Contents

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

NAME

     dorg2r - generate an m by n real matrix Q  with  orthonormal
     columns,

SYNOPSIS

     SUBROUTINE DORG2R(M, N, K, A, LDA, TAU, WORK, INFO)

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

     SUBROUTINE DORG2R_64(M, N, K, A, LDA, TAU, WORK, INFO)

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

  F95 INTERFACE
     SUBROUTINE ORG2R([M], [N], [K], A, [LDA], TAU, [WORK], [INFO])

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

     SUBROUTINE ORG2R_64([M], [N], [K], A, [LDA], TAU, [WORK], [INFO])

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

  C INTERFACE
     #include <sunperf.h>

     void dorg2r(int m, int n, int k, double *a, int lda,  double
               *tau, int *info);

     void dorg2r_64(long m, long n, long k, double *a, long  lda,
               double *tau, long *info);

PURPOSE

     dorg2r R generates an m by n real matrix Q with  orthonormal
     columns,  which  is defined as the first n columns of a pro-
     duct of k elementary reflectors of order m

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

     as returned by SGEQRF.

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 i-th column must contain the  vector
               which defines the elementary reflector H(i), for i
               = 1,2,...,k, as returned by SGEQRF in the first  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 SGEQRF.

     WORK (workspace)
               dimension(N)

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