zlarzb(3P) Sun Performance Library zlarzb(3P)NAMEzlarzb - applie a complex block reflector H or its transpose H**H to a
complex distributed M-by-N C from the left or the right
SYNOPSIS
SUBROUTINE ZLARZB(SIDE, TRANS, DIRECT, STOREV, M, N, K, L, V, LDV, T,
LDT, C, LDC, WORK, LDWORK)
CHARACTER * 1 SIDE, TRANS, DIRECT, STOREV
DOUBLE COMPLEX V(LDV,*), T(LDT,*), C(LDC,*), WORK(LDWORK,*)
INTEGER M, N, K, L, LDV, LDT, LDC, LDWORK
SUBROUTINE ZLARZB_64(SIDE, TRANS, DIRECT, STOREV, M, N, K, L, V, LDV,
T, LDT, C, LDC, WORK, LDWORK)
CHARACTER * 1 SIDE, TRANS, DIRECT, STOREV
DOUBLE COMPLEX V(LDV,*), T(LDT,*), C(LDC,*), WORK(LDWORK,*)
INTEGER*8 M, N, K, L, LDV, LDT, LDC, LDWORK
F95 INTERFACE
SUBROUTINE LARZB(SIDE, TRANS, DIRECT, STOREV, [M], [N], K, L, V, [LDV],
T, [LDT], C, [LDC], [WORK], [LDWORK])
CHARACTER(LEN=1) :: SIDE, TRANS, DIRECT, STOREV
COMPLEX(8), DIMENSION(:,:) :: V, T, C, WORK
INTEGER :: M, N, K, L, LDV, LDT, LDC, LDWORK
SUBROUTINE LARZB_64(SIDE, TRANS, DIRECT, STOREV, [M], [N], K, L, V,
[LDV], T, [LDT], C, [LDC], [WORK], [LDWORK])
CHARACTER(LEN=1) :: SIDE, TRANS, DIRECT, STOREV
COMPLEX(8), DIMENSION(:,:) :: V, T, C, WORK
INTEGER(8) :: M, N, K, L, LDV, LDT, LDC, LDWORK
C INTERFACE
#include <sunperf.h>
void zlarzb(char side, char trans, char direct, char storev, int m, int
n, int k, int l, doublecomplex *v, int ldv, doublecomplex *t,
int ldt, doublecomplex *c, int ldc, int ldwork);
void zlarzb_64(char side, char trans, char direct, char storev, long m,
long n, long k, long l, doublecomplex *v, long ldv, double‐
complex *t, long ldt, doublecomplex *c, long ldc, long
ldwork);
PURPOSEzlarzb 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)
= 'L': apply H or H' from the Left
= 'R': apply H or H' from the Right
TRANS (input)
= 'N': apply H (No transpose)
= 'C': apply H' (Conjugate transpose)
DIRECT (input)
Indicates how H is formed from a product of elementary
reflectors = 'F': H = H(1)H(2) . . . H(k) (Forward, not sup‐
ported yet)
= 'B': H = H(k) . . . H(2)H(1) (Backward)
STOREV (input)
Indicates how the vectors which define the elementary reflec‐
tors are stored:
= 'C': Columnwise (not supported yet)
= 'R': Rowwise
M (input) The number of rows of the matrix C.
N (input) The number of columns of the matrix C.
K (input) The order of the matrix T (= the number of elementary reflec‐
tors whose product defines the block reflector).
L (input) The number of columns of the matrix V containing the meaning‐
ful part of the Householder reflectors. If SIDE = 'L', M >=
L >= 0, if SIDE = 'R', N >= L >= 0.
V (input) COMPLEX*16 array of dimension (LDV,NV). If STOREV = 'C', NV
= K; if STOREV = 'R', NV = L.
LDV (input)
The leading dimension of the array V. If STOREV = 'C', LDV
>= L; if STOREV = 'R', LDV >= K.
T (input) The triangular K-by-K matrix T in the representation of the
block reflector.
LDT (input)
The leading dimension of the array T. LDT >= K.
C (input/output)
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)
The leading dimension of the array C. LDC >= max(1,M).
WORK (workspace)
dimension(MAX(M,N),K)
LDWORK (input)
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
6 Mar 2009 zlarzb(3P)
