Contents


NAME

     sorgql - generate an M-by-N real matrix Q  with  orthonormal
     columns,

SYNOPSIS

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

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

     SUBROUTINE SORGQL_64(M, N, K, A, LDA, TAU, WORK, LDWORK, INFO)

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

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

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

     SUBROUTINE ORGQL_64(M, [N], [K], A, [LDA], TAU, [WORK], [LDWORK],
            [INFO])

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

  C INTERFACE
     #include <sunperf.h>

     void sorgql(int m, int n, int k, float *a,  int  lda,  float
               *tau, int *info);

     void sorgql_64(long m, long n, long k, float *a,  long  lda,
               float *tau, long *info);

PURPOSE

     sorgql generates an M-by-N real matrix  Q  with  orthonormal
     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 SGEQLF.

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 SGEQLF  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 SGEQLF.

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

     LDWORK (input)
               The  dimension  of  the  array  WORK.  LDWORK   >=
               max(1,N).  For optimum performance LDWORK >= N*NB,
               where NB is the optimal blocksize.

               If LDWORK = -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 LDWORK is issued by XERBLA.

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