161 lines
4.6 KiB
C
161 lines
4.6 KiB
C
/* -- translated by f2c (version 19940927).
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You must link the resulting object file with the libraries:
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-lf2c -lm (in that order)
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*/
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#include "f2c.h"
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/* Table of constant values */
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static doublecomplex c_b1 = {0.,0.};
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static doublecomplex c_b2 = {1.,0.};
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static integer c__3 = 3;
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static integer c__1 = 1;
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/* Subroutine */ int zlarge_(integer *n, doublecomplex *a, integer *lda,
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integer *iseed, doublecomplex *work, integer *info)
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{
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/* System generated locals */
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integer a_dim1, a_offset, i__1;
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doublereal d__1;
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doublecomplex z__1;
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/* Builtin functions */
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double z_abs(doublecomplex *);
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void z_div(doublecomplex *, doublecomplex *, doublecomplex *);
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/* Local variables */
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static integer i;
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extern /* Subroutine */ int zgerc_(integer *, integer *, doublecomplex *,
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doublecomplex *, integer *, doublecomplex *, integer *,
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doublecomplex *, integer *), zscal_(integer *, doublecomplex *,
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doublecomplex *, integer *), zgemv_(char *, integer *, integer *,
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doublecomplex *, doublecomplex *, integer *, doublecomplex *,
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integer *, doublecomplex *, doublecomplex *, integer *);
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extern doublereal dznrm2_(integer *, doublecomplex *, integer *);
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static doublecomplex wa, wb;
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static doublereal wn;
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extern /* Subroutine */ int xerbla_(char *, integer *), zlarnv_(
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integer *, integer *, integer *, doublecomplex *);
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static doublecomplex tau;
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/* -- LAPACK auxiliary test routine (version 2.0) --
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Univ. of Tennessee, Univ. of California Berkeley, NAG Ltd.,
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Courant Institute, Argonne National Lab, and Rice University
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September 30, 1994
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Purpose
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=======
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ZLARGE pre- and post-multiplies a complex general n by n matrix A
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with a random unitary matrix: A = U*D*U'.
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Arguments
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=========
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N (input) INTEGER
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The order of the matrix A. N >= 0.
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A (input/output) COMPLEX*16 array, dimension (LDA,N)
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On entry, the original n by n matrix A.
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On exit, A is overwritten by U*A*U' for some random
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unitary matrix U.
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LDA (input) INTEGER
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The leading dimension of the array A. LDA >= N.
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ISEED (input/output) INTEGER array, dimension (4)
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On entry, the seed of the random number generator; the array
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elements must be between 0 and 4095, and ISEED(4) must be
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odd.
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On exit, the seed is updated.
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WORK (workspace) COMPLEX*16 array, dimension (2*N)
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INFO (output) INTEGER
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= 0: successful exit
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< 0: if INFO = -i, the i-th argument had an illegal value
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=====================================================================
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Test the input arguments
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Parameter adjustments */
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a_dim1 = *lda;
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a_offset = a_dim1 + 1;
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a -= a_offset;
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--iseed;
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--work;
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/* Function Body */
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*info = 0;
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if (*n < 0) {
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*info = -1;
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} else if (*lda < max(1,*n)) {
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*info = -3;
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}
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if (*info < 0) {
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i__1 = -(*info);
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xerbla_("ZLARGE", &i__1);
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return 0;
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}
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/* pre- and post-multiply A by random unitary matrix */
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for (i = *n; i >= 1; --i) {
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/* generate random reflection */
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i__1 = *n - i + 1;
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zlarnv_(&c__3, &iseed[1], &i__1, &work[1]);
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i__1 = *n - i + 1;
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wn = dznrm2_(&i__1, &work[1], &c__1);
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d__1 = wn / z_abs(&work[1]);
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z__1.r = d__1 * work[1].r, z__1.i = d__1 * work[1].i;
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wa.r = z__1.r, wa.i = z__1.i;
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if (wn == 0.) {
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tau.r = 0., tau.i = 0.;
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} else {
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z__1.r = work[1].r + wa.r, z__1.i = work[1].i + wa.i;
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wb.r = z__1.r, wb.i = z__1.i;
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i__1 = *n - i;
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z_div(&z__1, &c_b2, &wb);
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zscal_(&i__1, &z__1, &work[2], &c__1);
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work[1].r = 1., work[1].i = 0.;
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z_div(&z__1, &wb, &wa);
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d__1 = z__1.r;
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tau.r = d__1, tau.i = 0.;
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}
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/* multiply A(i:n,1:n) by random reflection from the left */
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i__1 = *n - i + 1;
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zgemv_("Conjugate transpose", &i__1, n, &c_b2, &a[i + a_dim1], lda, &
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work[1], &c__1, &c_b1, &work[*n + 1], &c__1);
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i__1 = *n - i + 1;
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z__1.r = -tau.r, z__1.i = -tau.i;
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zgerc_(&i__1, n, &z__1, &work[1], &c__1, &work[*n + 1], &c__1, &a[i +
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a_dim1], lda);
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/* multiply A(1:n,i:n) by random reflection from the right */
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i__1 = *n - i + 1;
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zgemv_("No transpose", n, &i__1, &c_b2, &a[i * a_dim1 + 1], lda, &
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work[1], &c__1, &c_b1, &work[*n + 1], &c__1);
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i__1 = *n - i + 1;
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z__1.r = -tau.r, z__1.i = -tau.i;
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zgerc_(n, &i__1, &z__1, &work[*n + 1], &c__1, &work[1], &c__1, &a[i *
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a_dim1 + 1], lda);
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/* L10: */
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}
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return 0;
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/* End of ZLARGE */
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} /* zlarge_ */
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