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dorgtr.f(3)				      LAPACK				      dorgtr.f(3)

NAME
       dorgtr.f -

SYNOPSIS
   Functions/Subroutines
       subroutine dorgtr (UPLO, N, A, LDA, TAU, WORK, LWORK, INFO)
	   DORGTR

Function/Subroutine Documentation
   subroutine dorgtr (characterUPLO, integerN, double precision, dimension( lda, * )A,
       integerLDA, double precision, dimension( * )TAU, double precision, dimension( * )WORK,
       integerLWORK, integerINFO)
       DORGTR

       Purpose:

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

	    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 DSYTRD;
		     = 'L': Lower triangle of A contains elementary reflectors
			    from DSYTRD.

	   N

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

	   A

		     A is DOUBLE PRECISION array, dimension (LDA,N)
		     On entry, the vectors which define the elementary reflectors,
		     as returned by DSYTRD.
		     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 DOUBLE PRECISION array, dimension (N-1)
		     TAU(i) must contain the scalar factor of the elementary
		     reflector H(i), as returned by DSYTRD.

	   WORK

		     WORK is DOUBLE PRECISION 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 dorgtr.f.

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

Version 3.4.2				 Tue Sep 25 2012			      dorgtr.f(3)
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