dsycon_rook (3) Linux Manual Page

dsycon_rook.f –

Synopsis

Functions/Subroutines

subroutine dsycon_rook (UPLO, N, A, LDA, IPIV, ANORM, RCOND, WORK, IWORK, INFO)
DSYCON_ROOK

Function/Subroutine Documentation

subroutine dsycon_rook (characterUPLO, integerN, double precision, dimension( lda, * )A, integerLDA, integer, dimension( * )IPIV, double precisionANORM, double precisionRCOND, double precision, dimension( * )WORK, integer, dimension( * )IWORK, integerINFO)

DSYCON_ROOK

Purpose:

 DSYCON_ROOK estimates the reciprocal of the condition number (in the

 1-norm) of a real symmetric matrix A using the factorization

 A = U*D*U**T or A = L*D*L**T computed by DSYTRF_ROOK.

 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

 N is INTEGER

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

A

 A is DOUBLE PRECISION array, dimension (LDA,N)

 The block diagonal matrix D and the multipliers used to

 obtain the factor U or L as computed by DSYTRF_ROOK.

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 DSYTRF_ROOK.

ANORM

 ANORM is DOUBLE PRECISION

 The 1-norm of the original matrix A.

RCOND

 RCOND is DOUBLE PRECISION

 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 DOUBLE PRECISION array, dimension (2*N)

IWORK

 IWORK is INTEGER array, dimension (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:

April 2012

Contributors:

April 2012, Igor Kozachenko, Computer Science Division, University of California, Berkeley

September 2007, Sven Hammarling, Nicholas J. Higham, Craig Lucas, School of Mathematics, University of Manchester

Definition at line 144 of file dsycon_rook.f.

Author

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