
SGETC2(l) ) SGETC2(l)
NAME
SGETC2  compute an LU factorization with complete pivoting of the nbyn matrix A
SYNOPSIS
SUBROUTINE SGETC2( N, A, LDA, IPIV, JPIV, INFO )
INTEGER INFO, LDA, N
INTEGER IPIV( * ), JPIV( * )
REAL A( LDA, * )
PURPOSE
SGETC2 computes an LU factorization with complete pivoting of the nbyn matrix A. The
factorization has the form A = P * L * U * Q, where P and Q are permutation matrices, L is
lower triangular with unit diagonal elements and U is upper triangular.
This is the Level 2 BLAS algorithm.
ARGUMENTS
N (input) INTEGER
The order of the matrix A. N >= 0.
A (input/output) REAL array, dimension (LDA, N)
On entry, the nbyn matrix A to be factored. On exit, the factors L and U from
the factorization A = P*L*U*Q; the unit diagonal elements of L are not stored. If
U(k, k) appears to be less than SMIN, U(k, k) is given the value of SMIN, i.e.,
giving a nonsingular perturbed system.
LDA (input) INTEGER
The leading dimension of the array A. LDA >= max(1,N).
IPIV (output) INTEGER array, dimension(N).
The pivot indices; for 1 <= i <= N, row i of the matrix has been interchanged with
row IPIV(i).
JPIV (output) INTEGER array, dimension(N).
The pivot indices; for 1 <= j <= N, column j of the matrix has been interchanged
with column JPIV(j).
INFO (output) INTEGER
= 0: successful exit
> 0: if INFO = k, U(k, k) is likely to produce owerflow if we try to solve for x
in Ax = b. So U is perturbed to avoid the overflow.
FURTHER DETAILS
Based on contributions by
Bo Kagstrom and Peter Poromaa, Department of Computing Science,
Umea University, S901 87 Umea, Sweden.
LAPACK version 3.0 15 June 2000 SGETC2(l) 
