---
name: "cgetc2"
section: "3lapack"
platform: "linux"
package: "liblapack-doc"
version: "3.2.1-8"
release: "Debian 6.0 (Squeeze)"
platforms: ["linux"]
url: "https://new.carta.tech/cgetc2/3lapack"
---

# cgetc2(3lapack)

computes an LU factorization, using complete pivoting, of the n-by-n matrix A

## NAME

CGETC2 - computes an LU factorization, using complete pivoting, of the n-by-n matrix A

## SYNOPSIS

- SUBROUTINE CGETC2(

  N, A, LDA, IPIV, JPIV, INFO )

- INTEGER

  INFO, LDA, N

- INTEGER

  IPIV( \* ), JPIV( \* )

- COMPLEX

  A( LDA, \* )

## PURPOSE

CGETC2 computes an LU factorization, using 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 a level 1 BLAS version of the algorithm.\

## ARGUMENTS

- N (input) INTEGER

  The order of the matrix A. N \>= 0.

- A (input/output) COMPLEX array, dimension (LDA, N)

  On entry, the n-by-n matrix 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, 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 overflow if one tries 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, S-901 87 Umea, Sweden.\