sorgtr.f(3) [debian man page]

sorgtr.f(3)							      LAPACK							       sorgtr.f(3)

NAME

       sorgtr.f -

SYNOPSIS

   Functions/Subroutines
       subroutine sorgtr (UPLO, N, A, LDA, TAU, WORK, LWORK, INFO)
	   SORGTR

Function/Subroutine Documentation
   subroutine sorgtr (characterUPLO, integerN, real, dimension( lda, * )A, integerLDA, real, dimension( * )TAU, real, dimension( * )WORK,
       integerLWORK, integerINFO)
       SORGTR

       Purpose:

	    SORGTR generates a real orthogonal matrix Q which is defined as the
	    product of n-1 elementary reflectors of order N, as returned by
	    SSYTRD:

	    if UPLO = 'U', Q = H(n-1) . . . H(2) H(1),

	    if UPLO = 'L', Q = H(1) H(2) . . . H(n-1).

       Parameters:
	   UPLO

		     UPLO is CHARACTER*1
		     = 'U': Upper triangle of A contains elementary reflectors
			    from SSYTRD;
		     = 'L': Lower triangle of A contains elementary reflectors
			    from SSYTRD.

	   N

		     N is INTEGER
		     The order of the matrix Q. N >= 0.

	   A

		     A is REAL array, dimension (LDA,N)
		     On entry, the vectors which define the elementary reflectors,
		     as returned by SSYTRD.
		     On exit, the N-by-N orthogonal matrix Q.

	   LDA

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

	   TAU

		     TAU is REAL array, dimension (N-1)
		     TAU(i) must contain the scalar factor of the elementary
		     reflector H(i), as returned by SSYTRD.

	   WORK

		     WORK is REAL array, dimension (MAX(1,LWORK))
		     On exit, if INFO = 0, WORK(1) returns the optimal LWORK.

	   LWORK

		     LWORK is INTEGER
		     The dimension of the array WORK. LWORK >= max(1,N-1).
		     For optimum performance LWORK >= (N-1)*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

		     INFO is INTEGER
		     = 0:  successful exit
		     < 0:  if INFO = -i, the i-th argument had an illegal value

       Author:
	   Univ. of Tennessee

	   Univ. of California Berkeley

	   Univ. of Colorado Denver

	   NAG Ltd.

       Date:
	   November 2011

       Definition at line 124 of file sorgtr.f.

Author
       Generated automatically by Doxygen for LAPACK from the source code.

Version 3.4.1							  Sun May 26 2013						       sorgtr.f(3)

Check Out this Related Man Page

SORGTR(l)								 )								 SORGTR(l)

NAME

       SORGTR - generate a real orthogonal matrix Q which is defined as the product of n-1 elementary reflectors of order N, as returned by SSYTRD

SYNOPSIS

       SUBROUTINE SORGTR( UPLO, N, A, LDA, TAU, WORK, LWORK, INFO )

	   CHARACTER	  UPLO

	   INTEGER	  INFO, LDA, LWORK, N

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

PURPOSE

       SORGTR generates a real orthogonal matrix Q which is defined as the product of n-1 elementary reflectors of order N, as returned by SSYTRD:
       if UPLO = 'U', Q = H(n-1) . . . H(2) H(1),

       if UPLO = 'L', Q = H(1) H(2) . . . H(n-1).

ARGUMENTS

       UPLO    (input) CHARACTER*1
	       = 'U': Upper triangle of A contains elementary reflectors from SSYTRD; = 'L': Lower triangle of A  contains  elementary	reflectors
	       from SSYTRD.

       N       (input) INTEGER
	       The order of the matrix Q. N >= 0.

       A       (input/output) REAL array, dimension (LDA,N)
	       On entry, the vectors which define the elementary reflectors, as returned by SSYTRD.  On exit, the N-by-N orthogonal matrix Q.

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

       TAU     (input) REAL array, dimension (N-1)
	       TAU(i) must contain the scalar factor of the elementary reflector H(i), as returned by SSYTRD.

       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,N-1).  For optimum performance LWORK >= (N-1)*NB, where NB is the optimal block-
	       size.

	       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 							 SORGTR(l)

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