/* clarz.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 complex c_b1 = {1.f,0.f};
static integer c__1 = 1;
/* Subroutine */ int clarz_(char *side, integer *m, integer *n, integer *l,
complex *v, integer *incv, complex *tau, complex *c__, integer *ldc,
complex *work)
{
/* System generated locals */
integer c_dim1, c_offset;
complex q__1;
/* Local variables */
extern /* Subroutine */ int cgerc_(integer *, integer *, complex *,
complex *, integer *, complex *, integer *, complex *, integer *),
cgemv_(char *, integer *, integer *, complex *, complex *,
integer *, complex *, integer *, complex *, complex *, integer *);
extern logical lsame_(char *, char *);
extern /* Subroutine */ int cgeru_(integer *, integer *, complex *,
complex *, integer *, complex *, integer *, complex *, integer *),
ccopy_(integer *, complex *, integer *, complex *, integer *),
caxpy_(integer *, complex *, complex *, integer *, complex *,
integer *), clacgv_(integer *, complex *, integer *);
/* -- LAPACK routine (version 3.2) -- */
/* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */
/* November 2006 */
/* .. Scalar Arguments .. */
/* .. */
/* .. Array Arguments .. */
/* .. */
/* Purpose */
/* ======= */
/* CLARZ applies a complex elementary reflector H to a complex */
/* M-by-N matrix C, from either the left or the right. H is represented */
/* in the form */
/* H = I - tau * v * v' */
/* where tau is a complex scalar and v is a complex vector. */
/* If tau = 0, then H is taken to be the unit matrix. */
/* To apply H' (the conjugate transpose of H), supply conjg(tau) instead */
/* tau. */
/* H is a product of k elementary reflectors as returned by CTZRZF. */
/* Arguments */
/* ========= */
/* SIDE (input) CHARACTER*1 */
/* = 'L': form H * C */
/* = 'R': form C * H */
/* M (input) INTEGER */
/* The number of rows of the matrix C. */
/* N (input) INTEGER */
/* The number of columns of the matrix C. */
/* L (input) INTEGER */
/* The number of entries of the vector V containing */
/* the meaningful part of the Householder vectors. */
/* If SIDE = 'L', M >= L >= 0, if SIDE = 'R', N >= L >= 0. */
/* V (input) COMPLEX array, dimension (1+(L-1)*abs(INCV)) */
/* The vector v in the representation of H as returned by */
/* CTZRZF. V is not used if TAU = 0. */
/* INCV (input) INTEGER */
/* The increment between elements of v. INCV <> 0. */
/* TAU (input) COMPLEX */
/* The value tau in the representation of H. */
/* C (input/output) COMPLEX array, dimension (LDC,N) */
/* On entry, the M-by-N matrix C. */
/* On exit, C is overwritten by the matrix H * C if SIDE = 'L', */
/* or C * H if SIDE = 'R'. */
/* LDC (input) INTEGER */
/* The leading dimension of the array C. LDC >= max(1,M). */
/* WORK (workspace) COMPLEX array, dimension */
/* (N) if SIDE = 'L' */
/* or (M) if SIDE = 'R' */
/* Further Details */
/* =============== */
/* Based on contributions by */
/* A. Petitet, Computer Science Dept., Univ. of Tenn., Knoxville, USA */
/* ===================================================================== */
/* .. Parameters .. */
/* .. */
/* .. External Subroutines .. */
/* .. */
/* .. External Functions .. */
/* .. */
/* .. Executable Statements .. */
/* Parameter adjustments */
--v;
c_dim1 = *ldc;
c_offset = 1 + c_dim1;
c__ -= c_offset;
--work;
/* Function Body */
if (lsame_(side, "L")) {
/* Form H * C */
if (tau->r != 0.f || tau->i != 0.f) {
/* w( 1:n ) = conjg( C( 1, 1:n ) ) */
ccopy_(n, &c__[c_offset], ldc, &work[1], &c__1);
clacgv_(n, &work[1], &c__1);
/* w( 1:n ) = conjg( w( 1:n ) + C( m-l+1:m, 1:n )' * v( 1:l ) ) */
cgemv_("Conjugate transpose", l, n, &c_b1, &c__[*m - *l + 1 +
c_dim1], ldc, &v[1], incv, &c_b1, &work[1], &c__1);
clacgv_(n, &work[1], &c__1);
/* C( 1, 1:n ) = C( 1, 1:n ) - tau * w( 1:n ) */
q__1.r = -tau->r, q__1.i = -tau->i;
caxpy_(n, &q__1, &work[1], &c__1, &c__[c_offset], ldc);
/* C( m-l+1:m, 1:n ) = C( m-l+1:m, 1:n ) - ... */
/* tau * v( 1:l ) * conjg( w( 1:n )' ) */
q__1.r = -tau->r, q__1.i = -tau->i;
cgeru_(l, n, &q__1, &v[1], incv, &work[1], &c__1, &c__[*m - *l +
1 + c_dim1], ldc);
}
} else {
/* Form C * H */
if (tau->r != 0.f || tau->i != 0.f) {
/* w( 1:m ) = C( 1:m, 1 ) */
ccopy_(m, &c__[c_offset], &c__1, &work[1], &c__1);
/* w( 1:m ) = w( 1:m ) + C( 1:m, n-l+1:n, 1:n ) * v( 1:l ) */
cgemv_("No transpose", m, l, &c_b1, &c__[(*n - *l + 1) * c_dim1 +
1], ldc, &v[1], incv, &c_b1, &work[1], &c__1);
/* C( 1:m, 1 ) = C( 1:m, 1 ) - tau * w( 1:m ) */
q__1.r = -tau->r, q__1.i = -tau->i;
caxpy_(m, &q__1, &work[1], &c__1, &c__[c_offset], &c__1);
/* C( 1:m, n-l+1:n ) = C( 1:m, n-l+1:n ) - ... */
/* tau * w( 1:m ) * v( 1:l )' */
q__1.r = -tau->r, q__1.i = -tau->i;
cgerc_(m, l, &q__1, &work[1], &c__1, &v[1], incv, &c__[(*n - *l +
1) * c_dim1 + 1], ldc);
}
}
return 0;
/* End of CLARZ */
} /* clarz_ */
