dgetrf-f(3)

dgetrf.f –

Synopsis

Functions/Subroutines

subroutine dgetrf (M, N, A, LDA, IPIV, INFO)
DGETRF

Function/Subroutine Documentation

subroutine dgetrf (integerM, integerN, double precision, dimension( lda, * )A, integerLDA, integer, dimension( * )IPIV, integerINFO)

DGETRF

Purpose:

 DGETRF 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 3 BLAS version of the algorithm.

 

Parameters:

M

 M is INTEGER
 The number of rows of the matrix A. M >= 0.

N

 N is INTEGER
 The number of columns of the matrix A. N >= 0.

A

 A is 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.

LDA

 LDA is INTEGER
 The leading dimension of the array A. LDA >= max(1,M).

IPIV

 IPIV is INTEGER array, dimension (min(M,N))
 The pivot indices; for 1 <= i <= min(M,N), row i of the
 matrix was interchanged with row IPIV(i).

INFO

 INFO is INTEGER
 = 0: successful exit
 < 0: if INFO = -i, the i-th argument had an illegal value
 > 0: if INFO = i, U(i,i) 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.

 

Author:

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Date:

November 2011

Definition at line 109 of file dgetrf.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.