cunmlq (l) - Linux Man Pages

cunmlq: overwrites the general complex M-by-N matrix C with SIDE = aqLaq SIDE = aqRaq TRANS = aqNaq

NAME

CUNMLQ - overwrites the general complex M-by-N matrix C with SIDE = aqLaq SIDE = aqRaq TRANS = aqNaq

SYNOPSIS

SUBROUTINE CUNMLQ(
SIDE, TRANS, M, N, K, A, LDA, TAU, C, LDC, WORK, LWORK, INFO )

    
CHARACTER SIDE, TRANS

    
INTEGER INFO, K, LDA, LDC, LWORK, M, N

    
COMPLEX A( LDA, * ), C( LDC, * ), TAU( * ), WORK( * )

PURPOSE

CUNMLQ overwrites the general complex M-by-N matrix C with TRANS = aqCaq: Q**H * C C * Q**H
where Q is a complex unitary matrix defined as the product of k elementary reflectors

H(k)aq . . . H(2)aq H(1)aq
as returned by CGELQF. Q is of order M if SIDE = aqLaq and of order N if SIDE = aqRaq.

ARGUMENTS

SIDE (input) CHARACTER*1
= aqLaq: apply Q or Q**H from the Left;
= aqRaq: apply Q or Q**H from the Right.
TRANS (input) CHARACTER*1

= aqNaq: No transpose, apply Q;
= aqCaq: Conjugate transpose, apply Q**H.
M (input) INTEGER
The number of rows of the matrix C. M >= 0.
N (input) INTEGER
The number of columns of the matrix C. N >= 0.
K (input) INTEGER
The number of elementary reflectors whose product defines the matrix Q. If SIDE = aqLaq, M >= K >= 0; if SIDE = aqRaq, N >= K >= 0.
A (input) COMPLEX array, dimension
(LDA,M) if SIDE = aqLaq, (LDA,N) if SIDE = aqRaq The i-th row must contain the vector which defines the elementary reflector H(i), for i = 1,2,...,k, as returned by CGELQF in the first k rows of its array argument A. A is modified by the routine but restored on exit.
LDA (input) INTEGER
The leading dimension of the array A. LDA >= max(1,K).
TAU (input) COMPLEX array, dimension (K)
TAU(i) must contain the scalar factor of the elementary reflector H(i), as returned by CGELQF.
C (input/output) COMPLEX array, dimension (LDC,N)
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.
LDC (input) INTEGER
The leading dimension of the array C. LDC >= max(1,M).
WORK (workspace/output) COMPLEX array, dimension (MAX(1,LWORK))
On exit, if INFO = 0, WORK(1) returns the optimal LWORK.
LWORK (input) INTEGER
The dimension of the array WORK. If SIDE = aqLaq, LWORK >= max(1,N); if SIDE = aqRaq, LWORK >= max(1,M). For optimum performance LWORK >= N*NB if SIDE aqLaq, and LWORK >= M*NB if SIDE = aqRaq, 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) INTEGER
= 0: successful exit
< 0: if INFO = -i, the i-th argument had an illegal value