dgerqf man page on OpenIndiana

Man page or keyword search:  
man Server   20441 pages
apropos Keyword Search (all sections)
Output format
OpenIndiana logo
[printable version]

dgerqf(3P)		    Sun Performance Library		    dgerqf(3P)

NAME
       dgerqf - compute an RQ factorization of a real M-by-N matrix A

SYNOPSIS
       SUBROUTINE DGERQF(M, N, A, LDA, TAU, WORK, LDWORK, INFO)

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

       SUBROUTINE DGERQF_64(M, N, A, LDA, TAU, WORK, LDWORK, INFO)

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

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

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

       SUBROUTINE GERQF_64([M], [N], A, [LDA], TAU, [WORK], [LDWORK], [INFO])

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

   C INTERFACE
       #include <sunperf.h>

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

       void  dgerqf_64(long  m, long n, double *a, long lda, double *tau, long
		 *info);

PURPOSE
       dgerqf computes an RQ factorization of a real M-by-N matrix A: A = R  *
       Q.

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

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

       A (input/output)
		 On entry, the M-by-N matrix A.	 On exit, if m <= n, the upper
		 triangle of the subarray A(1:m,n-m+1:n) contains  the	M-by-M
		 upper	triangular  matrix  R;	if m >= n, the elements on and
		 above the  (m-n)-th  subdiagonal  contain  the	 M-by-N	 upper
		 trapezoidal  matrix R; the remaining elements, with the array
		 TAU, represent the  orthogonal	 matrix	 Q  as	a  product  of
		 min(m,n) elementary reflectors (see Further Details).

       LDA (input)
		 The leading dimension of the array A.	LDA >= max(1,M).

       TAU (output)
		 The  scalar factors of the elementary reflectors (see Further
		 Details).

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

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

		 If LDWORK = -1, then a workspace query is assumed;  the  rou‐
		 tine  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 had an illegal value

FURTHER DETAILS
       The matrix Q is represented as a product of elementary reflectors

	  Q = H(1) H(2) . . . H(k), where k = min(m,n).

       Each H(i) has the form

	  H(i) = I - tau * v * v'

       where tau is a real scalar, and v is a real vector with
       v(n-k+i+1:n)  =	0  and v(n-k+i) = 1; v(1:n-k+i-1) is stored on exit in
       A(m-k+i,1:n-k+i-1), and tau in TAU(i).

				  6 Mar 2009			    dgerqf(3P)
[top]

List of man pages available for OpenIndiana

Copyright (c) for man pages and the logo by the respective OS vendor.

For those who want to learn more, the polarhome community provides shell access and support.

[legal] [privacy] [GNU] [policy] [cookies] [netiquette] [sponsors] [FAQ]
Tweet
Polarhome, production since 1999.
Member of Polarhome portal.
Based on Fawad Halim's script.
....................................................................
Vote for polarhome
Free Shell Accounts :: the biggest list on the net