1
SUBROUTINE DGETRF( M, N, A, LDA, IPIV, INFO )
3
* -- LAPACK routine (version 3.0) --
4
* Univ. of Tennessee, Univ. of California Berkeley, NAG Ltd.,
5
* Courant Institute, Argonne National Lab, and Rice University
8
* -- Modified by R. Clint Whaley for ATLAS Fortran77 LAPACK interface,
11
* .. Scalar Arguments ..
12
INTEGER INFO, LDA, M, N
14
* .. Array Arguments ..
16
DOUBLE PRECISION A( LDA, * )
22
* DGETRF computes an LU factorization of a general M-by-N matrix A
23
* using partial pivoting with row interchanges.
25
* The factorization has the form
27
* where P is a permutation matrix, L is lower triangular with unit
28
* diagonal elements (lower trapezoidal if m > n), and U is upper
29
* triangular (upper trapezoidal if m < n).
35
* The number of rows of the matrix A. M >= 0.
38
* The number of columns of the matrix A. N >= 0.
40
* A (input/output) DOUBLE PRECISION array, dimension (LDA,N)
41
* On entry, the M-by-N matrix to be factored.
42
* On exit, the factors L and U from the factorization
43
* A = P*L*U; the unit diagonal elements of L are not stored.
46
* The leading dimension of the array A. LDA >= max(1,M).
48
* IPIV (output) INTEGER array, dimension (min(M,N))
49
* The pivot indices; for 1 <= i <= min(M,N), row i of the
50
* matrix was interchanged with row IPIV(i).
52
* INFO (output) INTEGER
53
* = 0: successful exit
54
* < 0: if INFO = -i, the i-th argument had an illegal value
55
* > 0: if INFO = i, U(i,i) is exactly zero. The factorization
56
* has been completed, but the factor U is exactly
57
* singular, and division by zero will occur if it is used
58
* to solve a system of equations.
60
* =====================================================================
63
* .. External Subroutines ..
64
EXTERNAL XERBLA, ATL_F77WRAP_DGETRF
66
* .. Intrinsic Functions ..
69
* .. Executable Statements ..
71
* Test the input parameters.
76
ELSE IF( N.LT.0 ) THEN
78
ELSE IF( LDA.LT.MAX( 1, M ) ) THEN
82
CALL XERBLA( 'DGETRF', -INFO )
86
CALL ATL_F77WRAP_DGETRF( M, N, A, LDA, IPIV, INFO )