# dgetc2.f (3) - Linux Manuals

dgetc2.f -

## SYNOPSIS

### Functions/Subroutines

subroutine dgetc2 (N, A, LDA, IPIV, JPIV, INFO)
DGETC2 computes the LU factorization with complete pivoting of the general n-by-n matrix.

## Function/Subroutine Documentation

### subroutine dgetc2 (integerN, double precision, dimension( lda, * )A, integerLDA, integer, dimension( * )IPIV, integer, dimension( * )JPIV, integerINFO)

DGETC2 computes the LU factorization with complete pivoting of the general n-by-n matrix.

Purpose:

DGETC2 computes an LU factorization with complete pivoting of the
n-by-n 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.

Parameters:

N

N is INTEGER
The order of the matrix A. N >= 0.

A

A is DOUBLE PRECISION array, dimension (LDA, N)
On entry, the n-by-n 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

LDA is INTEGER
The leading dimension of the array A.  LDA >= max(1,N).

IPIV

IPIV is INTEGER array, dimension(N).
The pivot indices; for 1 <= i <= N, row i of the
matrix has been interchanged with row IPIV(i).

JPIV

JPIV is INTEGER array, dimension(N).
The pivot indices; for 1 <= j <= N, column j of the
matrix has been interchanged with column JPIV(j).

INFO

INFO is 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.

Author:

Univ. of Tennessee

Univ. of California Berkeley

NAG Ltd.

Date:

September 2012

Contributors:

Bo Kagstrom and Peter Poromaa, Department of Computing Science, Umea University, S-901 87 Umea, Sweden.

Definition at line 112 of file dgetc2.f.

## Author

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