cgecon-f(3)

cgecon.f –

Synopsis

Functions/Subroutines

subroutine cgecon (NORM, N, A, LDA, ANORM, RCOND, WORK, RWORK, INFO)
CGECON

Function/Subroutine Documentation

subroutine cgecon (characterNORM, integerN, complex, dimension( lda, * )A, integerLDA, realANORM, realRCOND, complex, dimension( * )WORK, real, dimension( * )RWORK, integerINFO)

CGECON

Purpose:

 CGECON estimates the reciprocal of the condition number of a general
 complex matrix A, in either the 1-norm or the infinity-norm, using
 the LU factorization computed by CGETRF.
 An estimate is obtained for norm(inv(A)), and the reciprocal of the
 condition number is computed as
 RCOND = 1 / ( norm(A) * norm(inv(A)) ).

 

Parameters:

NORM

 NORM is 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.

N

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

A

 A is COMPLEX array, dimension (LDA,N)
 The factors L and U from the factorization A = P*L*U
 as computed by CGETRF.

LDA

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

ANORM

 ANORM is REAL
 If NORM = '1' or 'O', the 1-norm of the original matrix A.
 If NORM = 'I', the infinity-norm of the original matrix A.

RCOND

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

WORK

 WORK is COMPLEX array, dimension (2*N)

RWORK

 RWORK is REAL array, dimension (2*N)

INFO

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

 

Author:

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Date:

November 2011

Definition at line 124 of file cgecon.f.

Author

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