
/*           | Accumulate the rotation in the matrix Q;  Q <- Q*G' | */
/*           %-----------------------------------------------------% */

/* Computing MIN */
	    i__4 = i__ + jj;
	    i__3 = min(i__4,kplusp);
	    for (j = 1; j <= i__3; ++j) {
		i__4 = j + i__ * q_dim1;
		q__2.r = c__ * q[i__4].r, q__2.i = c__ * q[i__4].i;
		r_cnjg(&q__4, &s);
		i__5 = j + (i__ + 1) * q_dim1;
		q__3.r = q__4.r * q[i__5].r - q__4.i * q[i__5].i, q__3.i = 
			q__4.r * q[i__5].i + q__4.i * q[i__5].r;
		q__1.r = q__2.r + q__3.r, q__1.i = q__2.i + q__3.i;
		t.r = q__1.r, t.i = q__1.i;
		i__4 = j + (i__ + 1) * q_dim1;
		q__3.r = -s.r, q__3.i = -s.i;
		i__5 = j + i__ * q_dim1;
		q__2.r = q__3.r * q[i__5].r - q__3.i * q[i__5].i, q__2.i = 
			q__3.r * q[i__5].i + q__3.i * q[i__5].r;
		i__6 = j + (i__ + 1) * q_dim1;
		q__4.r = c__ * q[i__6].r, q__4.i = c__ * q[i__6].i;
		q__1.r = q__2.r + q__4.r, q__1.i = q__2.i + q__4.i;
		q[i__4].r = q__1.r, q[i__4].i = q__1.i;
		i__4 = j + i__ * q_dim1;
		q[i__4].r = t.r, q[i__4].i = t.i;
/* L70: */
	    }

/*           %---------------------------% */
/*           | Prepare for next rotation | */
/*           %---------------------------% */

	    if (i__ < iend - 1) {
		i__3 = i__ + 1 + i__ * h_dim1;
		f.r = h__[i__3].r, f.i = h__[i__3].i;
		i__3 = i__ + 2 + i__ * h_dim1;
		g.r = h__[i__3].r, g.i = h__[i__3].i;
	    }
/* L80: */
	}

/*        %-------------------------------% */
/*        | Finished applying the shift.  | */
/*        %-------------------------------% */

L100:

/*        %---------------------------------------------------------% */
/*        | Apply the same shift to the next block if there is any. | */
/*        %---------------------------------------------------------% */

	istart = iend + 1;
	if (iend < kplusp) {
	    goto L20;
	}

/*        %---------------------------------------------% */
/*        | Loop back to the top to get the next shift. | */
/*        %---------------------------------------------% */

/* L110: */
    }

/*     %---------------------------------------------------% */
/*     | Perform a similarity transformation that makes    | */
/*     | sure that the compressed H will have non-negative | */
/*     | real subdiagonal elements.                        | */
/*     %---------------------------------------------------% */

    i__1 = *kev;
    for (j = 1; j <= i__1; ++j) {
	i__2 = j + 1 + j * h_dim1;
	if (h__[i__2].r < 0.f || r_imag(&h__[j + 1 + j * h_dim1]) != 0.f) {
	    i__2 = j + 1 + j * h_dim1;
	    i__3 = j + 1 + j * h_dim1;
	    r__2 = h__[i__3].r;
	    r__3 = r_imag(&h__[j + 1 + j * h_dim1]);
	    r__1 = slapy2_(&r__2, &r__3);
	    q__1.r = h__[i__2].r / r__1, q__1.i = h__[i__2].i / r__1;
	    t.r = q__1.r, t.i = q__1.i;
	    i__2 = kplusp - j + 1;
	    r_cnjg(&q__1, &t);
	    cscal_(&i__2, &q__1, &h__[j + 1 + j * h_dim1], ldh);
/* Computing MIN */
	    i__3 = j + 2;
	    i__2 = min(i__3,kplusp);
	    cscal_(&i__2, &t, &h__[(j + 1) * h_dim1 + 1], &c__1);
/* Computing MIN */
	    i__3 = j + *np + 1;
	    i__2 = min(i__3,kplusp);
	    cscal_(&i__2, &t, &q[(j + 1) * q_dim1 + 1], &c__1);
	    i__2 = j + 1 + j * h_dim1;
	    i__3 = j + 1 + j * h_dim1;
	    r__1 = h__[i__3].r;
	    q__1.r = r__1, q__1.i = 0.f;
	    h__[i__2].r = q__1.r, h__[i__2].i = q__1.i;
	}
/* L120: */
    }

    i__1 = *kev;
    for (i__ = 1; i__ <= i__1; ++i__) {

/*        %--------------------------------------------% */
/*        | Final check for splitting and deflation.   | */
/*        | Use a standard test as in the QR algorithm | */
/*        | REFERENCE: LAPACK subroutine clahqr.       | */
/*        | Note: Since the subdiagonals of the        | */
/*        | compressed H are nonnegative real numbers, | */
/*        | we take advantage of this.                 | */
/*        %--------------------------------------------% */

