cgetc2()

subroutine cgetc2	(	integer	N,
		complex, dimension( lda, * )	A,
		integer	LDA,
		integer, dimension( * )	IPIV,
		integer, dimension( * )	JPIV,
		integer	INFO
	)

CGETC2 computes the LU factorization with complete pivoting of the general n-by-n matrix.

Download CGETC2 + dependencies [TGZ] [ZIP] [TXT]

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.

Parameters

[in]	N	N is INTEGER The order of the matrix A. N >= 0.
[in,out]	A	A is 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.
[in]	LDA	LDA is INTEGER The leading dimension of the array A. LDA >= max(1, N).
[out]	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).
[out]	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).
[out]	INFO	INFO is 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.

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Contributors:

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