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CentOS 7.0 - man page for dormbr (centos section 3)

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dormbr.f(3)				      LAPACK				      dormbr.f(3)

NAME
       dormbr.f -

SYNOPSIS
   Functions/Subroutines
       subroutine dormbr (VECT, SIDE, TRANS, M, N, K, A, LDA, TAU, C, LDC, WORK, LWORK, INFO)
	   DORMBR

Function/Subroutine Documentation
   subroutine dormbr (characterVECT, characterSIDE, characterTRANS, integerM, integerN, integerK,
       double precision, dimension( lda, * )A, integerLDA, double precision, dimension( * )TAU,
       double precision, dimension( ldc, * )C, integerLDC, double precision, dimension( * )WORK,
       integerLWORK, integerINFO)
       DORMBR

       Purpose:

	    If VECT = 'Q', DORMBR overwrites the general real M-by-N matrix C
	    with
			    SIDE = 'L'	   SIDE = 'R'
	    TRANS = 'N':      Q * C	     C * Q
	    TRANS = 'T':      Q**T * C	     C * Q**T

	    If VECT = 'P', DORMBR overwrites the general real M-by-N matrix C
	    with
			    SIDE = 'L'	   SIDE = 'R'
	    TRANS = 'N':      P * C	     C * P
	    TRANS = 'T':      P**T * C	     C * P**T

	    Here Q and P**T are the orthogonal matrices determined by DGEBRD 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) and G(i)
	    respectively.

	    Let nq = m if SIDE = 'L' and nq = n if SIDE = 'R'. Thus nq is the
	    order of the orthogonal matrix Q or P**T that is applied.

	    If VECT = 'Q', A is assumed to have been an NQ-by-K matrix:
	    if nq >= k, Q = H(1) H(2) . . . H(k);
	    if nq < k, Q = H(1) H(2) . . . H(nq-1).

	    If VECT = 'P', A is assumed to have been a K-by-NQ matrix:
	    if k < nq, P = G(1) G(2) . . . G(k);
	    if k >= nq, P = G(1) G(2) . . . G(nq-1).

       Parameters:
	   VECT

		     VECT is CHARACTER*1
		     = 'Q': apply Q or Q**T;
		     = 'P': apply P or P**T.

	   SIDE

		     SIDE is CHARACTER*1
		     = 'L': apply Q, Q**T, P or P**T from the Left;
		     = 'R': apply Q, Q**T, P or P**T from the Right.

	   TRANS

		     TRANS is CHARACTER*1
		     = 'N':  No transpose, apply Q  or P;
		     = 'T':  Transpose, apply Q**T or P**T.

	   M

		     M is INTEGER
		     The number of rows of the matrix C. M >= 0.

	   N

		     N is INTEGER
		     The number of columns of the matrix C. N >= 0.

	   K

		     K is INTEGER
		     If VECT = 'Q', the number of columns in the original
		     matrix reduced by DGEBRD.
		     If VECT = 'P', the number of rows in the original
		     matrix reduced by DGEBRD.
		     K >= 0.

	   A

		     A is DOUBLE PRECISION array, dimension
					   (LDA,min(nq,K)) if VECT = 'Q'
					   (LDA,nq)	   if VECT = 'P'
		     The vectors which define the elementary reflectors H(i) and
		     G(i), whose products determine the matrices Q and P, as
		     returned by DGEBRD.

	   LDA

		     LDA is INTEGER
		     The leading dimension of the array A.
		     If VECT = 'Q', LDA >= max(1,nq);
		     if VECT = 'P', LDA >= max(1,min(nq,K)).

	   TAU

		     TAU is DOUBLE PRECISION array, dimension (min(nq,K))
		     TAU(i) must contain the scalar factor of the elementary
		     reflector H(i) or G(i) which determines Q or P, as returned
		     by DGEBRD in the array argument TAUQ or TAUP.

	   C

		     C is DOUBLE PRECISION array, dimension (LDC,N)
		     On entry, the M-by-N matrix C.
		     On exit, C is overwritten by Q*C or Q**T*C or C*Q**T or C*Q
		     or P*C or P**T*C or C*P or C*P**T.

	   LDC

		     LDC is INTEGER
		     The leading dimension of the array C. LDC >= max(1,M).

	   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.
		     If SIDE = 'L', LWORK >= max(1,N);
		     if SIDE = 'R', LWORK >= max(1,M).
		     For optimum performance LWORK >= N*NB if SIDE = 'L', and
		     LWORK >= M*NB if SIDE = 'R', 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 195 of file dormbr.f.

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

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