NAME

zgetrf - compute an LU factorization of a general M-by-N matrix A using partial pivoting with row interchanges

SYNOPSIS

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

INTEGER INFO, LDA, M, N

INTEGER IPIV( ∗ )

COMPLEX∗16 A( LDA, ∗ )

#include <sunperf.h>

void zgetrf(int m, int n, doublecomplex ∗za, int lda, int ∗ipivot, int ∗info) ;

PURPOSE

ZGETRF 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.
 

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∗16 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 = -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.

SunOS WorkShop_5.0  —  Last change: 10 Dec 1998