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

NAME

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

SYNOPSIS

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

  SUBROUTINE ZUNMTR_64( SIDE, UPLO, TRANS, M, N, A, LDA, TAU, C, LDC, 
 *      WORK, LWORK, INFO)
  CHARACTER * 1 SIDE, UPLO, TRANS
  DOUBLE COMPLEX A(LDA,*), TAU(*), C(LDC,*), WORK(*)
  INTEGER*8 M, N, LDA, LDC, LWORK, INFO

F95 INTERFACE

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

  SUBROUTINE UNMTR_64( SIDE, UPLO, [TRANS], [M], [N], A, [LDA], TAU, 
 *       C, [LDC], [WORK], [LWORK], [INFO])
  CHARACTER(LEN=1) :: SIDE, UPLO, TRANS
  COMPLEX(8), DIMENSION(:) :: TAU, WORK
  COMPLEX(8), DIMENSION(:,:) :: A, C
  INTEGER(8) :: M, N, LDA, LDC, LWORK, INFO

C INTERFACE

#include <sunperf.h>

void zunmtr(char side, char uplo, char trans, int m, int n, doublecomplex *a, int lda, doublecomplex *tau, doublecomplex *c, int ldc, int *info);

void zunmtr_64(char side, char uplo, char trans, long m, long n, doublecomplex *a, long lda, doublecomplex *tau, doublecomplex *c, long ldc, long *info);

PURPOSE

zunmtr 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 of order nq, with nq = m if SIDE = 'L' and nq = n if SIDE = 'R'. Q is defined as the product of nq-1 elementary reflectors, as returned by CHETRD:

if UPLO = 'U', Q = H(nq-1) . . . H(2) H(1);

if UPLO = 'L', Q = H(1) H(2) . . . H(nq-1).

ARGUMENTS

• SIDE (input)
  

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

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

• UPLO (input)
  

   = 'U': Upper triangle of A contains elementary reflectors
  from CHETRD;
   = 'L': Lower triangle of A contains elementary reflectors
  from CHETRD.

• 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.

• A (input)
  (LDA,M) if SIDE = 'L' (LDA,N) if SIDE = 'R' The vectors which define the elementary reflectors, as returned by CHETRD.

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

• TAU (input)
  (M-1) if SIDE = 'L' (N-1) if SIDE = 'R' TAU(i) must contain the scalar factor of the elementary reflector H(i), as returned by CHETRD.

• 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