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RedHat 9 (Linux i386) - man page for dgetc2 (redhat section l)

DGETC2(l)					)					DGETC2(l)

NAME
       DGETC2 - compute an LU factorization with complete pivoting of the n-by-n matrix A

SYNOPSIS
       SUBROUTINE DGETC2( N, A, LDA, IPIV, JPIV, INFO )

	   INTEGER	  INFO, LDA, N

	   INTEGER	  IPIV( * ), JPIV( * )

	   DOUBLE	  PRECISION A( LDA, * )

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.

ARGUMENTS
       N       (input) INTEGER
	       The order of the matrix A. N >= 0.

       A       (input/output) 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     (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, S-901 87 Umea, Sweden.

LAPACK version 3.0			   15 June 2000 				DGETC2(l)


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