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

INTEGER        INFO, LDA, M, N

INTEGER        IPIV( * )

COMPLEX*16     A( LDA, * )

```

#### 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.

LAPACK routine (version 3.2)               April 2011                            ZGETRF(3lapack)
```