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dlaqp2(3) [centos man page]

dlaqp2.f(3)							      LAPACK							       dlaqp2.f(3)

NAME

       dlaqp2.f -

SYNOPSIS

   Functions/Subroutines
       subroutine dlaqp2 (M, N, OFFSET, A, LDA, JPVT, TAU, VN1, VN2, WORK)
	   DLAQP2 computes a QR factorization with column pivoting of the matrix block.

Function/Subroutine Documentation
   subroutine dlaqp2 (integerM, integerN, integerOFFSET, double precision, dimension( lda, * )A, integerLDA, integer, dimension( * )JPVT, double
       precision, dimension( * )TAU, double precision, dimension( * )VN1, double precision, dimension( * )VN2, double precision, dimension( *
       )WORK)
       DLAQP2 computes a QR factorization with column pivoting of the matrix block.

       Purpose:

	    DLAQP2 computes a QR factorization with column pivoting of
	    the block A(OFFSET+1:M,1:N).
	    The block A(1:OFFSET,1:N) is accordingly pivoted, but not factorized.

       Parameters:
	   M

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

	   N

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

	   OFFSET

		     OFFSET is INTEGER
		     The number of rows of the matrix A that must be pivoted
		     but no factorized. OFFSET >= 0.

	   A

		     A is DOUBLE PRECISION array, dimension (LDA,N)
		     On entry, the M-by-N matrix A.
		     On exit, the upper triangle of block A(OFFSET+1:M,1:N) is
		     the triangular factor obtained; the elements in block
		     A(OFFSET+1:M,1:N) below the diagonal, together with the
		     array TAU, represent the orthogonal matrix Q as a product of
		     elementary reflectors. Block A(1:OFFSET,1:N) has been
		     accordingly pivoted, but no factorized.

	   LDA

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

	   JPVT

		     JPVT is INTEGER array, dimension (N)
		     On entry, if JPVT(i) .ne. 0, the i-th column of A is permuted
		     to the front of A*P (a leading column); if JPVT(i) = 0,
		     the i-th column of A is a free column.
		     On exit, if JPVT(i) = k, then the i-th column of A*P
		     was the k-th column of A.

	   TAU

		     TAU is DOUBLE PRECISION array, dimension (min(M,N))
		     The scalar factors of the elementary reflectors.

	   VN1

		     VN1 is DOUBLE PRECISION array, dimension (N)
		     The vector with the partial column norms.

	   VN2

		     VN2 is DOUBLE PRECISION array, dimension (N)
		     The vector with the exact column norms.

	   WORK

		     WORK is DOUBLE PRECISION array, dimension (N)

       Author:
	   Univ. of Tennessee

	   Univ. of California Berkeley

	   Univ. of Colorado Denver

	   NAG Ltd.

       Date:
	   September 2012

       Contributors:
	   G. Quintana-Orti, Depto. de Informatica, Universidad Jaime I, Spain X. Sun, Computer Science Dept., Duke University, USA
	    Partial column norm updating strategy modified on April 2011 Z. Drmac and Z. Bujanovic, Dept. of Mathematics, University of Zagreb,
	   Croatia.

       References:
	   LAPACK Working Note 176

       Definition at line 149 of file dlaqp2.f.

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

Version 3.4.2							  Tue Sep 25 2012						       dlaqp2.f(3)

Check Out this Related Man Page

DLAQP2(l)								 )								 DLAQP2(l)

NAME

       DLAQP2 - compute a QR factorization with column pivoting of the block A(OFFSET+1:M,1:N)

SYNOPSIS

       SUBROUTINE DLAQP2( M, N, OFFSET, A, LDA, JPVT, TAU, VN1, VN2, WORK )

	   INTEGER	  LDA, M, N, OFFSET

	   INTEGER	  JPVT( * )

	   DOUBLE	  PRECISION A( LDA, * ), TAU( * ), VN1( * ), VN2( * ), WORK( * )

PURPOSE

       DLAQP2  computes  a QR factorization with column pivoting of the block A(OFFSET+1:M,1:N). The block A(1:OFFSET,1:N) is accordingly pivoted,
       but not factorized.

ARGUMENTS

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

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

       OFFSET  (input) INTEGER
	       The number of rows of the matrix A that must be pivoted but no factorized. OFFSET >= 0.

       A       (input/output) DOUBLE PRECISION array, dimension (LDA,N)
	       On entry, the M-by-N matrix A.  On exit, the upper triangle of block A(OFFSET+1:M,1:N) is the triangular factor obtained; the  ele-
	       ments in block A(OFFSET+1:M,1:N) below the diagonal, together with the array TAU, represent the orthogonal matrix Q as a product of
	       elementary reflectors. Block A(1:OFFSET,1:N) has been accordingly pivoted, but no factorized.

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

       JPVT    (input/output) INTEGER array, dimension (N)
	       On entry, if JPVT(i) .ne. 0, the i-th column of A is permuted to the front of A*P (a leading column); if JPVT(i) = 0, the i-th col-
	       umn of A is a free column.  On exit, if JPVT(i) = k, then the i-th column of A*P was the k-th column of A.

       TAU     (output) DOUBLE PRECISION array, dimension (min(M,N))
	       The scalar factors of the elementary reflectors.

       VN1     (input/output) DOUBLE PRECISION array, dimension (N)
	       The vector with the partial column norms.

       VN2     (input/output) DOUBLE PRECISION array, dimension (N)
	       The vector with the exact column norms.

       WORK    (workspace) DOUBLE PRECISION array, dimension (N)

FURTHER DETAILS

       Based on contributions by
	 G. Quintana-Orti, Depto. de Informatica, Universidad Jaime I, Spain
	 X. Sun, Computer Science Dept., Duke University, USA

LAPACK version 3.0						   15 June 2000 							 DLAQP2(l)
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