#include "blaswrap.h"
#include "f2c.h"
/* Subroutine */ int clarzb_(char *side, char *trans, char *direct, char *
storev, integer *m, integer *n, integer *k, integer *l, complex *v,
integer *ldv, complex *t, integer *ldt, complex *c__, integer *ldc,
complex *work, integer *ldwork)
{
/* -- LAPACK routine (version 3.1) --
Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd..
November 2006
Purpose
=======
CLARZB applies a complex block reflector H or its transpose H**H
to a complex distributed M-by-N C from the left or the right.
Currently, only STOREV = 'R' and DIRECT = 'B' are supported.
Arguments
=========
SIDE (input) CHARACTER*1
= 'L': apply H or H' from the Left
= 'R': apply H or H' from the Right
TRANS (input) CHARACTER*1
= 'N': apply H (No transpose)
= 'C': apply H' (Conjugate transpose)
DIRECT (input) CHARACTER*1
Indicates how H is formed from a product of elementary
reflectors
= 'F': H = H(1) H(2) . . . H(k) (Forward, not supported yet)
= 'B': H = H(k) . . . H(2) H(1) (Backward)
STOREV (input) CHARACTER*1
Indicates how the vectors which define the elementary
reflectors are stored:
= 'C': Columnwise (not supported yet)
= 'R': Rowwise
M (input) INTEGER
The number of rows of the matrix C.
N (input) INTEGER
The number of columns of the matrix C.
K (input) INTEGER
The order of the matrix T (= the number of elementary
reflectors whose product defines the block reflector).
L (input) INTEGER
The number of columns of the matrix V containing the
meaningful part of the Householder reflectors.
If SIDE = 'L', M >= L >= 0, if SIDE = 'R', N >= L >= 0.
V (input) COMPLEX array, dimension (LDV,NV).
If STOREV = 'C', NV = K; if STOREV = 'R', NV = L.
LDV (input) INTEGER
The leading dimension of the array V.
If STOREV = 'C', LDV >= L; if STOREV = 'R', LDV >= K.
T (input) COMPLEX array, dimension (LDT,K)
The triangular K-by-K matrix T in the representation of the
block reflector.
LDT (input) INTEGER
The leading dimension of the array T. LDT >= K.
C (input/output) COMPLEX array, dimension (LDC,N)
On entry, the M-by-N matrix C.
On exit, C is overwritten by H*C or H'*C or C*H or C*H'.
LDC (input) INTEGER
The leading dimension of the array C. LDC >= max(1,M).
WORK (workspace) COMPLEX array, dimension (LDWORK,K)
LDWORK (input) INTEGER
The leading dimension of the array WORK.
If SIDE = 'L', LDWORK >= max(1,N);
if SIDE = 'R', LDWORK >= max(1,M).
Further Details
===============
Based on contributions by
A. Petitet, Computer Science Dept., Univ. of Tenn., Knoxville, USA
=====================================================================
Quick return if possible
Parameter adjustments */
/* Table of constant values */
static complex c_b1 = {1.f,0.f};
static integer c__1 = 1;
/* System generated locals */
integer c_dim1, c_offset, t_dim1, t_offset, v_dim1, v_offset, work_dim1,
work_offset, i__1, i__2, i__3, i__4, i__5;
complex q__1;
/* Local variables */
static integer i__, j, info;
extern /* Subroutine */ int cgemm_(char *, char *, integer *, integer *,
integer *, complex *, complex *, integer *, complex *, integer *,
complex *, complex *, integer *);
extern logical lsame_(char *, char *);
extern /* Subroutine */ int ccopy_(integer *, complex *, integer *,
complex *, integer *), ctrmm_(char *, char *, char *, char *,
integer *, integer *, complex *, complex *, integer *, complex *,
integer *), clacgv_(integer *,
complex *, integer *), xerbla_(char *, integer *);
static char transt[1];
v_dim1 = *ldv;
v_offset = 1 + v_dim1;
v -= v_offset;
t_dim1 = *ldt;
t_offset = 1 + t_dim1;
t -= t_offset;
c_dim1 = *ldc;
c_offset = 1 + c_dim1;
c__ -= c_offset;
work_dim1 = *ldwork;
work_offset = 1 + work_dim1;
work -= work_offset;
/* Function Body */
if (*m <= 0 || *n <= 0) {
return 0;
}
/* Check for currently supported options */
info = 0;
if (! lsame_(direct, "B")) {
info = -3;
} else if (! lsame_(storev, "R")) {
info = -4;
}
if (info != 0) {
i__1 = -info;
xerbla_("CLARZB", &i__1);
return 0;
}
if (lsame_(trans, "N")) {
*(unsigned char *)transt = 'C';
} else {
*(unsigned char *)transt = 'N';
}
if (lsame_(side, "L")) {
/* Form H * C or H' * C
W( 1:n, 1:k ) = conjg( C( 1:k, 1:n )' ) */
i__1 = *k;
for (j = 1; j <= i__1; ++j) {
ccopy_(n, &c__[j + c_dim1], ldc, &work[j * work_dim1 + 1], &c__1);
/* L10: */
}
/* W( 1:n, 1:k ) = W( 1:n, 1:k ) + ...
