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DLAQPSRun Method

Purpose ======= DLAQPS computes a step of QR factorization with column pivoting of a real M-by-N matrix A by using Blas-3. It tries to factorize NB columns from A starting from the row OFFSET+1, and updates all of the matrix with Blas-3 xGEMM. In some cases, due to catastrophic cancellations, it cannot factorize NB columns. Hence, the actual number of factorized columns is returned in KB. Block A(1:OFFSET,1:N) is accordingly pivoted, but not factorized.

Namespace: DotNumerics.LinearAlgebra.CSLapack
Assembly: DWSIM.MathOps.DotNumerics (in DWSIM.MathOps.DotNumerics.dll) Version: 1.0.0.0 (1.0.0.0)
Syntax
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public void Run(
	int M,
	int N,
	int OFFSET,
	int NB,
	ref int KB,
	ref double[] A,
	int offset_a,
	int LDA,
	ref int[] JPVT,
	int offset_jpvt,
	ref double[] TAU,
	int offset_tau,
	ref double[] VN1,
	int offset_vn1,
	ref double[] VN2,
	int offset_vn2,
	ref double[] AUXV,
	int offset_auxv,
	ref double[] F,
	int offset_f,
	int LDF
)
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Parameters

M  Int32
(input) INTEGER The number of rows of the matrix A. M .GE. 0.
N  Int32
(input) INTEGER The number of columns of the matrix A. N .GE. 0
OFFSET  Int32
(input) INTEGER The number of rows of A that have been factorized in previous steps.
NB  Int32
(input) INTEGER The number of columns to factorize.
KB  Int32
(output) INTEGER The number of columns actually factorized.
A  Double
(input/output) DOUBLE PRECISION array, dimension (LDA,N) On entry, the M-by-N matrix A. On exit, block A(OFFSET+1:M,1:KB) is the triangular factor obtained and block A(1:OFFSET,1:N) has been accordingly pivoted, but no factorized. The rest of the matrix, block A(OFFSET+1:M,KB+1:N) has been updated.
offset_a  Int32
 
LDA  Int32
(input) INTEGER The leading dimension of the array A. LDA .GE. max(1,M).
JPVT  Int32
(input/output) INTEGER array, dimension (N) JPVT(I) = K .LE.=.GT. Column K of the full matrix A has been permuted into position I in AP.
offset_jpvt  Int32
 
TAU  Double
(output) DOUBLE PRECISION array, dimension (KB) The scalar factors of the elementary reflectors.
offset_tau  Int32
 
VN1  Double
(input/output) DOUBLE PRECISION array, dimension (N) The vector with the partial column norms.
offset_vn1  Int32
 
VN2  Double
(input/output) DOUBLE PRECISION array, dimension (N) The vector with the exact column norms.
offset_vn2  Int32
 
AUXV  Double
(input/output) DOUBLE PRECISION array, dimension (NB) Auxiliar vector.
offset_auxv  Int32
 
F  Double
(input/output) DOUBLE PRECISION array, dimension (LDF,NB) Matrix F' = L*Y'*A.
offset_f  Int32
 
LDF  Int32
(input) INTEGER The leading dimension of the array F. LDF .GE. max(1,N).
See Also