	i__2 = i__ + i__ * h_dim1;
	i__3 = i__ + 1 + (i__ + 1) * h_dim1;
	tst1 = (r__1 = h__[i__2].r, dabs(r__1)) + (r__2 = r_imag(&h__[i__ + 
		i__ * h_dim1]), dabs(r__2)) + ((r__3 = h__[i__3].r, dabs(r__3)
		) + (r__4 = r_imag(&h__[i__ + 1 + (i__ + 1) * h_dim1]), dabs(
		r__4)));
	if (tst1 == 0.f) {
	    tst1 = clanhs_("1", kev, &h__[h_offset], ldh, &workl[1], (ftnlen)
		    1);
	}
	i__2 = i__ + 1 + i__ * h_dim1;
/* Computing MAX */
	r__1 = ulp * tst1;
	if (h__[i__2].r <= dmax(r__1,smlnum)) {
	    i__3 = i__ + 1 + i__ * h_dim1;
	    h__[i__3].r = 0.f, h__[i__3].i = 0.f;
	}
/* L130: */
    }

/*     %-------------------------------------------------% */
/*     | Compute the (kev+1)-st column of (V*Q) and      | */
/*     | temporarily store the result in WORKD(N+1:2*N). | */
/*     | This is needed in the residual update since we  | */
/*     | cannot GUARANTEE that the corresponding entry   | */
/*     | of H would be zero as in exact arithmetic.      | */
/*     %-------------------------------------------------% */

    i__1 = *kev + 1 + *kev * h_dim1;
    if (h__[i__1].r > 0.f) {
	cgemv_("N", n, &kplusp, &c_b1, &v[v_offset], ldv, &q[(*kev + 1) * 
		q_dim1 + 1], &c__1, &c_b2, &workd[*n + 1], &c__1, (ftnlen)1);
    }

/*     %----------------------------------------------------------% */
/*     | Compute column 1 to kev of (V*Q) in backward order       | */
/*     | taking advantage of the upper Hessenberg structure of Q. | */
/*     %----------------------------------------------------------% */

    i__1 = *kev;
    for (i__ = 1; i__ <= i__1; ++i__) {
	i__2 = kplusp - i__ + 1;
	cgemv_("N", n, &i__2, &c_b1, &v[v_offset], ldv, &q[(*kev - i__ + 1) * 
		q_dim1 + 1], &c__1, &c_b2, &workd[1], &c__1, (ftnlen)1);
	ccopy_(n, &workd[1], &c__1, &v[(kplusp - i__ + 1) * v_dim1 + 1], &
		c__1);
/* L140: */
    }

/*     %-------------------------------------------------% */
/*     |  Move v(:,kplusp-kev+1:kplusp) into v(:,1:kev). | */
/*     %-------------------------------------------------% */

    clacpy_("A", n, kev, &v[(kplusp - *kev + 1) * v_dim1 + 1], ldv, &v[
	    v_offset], ldv, (ftnlen)1);

/*     %--------------------------------------------------------------% */
/*     | Copy the (kev+1)-st column of (V*Q) in the appropriate place | */
/*     %--------------------------------------------------------------% */

    i__1 = *kev + 1 + *kev * h_dim1;
    if (h__[i__1].r > 0.f) {
	ccopy_(n, &workd[*n + 1], &c__1, &v[(*kev + 1) * v_dim1 + 1], &c__1);
    }

/*     %-------------------------------------% */
/*     | Update the residual vector:         | */
/*     |    r <- sigmak*r + betak*v(:,kev+1) | */
/*     | where                               | */
/*     |    sigmak = (e_{kev+p}'*Q)*e_{kev}  | */
/*     |    betak = e_{kev+1}'*H*e_{kev}     | */
/*     %-------------------------------------% */

    cscal_(n, &q[kplusp + *kev * q_dim1], &resid[1], &c__1);
    i__1 = *kev + 1 + *kev * h_dim1;
    if (h__[i__1].r > 0.f) {
	caxpy_(n, &h__[*kev + 1 + *kev * h_dim1], &v[(*kev + 1) * v_dim1 + 1],
		 &c__1, &resid[1], &c__1);
    }

    if (msglvl > 1) {
	cvout_(&debug_1.logfil, &c__1, &q[kplusp + *kev * q_dim1], &
		debug_1.ndigit, "_napps: sigmak = (e_{kev+p}^T*Q)*e_{kev}", (
		ftnlen)40);
	cvout_(&debug_1.logfil, &c__1, &h__[*kev + 1 + *kev * h_dim1], &
		debug_1.ndigit, "_napps: betak = e_{kev+1}^T*H*e_{kev}", (
		ftnlen)37);
	ivout_(&debug_1.logfil, &c__1, kev, &debug_1.ndigit, "_napps: Order "
		"of the final Hessenberg matrix ", (ftnlen)45);
	if (msglvl > 2) {
	    cmout_(&debug_1.logfil, kev, kev, &h__[h_offset], ldh, &
		    debug_1.ndigit, "_napps: updated Hessenberg matrix H for"
		    " next iteration", (ftnlen)54);
	}

    }

L9000:
    second_(&t1);
    timing_1.tcapps += t1 - t0;

    return 0;

/*     %---------------% */
/*     | End of cnapps | */
/*     %---------------% */

} /* cnapps_ */