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Livre :
Expressions régulières,
Syntaxe et mise en oeuvre :

ISBN : 978-2-7460-9712-4
EAN : 9782746097124
(Editions ENI)

GNU/Linux	CentOS 4.8	i386
	spocon(l)

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SPOCON

NAME
SYNOPSIS
PURPOSE
ARGUMENTS

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NAME

SPOCON - estimate the reciprocal of the condition number (in the 1-norm) of a real symmetric positive definite matrix using the Cholesky factorization A = U**T*U or A = L*L**T computed by SPOTRF

SYNOPSIS

	SUBROUTINE SPOCON(		UPLO, N, A, LDA, ANORM, RCOND, WORK, IWORK, INFO )
	CHARACTER		UPLO
	INTEGER		INFO, LDA, N
	REAL		ANORM, RCOND
	INTEGER		IWORK( * )
	REAL		A( LDA, * ), WORK( * )

PURPOSE

SPOCON estimates the reciprocal of the condition number (in the 1-norm) of a real symmetric positive definite matrix using the Cholesky factorization A = U**T*U or A = L*L**T computed by SPOTRF. An estimate is obtained for norm(inv(A)), and the reciprocal of the condition number is computed as RCOND = 1 / (ANORM * norm(inv(A))).

ARGUMENTS

UPLO (input) CHARACTER*1

= ’U’: Upper triangle of A is stored;
= ’L’: Lower triangle of A is stored.

N (input) INTEGER

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

A (input) REAL array, dimension (LDA,N)

The triangular factor U or L from the Cholesky factorization A = U**T*U or A = L*L**T, as computed by SPOTRF.

LDA (input) INTEGER

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

ANORM (input) REAL

The 1-norm (or infinity-norm) of the symmetric matrix A.

RCOND (output) REAL

The reciprocal of the condition number of the matrix A, computed as RCOND = 1/(ANORM * AINVNM), where AINVNM is an estimate of the 1-norm of inv(A) computed in this routine.

WORK (workspace) REAL array, dimension (3*N)
IWORK (workspace) INTEGER array, dimension (N)
INFO (output) INTEGER

= 0: successful exit
< 0: if INFO = -i, the i-th argument had an illegal value

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spocon(l)