/* -- translated by f2c (version 19940927).
You must link the resulting object file with the libraries:
-lf2c -lm (in that order)
*/
#include "f2c.h"
/* Table of constant values */
static complex c_b1 = {0.f,0.f};
static complex c_b2 = {1.f,0.f};
static integer c__3 = 3;
static integer c__1 = 1;
/* Subroutine */ int clarge_(integer *n, complex *a, integer *lda, integer *
iseed, complex *work, integer *info)
{
/* System generated locals */
integer a_dim1, a_offset, i__1;
doublereal d__1;
complex q__1;
/* Builtin functions */
double c_abs(complex *);
void c_div(complex *, complex *, complex *);
/* Local variables */
static integer i;
extern /* Subroutine */ int cgerc_(integer *, integer *, complex *,
complex *, integer *, complex *, integer *, complex *, integer *),
cscal_(integer *, complex *, complex *, integer *), cgemv_(char *
, integer *, integer *, complex *, complex *, integer *, complex *
, integer *, complex *, complex *, integer *);
extern real scnrm2_(integer *, complex *, integer *);
static complex wa, wb;
static real wn;
extern /* Subroutine */ int xerbla_(char *, integer *), clarnv_(
integer *, integer *, integer *, complex *);
static complex tau;
/* -- LAPACK auxiliary test routine (version 2.0) --
Univ. of Tennessee, Univ. of California Berkeley, NAG Ltd.,
Courant Institute, Argonne National Lab, and Rice University
September 30, 1994
Purpose
=======
CLARGE pre- and post-multiplies a complex general n by n matrix A
with a random unitary matrix: A = U*D*U'.
Arguments
=========
N (input) INTEGER
The order of the matrix A. N >= 0.
A (input/output) COMPLEX array, dimension (LDA,N)
On entry, the original n by n matrix A.
On exit, A is overwritten by U*A*U' for some random
unitary matrix U.
LDA (input) INTEGER
The leading dimension of the array A. LDA >= N.
ISEED (input/output) INTEGER array, dimension (4)
On entry, the seed of the random number generator; the array
elements must be between 0 and 4095, and ISEED(4) must be
odd.
On exit, the seed is updated.
WORK (workspace) COMPLEX array, dimension (2*N)
INFO (output) INTEGER
= 0: successful exit
< 0: if INFO = -i, the i-th argument had an illegal value
=====================================================================
Test the input arguments
Parameter adjustments */
a_dim1 = *lda;
a_offset = a_dim1 + 1;
a -= a_offset;
--iseed;
--work;
/* Function Body */
*info = 0;
if (*n < 0) {
*info = -1;
} else if (*lda < max(1,*n)) {
*info = -3;
}
if (*info < 0) {
i__1 = -(*info);
xerbla_("CLARGE", &i__1);
return 0;
}
/* pre- and post-multiply A by random unitary matrix */
for (i = *n; i >= 1; --i) {
/* generate random reflection */
i__1 = *n - i + 1;
clarnv_(&c__3, &iseed[1], &i__1, &work[1]);
i__1 = *n - i + 1;
wn = scnrm2_(&i__1, &work[1], &c__1);
d__1 = wn / c_abs(&work[1]);
q__1.r = d__1 * work[1].r, q__1.i = d__1 * work[1].i;
wa.r = q__1.r, wa.i = q__1.i;
if (wn == 0.f) {
tau.r = 0.f, tau.i = 0.f;
} else {
q__1.r = work[1].r + wa.r, q__1.i = work[1].i + wa.i;
wb.r = q__1.r, wb.i = q__1.i;
i__1 = *n - i;
c_div(&q__1, &c_b2, &wb);
cscal_(&i__1, &q__1, &work[2], &c__1);
work[1].r = 1.f, work[1].i = 0.f;
c_div(&q__1, &wb, &wa);
d__1 = q__1.r;
tau.r = d__1, tau.i = 0.f;
}
/* multiply A(i:n,1:n) by random reflection from the left */
i__1 = *n - i + 1;
cgemv_("Conjugate transpose", &i__1, n, &c_b2, &a[i + a_dim1], lda, &
work[1], &c__1, &c_b1, &work[*n + 1], &c__1);
i__1 = *n - i + 1;
q__1.r = -(doublereal)tau.r, q__1.i = -(doublereal)tau.i;
cgerc_(&i__1, n, &q__1, &work[1], &c__1, &work[*n + 1], &c__1, &a[i +
a_dim1], lda);
/* multiply A(1:n,i:n) by random reflection from the right */
i__1 = *n - i + 1;
cgemv_("No transpose", n, &i__1, &c_b2, &a[i * a_dim1 + 1], lda, &
work[1], &c__1, &c_b1, &work[*n + 1], &c__1);
i__1 = *n - i + 1;
q__1.r = -(doublereal)tau.r, q__1.i = -(doublereal)tau.i;
cgerc_(n, &i__1, &q__1, &work[*n + 1], &c__1, &work[1], &c__1, &a[i *
a_dim1 + 1], lda);
/* L10: */
}
return 0;
/* End of CLARGE */
} /* clarge_ */