Provided by: liblapack-doc_3.3.1-1_all NAME

LAPACK-3  -  computes  an  LU  factorization  of  a  general m-by-n matrix A using partial
pivoting with row interchanges

SYNOPSIS

SUBROUTINE CGETF2( M, N, A, LDA, IPIV, INFO )

INTEGER        INFO, LDA, M, N

INTEGER        IPIV( * )

COMPLEX        A( LDA, * )

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.

ARGUMENTS

M       (input) INTEGER
The number of rows of the matrix A.  M >= 0.

N       (input) INTEGER
The number of columns of the matrix A.  N >= 0.

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

IPIV    (output) 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    (output) 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.

LAPACK routine (version 3.2)               April 2011                            CGETF2(3lapack)