Contents

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

NAME

     cunglq - generate an M-by-N complex matrix Q with  orthonor-
     mal rows,

SYNOPSIS

     SUBROUTINE CUNGLQ(M, N, K, A, LDA, TAU, WORK, LWORK, INFO)

     COMPLEX A(LDA,*), TAU(*), WORK(*)
     INTEGER M, N, K, LDA, LWORK, INFO

     SUBROUTINE CUNGLQ_64(M, N, K, A, LDA, TAU, WORK, LWORK, INFO)

     COMPLEX A(LDA,*), TAU(*), WORK(*)
     INTEGER*8 M, N, K, LDA, LWORK, INFO

  F95 INTERFACE
     SUBROUTINE UNGLQ(M, [N], [K], A, [LDA], TAU, [WORK], [LWORK], [INFO])

     COMPLEX, DIMENSION(:) :: TAU, WORK
     COMPLEX, DIMENSION(:,:) :: A
     INTEGER :: M, N, K, LDA, LWORK, INFO

     SUBROUTINE UNGLQ_64(M, [N], [K], A, [LDA], TAU, [WORK], [LWORK],
            [INFO])

     COMPLEX, DIMENSION(:) :: TAU, WORK
     COMPLEX, DIMENSION(:,:) :: A
     INTEGER(8) :: M, N, K, LDA, LWORK, INFO

  C INTERFACE
     #include <sunperf.h>

     void cunglq(int m, int n, int k, complex *a, int  lda,  com-
               plex *tau, int *info);

     void cunglq_64(long m, long n, long k, complex *a, long lda,
               complex *tau, long *info);

PURPOSE

     cunglq generates an M-by-N complex matrix Q with orthonormal
     rows, which is defined as the first M rows of a product of K
     elementary reflectors of order N

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

     as returned by CGELQF.

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 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.  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  ele-
               mentary reflector H(i), as returned by CGELQF.

     WORK (workspace)
               On exit, if INFO = 0, WORK(1) returns the  optimal
               LWORK.

     LWORK (input)
               The  dimension  of  the  array  WORK.   LWORK   >=
               max(1,M).   For optimum performance LWORK >= M*NB,
               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 has an ille-
               gal value