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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

ctrcon(l)


CTRCON

CTRCON

NAME
SYNOPSIS
PURPOSE
ARGUMENTS

NAME

CTRCON - estimate the reciprocal of the condition number of a triangular matrix A, in either the 1-norm or the infinity-norm

SYNOPSIS

SUBROUTINE CTRCON(

NORM, UPLO, DIAG, N, A, LDA, RCOND, WORK, RWORK, INFO )

CHARACTER

DIAG, NORM, UPLO

INTEGER

INFO, LDA, N

REAL

RCOND

REAL

RWORK( * )

COMPLEX

A( LDA, * ), WORK( * )

PURPOSE

CTRCON estimates the reciprocal of the condition number of a triangular matrix A, in either the 1-norm or the infinity-norm. The norm of A is computed and an estimate is obtained for norm(inv(A)), then the reciprocal of the condition number is computed as
RCOND = 1 / ( norm(A) * norm(inv(A)) ).

ARGUMENTS

NORM (input) CHARACTER*1

Specifies whether the 1-norm condition number or the infinity-norm condition number is required:
= ’1’ or ’O’: 1-norm;
= ’I’: Infinity-norm.

UPLO (input) CHARACTER*1

= ’U’: A is upper triangular;
= ’L’: A is lower triangular.

DIAG (input) CHARACTER*1

= ’N’: A is non-unit triangular;
= ’U’: A is unit triangular.

N (input) INTEGER

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

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

The triangular matrix A. If UPLO = ’U’, the leading N-by-N upper triangular part of the array A contains the upper triangular matrix, and the strictly lower triangular part of A is not referenced. If UPLO = ’L’, the leading N-by-N lower triangular part of the array A contains the lower triangular matrix, and the strictly upper triangular part of A is not referenced. If DIAG = ’U’, the diagonal elements of A are also not referenced and are assumed to be 1.

LDA (input) INTEGER

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

RCOND (output) REAL

The reciprocal of the condition number of the matrix A, computed as RCOND = 1/(norm(A) * norm(inv(A))).

WORK (workspace) COMPLEX array, dimension (2*N)
RWORK (workspace) REAL array, dimension (N)
INFO (output) INTEGER

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



ctrcon(l)