table of contents
other versions
- wheezy 3.4.1+dfsg-1+deb70u1
- jessie 3.5.0-4
- jessie-backports 3.7.0-1~bpo8+1
- testing 3.7.0-2
- unstable 3.7.0-2
slaqp2.f(3) | LAPACK | slaqp2.f(3) |
NAME¶
slaqp2.f -SYNOPSIS¶
Functions/Subroutines¶
subroutine slaqp2 (M, N, OFFSET, A, LDA, JPVT, TAU, VN1, VN2, WORK)
Function/Subroutine Documentation¶
subroutine slaqp2 (integerM, integerN, integerOFFSET, real, dimension( lda, * )A, integerLDA, integer, dimension( * )JPVT, real, dimension( * )TAU, real, dimension( * )VN1, real, dimension( * )VN2, real, dimension( * )WORK)¶
SLAQP2 Purpose:SLAQP2 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.
M
N
OFFSET
A
LDA
JPVT
TAU
VN1
VN2
WORK
Author:
M is INTEGER The number of rows of the matrix A. M >= 0.
N is INTEGER The number of columns of the matrix A. N >= 0.
OFFSET is INTEGER The number of rows of the matrix A that must be pivoted but no factorized. OFFSET >= 0.
A is REAL 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 is INTEGER The leading dimension of the array A. LDA >= max(1,M).
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 is REAL array, dimension (min(M,N)) The scalar factors of the elementary reflectors.
VN1 is REAL array, dimension (N) The vector with the partial column norms.
VN2 is REAL array, dimension (N) The vector with the exact column norms.
WORK is REAL array, dimension (N)
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Date:
November 2011
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:
Partial column norm updating strategy modified on April 2011 Z. Drmac and Z. Bujanovic, Dept. of Mathematics, University of Zagreb, Croatia.
LAPACK Working Note 176
Author¶
Generated automatically by Doxygen for LAPACK from the source code.Sun May 26 2013 | Version 3.4.1 |