Home Man
Search
Today's Posts
Register

Linux & Unix Commands - Search Man Pages

RedHat 9 (Linux i386) - man page for sorgbr (redhat section l)

SORGBR(l)					)					SORGBR(l)

NAME
       SORGBR  - generate one of the real orthogonal matrices Q or P**T determined by SGEBRD when
       reducing a real matrix A to bidiagonal form

SYNOPSIS
       SUBROUTINE SORGBR( VECT, M, N, K, A, LDA, TAU, WORK, LWORK, INFO )

	   CHARACTER	  VECT

	   INTEGER	  INFO, K, LDA, LWORK, M, N

	   REAL 	  A( LDA, * ), TAU( * ), WORK( * )

PURPOSE
       SORGBR generates one of the real orthogonal matrices Q or P**T determined by  SGEBRD  when
       reducing  a  real matrix A to bidiagonal form: A = Q * B * P**T. Q and P**T are defined as
       products of elementary reflectors H(i) or G(i) respectively.

       If VECT = 'Q', A is assumed to have been an M-by-K matrix, and Q is of order M:
       if m >= k, Q = H(1) H(2) . . . H(k) and SORGBR returns the first n columns of Q,  where	m
       >= n >= k;
       if m < k, Q = H(1) H(2) . . . H(m-1) and SORGBR returns Q as an M-by-M matrix.

       If VECT = 'P', A is assumed to have been a K-by-N matrix, and P**T is of order N:
       if k < n, P**T = G(k) . . . G(2) G(1) and SORGBR returns the first m rows of P**T, where n
       >= m >= k;
       if k >= n, P**T = G(n-1) . . . G(2) G(1) and SORGBR returns P**T as an N-by-N matrix.

ARGUMENTS
       VECT    (input) CHARACTER*1
	       Specifies whether the matrix Q or the matrix P**T is required, as defined  in  the
	       transformation applied by SGEBRD:
	       = 'Q':  generate Q;
	       = 'P':  generate P**T.

       M       (input) INTEGER
	       The number of rows of the matrix Q or P**T to be returned.  M >= 0.

       N       (input) INTEGER
	       The  number of columns of the matrix Q or P**T to be returned.  N >= 0.	If VECT =
	       'Q', M >= N >= min(M,K); if VECT = 'P', N >= M >= min(N,K).

       K       (input) INTEGER
	       If VECT = 'Q', the number of columns in the original M-by-K matrix reduced by SGE-
	       BRD.   If  VECT = 'P', the number of rows in the original K-by-N matrix reduced by
	       SGEBRD.	K >= 0.

       A       (input/output) REAL array, dimension (LDA,N)
	       On entry, the vectors which define the elementary reflectors, as returned by  SGE-
	       BRD.  On exit, the M-by-N matrix Q or P**T.

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

       TAU     (input) REAL array, dimension
	       (min(M,K))  if  VECT = 'Q' (min(N,K)) if VECT = 'P' TAU(i) must contain the scalar
	       factor of the elementary reflector H(i) or G(i), which determines Q  or	P**T,  as
	       returned by SGEBRD in its array argument TAUQ or TAUP.

       WORK    (workspace/output) REAL array, dimension (LWORK)
	       On exit, if INFO = 0, WORK(1) returns the optimal LWORK.

       LWORK   (input) INTEGER
	       The  dimension  of  the array WORK. LWORK >= max(1,min(M,N)).  For optimum perfor-
	       mance LWORK >= min(M,N)*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) INTEGER
	       = 0:  successful exit
	       < 0:  if INFO = -i, the i-th argument had an illegal value

LAPACK version 3.0			   15 June 2000 				SORGBR(l)


All times are GMT -4. The time now is 05:05 AM.

Unix & Linux Forums Content Copyrightę1993-2018. All Rights Reserved.
UNIX.COM Login
Username:
Password:  
Show Password