dgetf2 - compute an LU factorization of a general m-by-n matrix A using partial pivoting with row interchanges
SUBROUTINE DGETF2( M, N, A, LDA, IPIV, INFO) INTEGER M, N, LDA, INFO INTEGER IPIV(*) DOUBLE PRECISION A(LDA,*)
SUBROUTINE DGETF2_64( M, N, A, LDA, IPIV, INFO) INTEGER*8 M, N, LDA, INFO INTEGER*8 IPIV(*) DOUBLE PRECISION A(LDA,*)
SUBROUTINE GETF2( [M], [N], A, [LDA], IPIV, [INFO]) INTEGER :: M, N, LDA, INFO INTEGER, DIMENSION(:) :: IPIV REAL(8), DIMENSION(:,:) :: A
SUBROUTINE GETF2_64( [M], [N], A, [LDA], IPIV, [INFO]) INTEGER(8) :: M, N, LDA, INFO INTEGER(8), DIMENSION(:) :: IPIV REAL(8), DIMENSION(:,:) :: A
#include <sunperf.h>
void dgetf2(int m, int n, double *a, int lda, int *ipiv, int *info);
void dgetf2_64(long m, long n, double *a, long lda, long *ipiv, long *info);
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 > n), and U is upper triangular (upper trapezoidal if m < n).
This is the right-looking Level 2 BLAS version of the algorithm.
= 0: successful exit
< 0: if INFO = -k, the k-th argument had an illegal value
> 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.