dgetrf.f (3) Linux Manual Page

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

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