zungr2

NAME

zungr2 - generate an m by n complex matrix Q with orthonormal rows,

SYNOPSIS

  SUBROUTINE ZUNGR2( M, N, K, A, LDA, TAU, WORK, INFO)
  DOUBLE COMPLEX A(LDA,*), TAU(*), WORK(*)
  INTEGER M, N, K, LDA, INFO
 
  SUBROUTINE ZUNGR2_64( M, N, K, A, LDA, TAU, WORK, INFO)
  DOUBLE COMPLEX A(LDA,*), TAU(*), WORK(*)
  INTEGER*8 M, N, K, LDA, INFO

F95 INTERFACE

  SUBROUTINE UNGR2( [M], [N], [K], A, [LDA], TAU, [WORK], [INFO])
  COMPLEX(8), DIMENSION(:) :: TAU, WORK
  COMPLEX(8), DIMENSION(:,:) :: A
  INTEGER :: M, N, K, LDA, INFO
 
  SUBROUTINE UNGR2_64( [M], [N], [K], A, [LDA], TAU, [WORK], [INFO])
  COMPLEX(8), DIMENSION(:) :: TAU, WORK
  COMPLEX(8), DIMENSION(:,:) :: A
  INTEGER(8) :: M, N, K, LDA, INFO

C INTERFACE

#include <sunperf.h>

void zungr2(int m, int n, int k, doublecomplex *a, int lda, doublecomplex *tau, int *info);

void zungr2_64(long m, long n, long k, doublecomplex *a, long lda, doublecomplex *tau, long *info);

PURPOSE

zungr2 generates an m by n complex matrix Q with orthonormal rows, which is defined as the last m rows of a product of k elementary reflectors of order n

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

as returned by CGERQF.

ARGUMENTS

* M (input): The number of rows of the matrix Q. M >= 0.
* N (input): The number of columns of the matrix Q. N >= M.
* K (input): The number of elementary reflectors whose product defines the matrix Q. M >= K >= 0.
* A (input/output): On entry, the (m-k+i)-th row must contain the vector which defines the elementary reflector H(i), for i = 1,2,...,k, as returned by CGERQF in the last k rows of its array argument A. On exit, the m-by-n matrix Q.
* LDA (input): The first dimension of the array A. LDA >= max(1,M).
* TAU (input): TAU(i) must contain the scalar factor of the elementary reflector H(i), as returned by CGERQF.
* WORK (workspace): dimension(M)
* INFO (output)