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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

ctpcon(l)


CTPCON

CTPCON

NAME
SYNOPSIS
PURPOSE
ARGUMENTS

NAME

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

SYNOPSIS

SUBROUTINE CTPCON(

NORM, UPLO, DIAG, N, AP, RCOND, WORK, RWORK, INFO )

CHARACTER

DIAG, NORM, UPLO

INTEGER

INFO, N

REAL

RCOND

REAL

RWORK( * )

COMPLEX

AP( * ), WORK( * )

PURPOSE

CTPCON estimates the reciprocal of the condition number of a packed 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.

AP (input) COMPLEX array, dimension (N*(N+1)/2)

The upper or lower triangular matrix A, packed columnwise in a linear array. The j-th column of A is stored in the array AP as follows: if UPLO = ’U’, AP(i + (j-1)*j/2) = A(i,j) for 1<=i<=j; if UPLO = ’L’, AP(i + (j-1)*(2n-j)/2) = A(i,j) for j<=i<=n. If DIAG = ’U’, the diagonal elements of A are not referenced and are assumed to be 1.

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



ctpcon(l)