conjg( C( m-l+1:m, 1:n )' ) * V( 1:k, 1:l )' */
if (*l > 0) {
cgemm_("Transpose", "Conjugate transpose", n, k, l, &c_b1, &c__[*
m - *l + 1 + c_dim1], ldc, &v[v_offset], ldv, &c_b1, &
work[work_offset], ldwork);
}
/* W( 1:n, 1:k ) = W( 1:n, 1:k ) * T' or W( 1:m, 1:k ) * T */
ctrmm_("Right", "Lower", transt, "Non-unit", n, k, &c_b1, &t[t_offset]
, ldt, &work[work_offset], ldwork);
/* C( 1:k, 1:n ) = C( 1:k, 1:n ) - conjg( W( 1:n, 1:k )' ) */
i__1 = *n;
for (j = 1; j <= i__1; ++j) {
i__2 = *k;
for (i__ = 1; i__ <= i__2; ++i__) {
i__3 = i__ + j * c_dim1;
i__4 = i__ + j * c_dim1;
i__5 = j + i__ * work_dim1;
q__1.r = c__[i__4].r - work[i__5].r, q__1.i = c__[i__4].i -
work[i__5].i;
c__[i__3].r = q__1.r, c__[i__3].i = q__1.i;
/* L20: */
}
/* L30: */
}
/* C( m-l+1:m, 1:n ) = C( m-l+1:m, 1:n ) - ...
conjg( V( 1:k, 1:l )' ) * conjg( W( 1:n, 1:k )' ) */
if (*l > 0) {
q__1.r = -1.f, q__1.i = -0.f;
cgemm_("Transpose", "Transpose", l, n, k, &q__1, &v[v_offset],
ldv, &work[work_offset], ldwork, &c_b1, &c__[*m - *l + 1
+ c_dim1], ldc);
}
} else if (lsame_(side, "R")) {
/* Form C * H or C * H'
W( 1:m, 1:k ) = C( 1:m, 1:k ) */
i__1 = *k;
for (j = 1; j <= i__1; ++j) {
ccopy_(m, &c__[j * c_dim1 + 1], &c__1, &work[j * work_dim1 + 1], &
c__1);
/* L40: */
}
/* W( 1:m, 1:k ) = W( 1:m, 1:k ) + ...
C( 1:m, n-l+1:n ) * conjg( V( 1:k, 1:l )' ) */
if (*l > 0) {
cgemm_("No transpose", "Transpose", m, k, l, &c_b1, &c__[(*n - *l
+ 1) * c_dim1 + 1], ldc, &v[v_offset], ldv, &c_b1, &work[
work_offset], ldwork);
}
/* W( 1:m, 1:k ) = W( 1:m, 1:k ) * conjg( T ) or
W( 1:m, 1:k ) * conjg( T' ) */
i__1 = *k;
for (j = 1; j <= i__1; ++j) {
i__2 = *k - j + 1;
clacgv_(&i__2, &t[j + j * t_dim1], &c__1);
/* L50: */
}
ctrmm_("Right", "Lower", trans, "Non-unit", m, k, &c_b1, &t[t_offset],
ldt, &work[work_offset], ldwork);
i__1 = *k;
for (j = 1; j <= i__1; ++j) {
i__2 = *k - j + 1;
clacgv_(&i__2, &t[j + j * t_dim1], &c__1);
/* L60: */
}
/* C( 1:m, 1:k ) = C( 1:m, 1:k ) - W( 1:m, 1:k ) */
i__1 = *k;
for (j = 1; j <= i__1; ++j) {
i__2 = *m;
for (i__ = 1; i__ <= i__2; ++i__) {
i__3 = i__ + j * c_dim1;
i__4 = i__ + j * c_dim1;
i__5 = i__ + j * work_dim1;
q__1.r = c__[i__4].r - work[i__5].r, q__1.i = c__[i__4].i -
work[i__5].i;
c__[i__3].r = q__1.r, c__[i__3].i = q__1.i;
/* L70: */
}
/* L80: */
}
/* C( 1:m, n-l+1:n ) = C( 1:m, n-l+1:n ) - ...
W( 1:m, 1:k ) * conjg( V( 1:k, 1:l ) ) */
i__1 = *l;
for (j = 1; j <= i__1; ++j) {
clacgv_(k, &v[j * v_dim1 + 1], &c__1);
/* L90: */
}
if (*l > 0) {
q__1.r = -1.f, q__1.i = -0.f;
cgemm_("No transpose", "No transpose", m, l, k, &q__1, &work[
work_offset], ldwork, &v[v_offset], ldv, &c_b1, &c__[(*n
- *l + 1) * c_dim1 + 1], ldc);
}
i__1 = *l;
for (j = 1; j <= i__1; ++j) {
clacgv_(k, &v[j * v_dim1 + 1], &c__1);
/* L100: */
}
}
return 0;
/* End of CLARZB */
} /* clarzb_ */