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DGETF2Run Method

Purpose ======= DGETF2 computes an LU factorization of a general m-by-n matrix A using partial pivoting with row interchanges. The factorization has the form A = P * L * U where P is a permutation matrix, L is lower triangular with unit diagonal elements (lower trapezoidal if m .GT. n), and U is upper triangular (upper trapezoidal if m .LT. n). This is the right-looking Level 2 BLAS version of the algorithm.

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,
	ref double[] A,
	int offset_a,
	int LDA,
	ref int[] IPIV,
	int offset_ipiv,
	ref int INFO
)
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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.
A  Double
(input/output) DOUBLE PRECISION array, dimension (LDA,N) On entry, the m by n matrix to be factored. On exit, the factors L and U from the factorization A = P*L*U; the unit diagonal elements of L are not stored.
offset_a  Int32
 
LDA  Int32
(input) INTEGER The leading dimension of the array A. LDA .GE. max(1,M).
IPIV  Int32
(output) INTEGER array, dimension (min(M,N)) The pivot indices; for 1 .LE. i .LE. min(M,N), row i of the matrix was interchanged with row IPIV(i).
offset_ipiv  Int32
 
INFO  Int32
(output) INTEGER = 0: successful exit .LT. 0: if INFO = -k, the k-th argument had an illegal value .GT. 0: if INFO = k, U(k,k) is exactly zero. The factorization has been completed, but the factor U is exactly singular, and division by zero will occur if it is used to solve a system of equations.
See Also