cgetf2.f man page

cgetf2.f —

Synopsis

Functions/Subroutines

subroutine cgetf2 (M, N, A, LDA, IPIV, INFO)
CGETF2 computes the LU factorization of a general m-by-n matrix using partial pivoting with row interchanges (unblocked algorithm).

Function/Subroutine Documentation

subroutine cgetf2 (integerM, integerN, complex, dimension( lda, * )A, integerLDA, integer, dimension( * )IPIV, integerINFO)

CGETF2 computes the LU factorization of a general m-by-n matrix using partial pivoting with row interchanges (unblocked algorithm).

Purpose:

CGETF2 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.

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 COMPLEX 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 = -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.

Author:

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Date:

September 2012

Definition at line 109 of file cgetf2.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.

Referenced By

cgetf2(3) is an alias of cgetf2.f(3).

Sat Nov 16 2013 Version 3.4.2 LAPACK