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/* cunghr.f -- translated by f2c (version 20061008).
You must link the resulting object file with libf2c:
on Microsoft Windows system, link with libf2c.lib;
on Linux or Unix systems, link with .../path/to/libf2c.a -lm
or, if you install libf2c.a in a standard place, with -lf2c -lm
-- in that order, at the end of the command line, as in
cc *.o -lf2c -lm
Source for libf2c is in /netlib/f2c/libf2c.zip, e.g.,
http://www.netlib.org/f2c/libf2c.zip
*/
#include "f2c.h"
#include "blaswrap.h"
/* Table of constant values */
static integer c__1 = 1;
static integer c_n1 = -1;
/* Subroutine */ int cunghr_(integer *n, integer *ilo, integer *ihi, complex *
a, integer *lda, complex *tau, complex *work, integer *lwork, integer
*info)
{
/* System generated locals */
integer a_dim1, a_offset, i__1, i__2, i__3, i__4;
/* Local variables */
integer i__, j, nb, nh, iinfo;
extern /* Subroutine */ int xerbla_(char *, integer *);
extern integer ilaenv_(integer *, char *, char *, integer *, integer *,
integer *, integer *);
extern /* Subroutine */ int cungqr_(integer *, integer *, integer *,
complex *, integer *, complex *, complex *, integer *, integer *);
integer lwkopt;
logical lquery;
/* -- LAPACK routine (version 3.2) -- */
/* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */
/* November 2006 */
/* .. Scalar Arguments .. */
/* .. */
/* .. Array Arguments .. */
/* .. */
/* Purpose */
/* ======= */
/* CUNGHR generates a complex unitary matrix Q which is defined as the */
/* product of IHI-ILO elementary reflectors of order N, as returned by */
/* CGEHRD: */
/* Q = H(ilo) H(ilo+1) . . . H(ihi-1). */
/* Arguments */
/* ========= */
/* N (input) INTEGER */
/* The order of the matrix Q. N >= 0. */
/* ILO (input) INTEGER */
/* IHI (input) INTEGER */
/* ILO and IHI must have the same values as in the previous call */
/* of CGEHRD. Q is equal to the unit matrix except in the */
/* submatrix Q(ilo+1:ihi,ilo+1:ihi). */
/* 1 <= ILO <= IHI <= N, if N > 0; ILO=1 and IHI=0, if N=0. */
/* A (input/output) COMPLEX array, dimension (LDA,N) */
/* On entry, the vectors which define the elementary reflectors, */
/* as returned by CGEHRD. */
/* On exit, the N-by-N unitary matrix Q. */
/* LDA (input) INTEGER */
/* The leading dimension of the array A. LDA >= max(1,N). */
/* TAU (input) COMPLEX array, dimension (N-1) */
/* TAU(i) must contain the scalar factor of the elementary */
/* reflector H(i), as returned by CGEHRD. */
/* 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 >= IHI-ILO. */
/* For optimum performance LWORK >= (IHI-ILO)*NB, where NB is */
/* the optimal blocksize. */
/* 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 */
/* ===================================================================== */
/* .. Parameters .. */
/* .. */
/* .. Local Scalars .. */
/* .. */
/* .. External Subroutines .. */
/* .. */
/* .. External Functions .. */
/* .. */
/* .. Intrinsic Functions .. */
/* .. */
/* .. Executable Statements .. */
/* Test the input arguments */
/* Parameter adjustments */
a_dim1 = *lda;
a_offset = 1 + a_dim1;
a -= a_offset;
--tau;
--work;
/* Function Body */
*info = 0;
nh = *ihi - *ilo;
lquery = *lwork == -1;
if (*n < 0) {
*info = -1;
} else if (*ilo < 1 || *ilo > max(1,*n)) {
*info = -2;
} else if (*ihi < min(*ilo,*n) || *ihi > *n) {
*info = -3;
} else if (*lda < max(1,*n)) {
*info = -5;
} else if (*lwork < max(1,nh) && ! lquery) {
*info = -8;
}
if (*info == 0) {
nb = ilaenv_(&c__1, "CUNGQR", " ", &nh, &nh, &nh, &c_n1);
lwkopt = max(1,nh) * nb;
work[1].r = (real) lwkopt, work[1].i = 0.f;
}
if (*info != 0) {
i__1 = -(*info);
xerbla_("CUNGHR", &i__1);
return 0;
} else if (lquery) {
return 0;
}
/* Quick return if possible */
if (*n == 0) {
work[1].r = 1.f, work[1].i = 0.f;
return 0;
}
/* Shift the vectors which define the elementary reflectors one */
/* column to the right, and set the first ilo and the last n-ihi */
/* rows and columns to those of the unit matrix */
i__1 = *ilo + 1;
for (j = *ihi; j >= i__1; --j) {
i__2 = j - 1;
for (i__ = 1; i__ <= i__2; ++i__) {
i__3 = i__ + j * a_dim1;
a[i__3].r = 0.f, a[i__3].i = 0.f;
/* L10: */
}
i__2 = *ihi;
for (i__ = j + 1; i__ <= i__2; ++i__) {
i__3 = i__ + j * a_dim1;
i__4 = i__ + (j - 1) * a_dim1;
a[i__3].r = a[i__4].r, a[i__3].i = a[i__4].i;
/* L20: */
}
i__2 = *n;
for (i__ = *ihi + 1; i__ <= i__2; ++i__) {
i__3 = i__ + j * a_dim1;
a[i__3].r = 0.f, a[i__3].i = 0.f;
/* L30: */
}
/* L40: */
}
i__1 = *ilo;
for (j = 1; j <= i__1; ++j) {
i__2 = *n;
for (i__ = 1; i__ <= i__2; ++i__) {
i__3 = i__ + j * a_dim1;
a[i__3].r = 0.f, a[i__3].i = 0.f;
/* L50: */
}
i__2 = j + j * a_dim1;
a[i__2].r = 1.f, a[i__2].i = 0.f;
/* L60: */
}
i__1 = *n;
for (j = *ihi + 1; j <= i__1; ++j) {
i__2 = *n;
for (i__ = 1; i__ <= i__2; ++i__) {
i__3 = i__ + j * a_dim1;
a[i__3].r = 0.f, a[i__3].i = 0.f;
/* L70: */
}
i__2 = j + j * a_dim1;
a[i__2].r = 1.f, a[i__2].i = 0.f;
/* L80: */
}
if (nh > 0) {
/* Generate Q(ilo+1:ihi,ilo+1:ihi) */
cungqr_(&nh, &nh, &nh, &a[*ilo + 1 + (*ilo + 1) * a_dim1], lda, &tau[*
ilo], &work[1], lwork, &iinfo);
}
work[1].r = (real) lwkopt, work[1].i = 0.f;
return 0;
/* End of CUNGHR */
} /* cunghr_ */
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