• NAME
• SYNOPSIS
• F95 INTERFACE
• C INTERFACE
• PURPOSE
• ARGUMENTS

NAME

zunmqr - overwrite the general complex M-by-N matrix C with SIDE = 'L' SIDE = 'R' TRANS = 'N'

SYNOPSIS

  SUBROUTINE ZUNMQR( SIDE, TRANS, M, N, K, A, LDA, TAU, C, LDC, WORK, 
 *      LWORK, INFO)
  CHARACTER * 1 SIDE, TRANS
  DOUBLE COMPLEX A(LDA,*), TAU(*), C(LDC,*), WORK(*)
  INTEGER M, N, K, LDA, LDC, LWORK, INFO

  SUBROUTINE ZUNMQR_64( SIDE, TRANS, M, N, K, A, LDA, TAU, C, LDC, 
 *      WORK, LWORK, INFO)
  CHARACTER * 1 SIDE, TRANS
  DOUBLE COMPLEX A(LDA,*), TAU(*), C(LDC,*), WORK(*)
  INTEGER*8 M, N, K, LDA, LDC, LWORK, INFO

F95 INTERFACE

  SUBROUTINE UNMQR( SIDE, [TRANS], [M], [N], [K], A, [LDA], TAU, C, 
 *       [LDC], [WORK], [LWORK], [INFO])
  CHARACTER(LEN=1) :: SIDE, TRANS
  COMPLEX(8), DIMENSION(:) :: TAU, WORK
  COMPLEX(8), DIMENSION(:,:) :: A, C
  INTEGER :: M, N, K, LDA, LDC, LWORK, INFO

  SUBROUTINE UNMQR_64( SIDE, [TRANS], [M], [N], [K], A, [LDA], TAU, C, 
 *       [LDC], [WORK], [LWORK], [INFO])
  CHARACTER(LEN=1) :: 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 zunmqr(char side, char trans, int m, int n, int k, doublecomplex *a, int lda, doublecomplex *tau, doublecomplex *c, int ldc, int *info);

void zunmqr_64(char side, char trans, long m, long n, long k, doublecomplex *a, long lda, doublecomplex *tau, doublecomplex *c, long ldc, long *info);

PURPOSE

zunmqr overwrites the general complex M-by-N matrix C with TRANS = 'C': Q**H * C C * Q**H

where Q is a complex unitary matrix defined as the product of k elementary reflectors

      Q = H(1) H(2) . . . H(k)

as returned by CGEQRF. Q is of order M if SIDE = 'L' and of order N if SIDE = 'R'.

ARGUMENTS

• SIDE (input)
  

   = 'L': apply Q or Q**H from the Left;

   = 'R': apply Q or Q**H from the Right.

• TRANS (input)
  

   = 'N':  No transpose, apply Q;

   = 'C':  Conjugate transpose, apply Q**H.

• 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)
  The number of elementary reflectors whose product defines the matrix Q. If SIDE = 'L', M > = K > = 0; if SIDE = 'R', N > = K > = 0.

• A (input)
  The i-th column must contain the vector which defines the elementary reflector H(i), for i = 1,2,...,k, as returned by CGEQRF in the first k columns of its array argument A. A is modified by the routine but restored on exit.

• LDA (input)
  The leading dimension of the array A. If SIDE = 'L', LDA > = max(1,M); if SIDE = 'R', LDA > = max(1,N).

• TAU (input)
  TAU(i) must contain the scalar factor of the elementary reflector H(i), as returned by CGEQRF.

• 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.

• 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 performance 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