Contents
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,*)
F95 INTERFACE
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
C INTERFACE
#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 algo-
rithm.
M (input) The number of rows of the matrix A. M >= 0.
N (input) The number of columns of the matrix A. N >= 0.
A (input/output)
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.
LDA (input)
The leading dimension of the array A. LDA >=
max(1,M).
IPIV (output)
The pivot indices; for 1 <= i <= min(M,N), row i
of the matrix was interchanged with row IPIV(i).
INFO (output)
= 0: successful exit
< 0: if INFO = -k, the k-th argument had an ille-
gal value
> 0: if INFO = k, U(k,k) is exactly zero. The fac-
torization 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.