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CGETF2(1) LAPACK routine (version 3.2) CGETF2(1)

NAME

CGETF2 - computes an LU factorization of a general m-by-n matrix A using partial pivoting with row interchanges

SYNOPSIS

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

The number of rows of the matrix A. M >= 0.
The number of columns of the matrix A. N >= 0.
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.
The leading dimension of the array A. LDA >= max(1,M).
The pivot indices; for 1 <= i <= min(M,N), row i of the matrix was interchanged with row IPIV(i).
= 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.
November 2008 LAPACK routine (version 3.2)