csycon-f(3)

csycon.f –

Synopsis

Functions/Subroutines

subroutine csycon (UPLO, N, A, LDA, IPIV, ANORM, RCOND, WORK, INFO)
CSYCON

Function/Subroutine Documentation

subroutine csycon (characterUPLO, integerN, complex, dimension( lda, * )A, integerLDA, integer, dimension( * )IPIV, realANORM, realRCOND, complex, dimension( * )WORK, integerINFO)

CSYCON

Purpose:

 CSYCON estimates the reciprocal of the condition number (in the
 1-norm) of a complex symmetric matrix A using the factorization
 A = U*D*U**T or A = L*D*L**T computed by CSYTRF.
 An estimate is obtained for norm(inv(A)), and the reciprocal of the
 condition number is computed as RCOND = 1 / (ANORM * norm(inv(A))).

Parameters:

UPLO

 UPLO is CHARACTER*1
 Specifies whether the details of the factorization are stored
 as an upper or lower triangular matrix.
 = 'U': Upper triangular, form is A = U*D*U**T;
 = 'L': Lower triangular, form is A = L*D*L**T.

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

 A is COMPLEX array, dimension (LDA,N)
 The block diagonal matrix D and the multipliers used to
 obtain the factor U or L as computed by CSYTRF.

LDA

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

IPIV

 IPIV is INTEGER array, dimension (N)
 Details of the interchanges and the block structure of D
 as determined by CSYTRF.

ANORM

 ANORM is REAL
 The 1-norm of the original matrix A.

RCOND

 RCOND is 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

 WORK is COMPLEX 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 125 of file csycon.f.

Author

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