zunmbr(3P) Sun Performance Library zunmbr(3P)NAMEzunmbr - overwrites the general complex M-by-N matrix C Q*C or Q**H*C
or C*Q**H or C*Q or P*C or P**H*C or C*P or C*P**H.
SYNOPSIS
SUBROUTINE ZUNMBR(VECT, SIDE, TRANS, M, N, K, A, LDA, TAU, C, LDC,
WORK, LWORK, INFO)
CHARACTER * 1 VECT, SIDE, TRANS
DOUBLE COMPLEX A(LDA,*), TAU(*), C(LDC,*), WORK(*)
INTEGER M, N, K, LDA, LDC, LWORK, INFO
SUBROUTINE ZUNMBR_64(VECT, SIDE, TRANS, M, N, K, A, LDA, TAU, C, LDC,
WORK, LWORK, INFO)
CHARACTER * 1 VECT, SIDE, TRANS
DOUBLE COMPLEX A(LDA,*), TAU(*), C(LDC,*), WORK(*)
INTEGER*8 M, N, K, LDA, LDC, LWORK, INFO
F95 INTERFACE
SUBROUTINE UNMBR(VECT, SIDE, [TRANS], [M], [N], K, A, [LDA], TAU, C,
[LDC], [WORK], [LWORK], [INFO])
CHARACTER(LEN=1) :: VECT, SIDE, TRANS
COMPLEX(8), DIMENSION(:) :: TAU, WORK
COMPLEX(8), DIMENSION(:,:) :: A, C
INTEGER :: M, N, K, LDA, LDC, LWORK, INFO
SUBROUTINE UNMBR_64(VECT, SIDE, [TRANS], [M], [N], K, A, [LDA], TAU,
C, [LDC], [WORK], [LWORK], [INFO])
CHARACTER(LEN=1) :: VECT, SIDE, TRANS
COMPLEX(8), DIMENSION(:) :: TAU, WORK
COMPLEX(8), DIMENSION(:,:) :: A, C
INTEGER(8) :: M, N, K, LDA, LDC, LWORK, INFO
C INTERFACE
#include <sunperf.h>
void zunmbr(char vect, char side, char trans, int m, int n, int k, dou‐
blecomplex *a, int lda, doublecomplex *tau, doublecomplex *c,
int ldc, int *info);
void zunmbr_64(char vect, char side, char trans, long m, long n, long
k, doublecomplex *a, long lda, doublecomplex *tau, doublecom‐
plex *c, long ldc, long *info);
PURPOSE
If VECT = 'Q', ZUNMBR overwrites the general complex M-by-N matrix C
with
SIDE = 'L' SIDE = 'R'
TRANS = 'N': Q * C C * Q
TRANS = 'C': Q**H * C C * Q**H
If VECT = 'P', ZUNMBR overwrites the general complex M-by-N matrix C
with
SIDE = 'L' SIDE = 'R'
TRANS = 'N': P * C C * P
TRANS = 'C': P**H * C C * P**H
Here Q and P**H are the unitary matrices determined by ZGEBRD when
reducing a complex matrix A to bidiagonal form: A = Q * B * P**H. Q and
P**H are defined as products of elementary reflectors H(i) and G(i)
respectively.
Let nq = m if SIDE = 'L' and nq = n if SIDE = 'R'. Thus nq is the order
of the unitary matrix Q or P**H that is applied.
If VECT = 'Q', A is assumed to have been an NQ-by-K matrix: if nq >= k,
Q = H(1)H(2) . . . H(k);
if nq < k, Q = H(1)H(2) . . . H(nq-1).
If VECT = 'P', A is assumed to have been a K-by-NQ matrix: if k < nq, P
= G(1)G(2) . . . G(k);
if k >= nq, P = G(1)G(2) . . . G(nq-1).
ARGUMENTS
VECT (input)
= 'Q': apply Q or Q**H;
= 'P': apply P or P**H.
SIDE (input)
= 'L': apply Q, Q**H, P or P**H from the Left;
= 'R': apply Q, Q**H, P or P**H from the Right.
TRANS (input)
= 'N': No transpose, apply Q or P;
= 'C': Conjugate transpose, apply Q**H or P**H.
TRANS is defaulted to 'N' for F95 INTERFACE.
M (input) The number of rows of the matrix C. M >= 0.
N (input) The number of columns of the matrix C. N >= 0.
K (input) If VECT = 'Q', the number of columns in the original matrix
reduced by ZGEBRD. If VECT = 'P', the number of rows in the
original matrix reduced by ZGEBRD. K >= 0.
A (input) (LDA,min(nq,K)) if VECT = 'Q' (LDA,nq) if VECT = 'P'
The vectors which define the elementary reflectors H(i) and
G(i), whose products determine the matrices Q and P, as
returned by ZGEBRD.
LDA (input)
The leading dimension of the array A. If VECT = 'Q', LDA >=
max(1,nq); if VECT = 'P', LDA >= max(1,min(nq,K)).
TAU (input)
TAU(i) must contain the scalar factor of the elementary
reflector H(i) or G(i) which determines Q or P, as returned
by ZGEBRD in the array argument TAUQ or TAUP.
C (input/output)
On entry, the M-by-N matrix C. On exit, C is overwritten by
Q*C or Q**H*C or C*Q**H or C*Q or P*C or P**H*C or C*P or
C*P**H.
LDC (input)
The leading dimension of the array C. LDC >= max(1,M).
WORK (workspace)
On exit, if INFO = 0, WORK(1) returns the optimal LWORK.
LWORK (input)
The dimension of the array WORK. If SIDE = 'L', LWORK >=
max(1,N); if SIDE = 'R', LWORK >= max(1,M). For optimum per‐
formance LWORK >= N*NB if SIDE = 'L', and LWORK >= M*NB if
SIDE = 'R', where NB is the optimal blocksize.
If LWORK = -1, then a workspace query is assumed; the routine
only calculates the optimal size of the WORK array, returns
this value as the first entry of the WORK array, and no error
message related to LWORK is issued by XERBLA.
INFO (output)
= 0: successful exit
< 0: if INFO = -i, the i-th argument had an illegal value
6 Mar 2009 zunmbr(3P)
