Contents

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

NAME

     cung2l - generate an m by n complex matrix Q with  orthonor-
     mal columns,

SYNOPSIS

     SUBROUTINE CUNG2L(M, N, K, A, LDA, TAU, WORK, INFO)

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

     SUBROUTINE CUNG2L_64(M, N, K, A, LDA, TAU, WORK, INFO)

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

  F95 INTERFACE
     SUBROUTINE UNG2L(M, [N], [K], A, [LDA], TAU, [WORK], [INFO])

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

     SUBROUTINE UNG2L_64(M, [N], [K], A, [LDA], TAU, [WORK], [INFO])

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

  C INTERFACE
     #include <sunperf.h>

     void cung2l(int m, int n, int k, complex *a, int  lda,  com-
               plex *tau, int *info);

     void cung2l_64(long m, long n, long k, complex *a, long lda,
               complex *tau, long *info);

PURPOSE

     cung2l L generates an m by n complex matrix Q with orthonor-
     mal  columns,  which  is  defined as the last n columns of a
     product of k elementary reflectors of order m

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

     as returned by CGEQLF.

ARGUMENTS

     M (input) The number of rows of the matrix Q. M >= 0.

     N (input) The number of columns of the matrix Q. M >=  N  >=
               0.

     K (input) The number of elementary reflectors whose  product
               defines the matrix Q. N >= K >= 0.

     A (input/output)
               On entry, the (n-k+i)-th column must  contain  the
               vector  which  defines  the  elementary  reflector
               H(i), for i = 1,2,...,k, as returned by CGEQLF  in
               the  last  k  columns 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 CGEQLF.

     WORK (workspace)
               dimension(N)

     INFO (output)
               = 0: successful exit
               < 0: if INFO = -i, the i-th argument has an  ille-
               gal value