dpot03.f3

Usage

Functions/Subroutines

subroutine dpot03 (uplo, n, a, lda, ainv, ldainv, work, ldwork, rwork, rcond, resid)
DPOT03

Function/Subroutine Documentation

subroutine dpot03 (character uplo, integer n, double precision, dimension( lda, * ) a, integer lda, double precision, dimension( ldainv, * ) ainv, integer ldainv, double precision, dimension( ldwork, * ) work, integer ldwork, double precision, dimension( * ) rwork, double precision rcond, double precision resid)

DPOT03

Purpose:

!>
!> DPOT03 computes the residual for a symmetric matrix times its
!> inverse:
!>    norm( I - A*AINV ) / ( N * norm(A) * norm(AINV) * EPS ),
!> where EPS is the machine epsilon.
!>

Parameters

UPLO

!>          UPLO is CHARACTER*1
!>          Specifies whether the upper or lower triangular part of the
!>          symmetric matrix A is stored:
!>          = 'U':  Upper triangular
!>          = 'L':  Lower triangular
!>

!>          N is INTEGER
!>          The number of rows and columns of the matrix A.  N >= 0.
!>

!>          A is DOUBLE PRECISION array, dimension (LDA,N)
!>          The original symmetric matrix A.
!>

LDA

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

AINV

!>          AINV is DOUBLE PRECISION array, dimension (LDAINV,N)
!>          On entry, the inverse of the matrix A, stored as a symmetric
!>          matrix in the same format as A.
!>          In this version, AINV is expanded into a full matrix and
!>          multiplied by A, so the opposing triangle of AINV will be
!>          changed; i.e., if the upper triangular part of AINV is
!>          stored, the lower triangular part will be used as work space.
!>

LDAINV

!>          LDAINV is INTEGER
!>          The leading dimension of the array AINV.  LDAINV >= max(1,N).
!>

WORK

!>          WORK is DOUBLE PRECISION array, dimension (LDWORK,N)
!>

LDWORK

!>          LDWORK is INTEGER
!>          The leading dimension of the array WORK.  LDWORK >= max(1,N).
!>

RWORK

!>          RWORK is DOUBLE PRECISION array, dimension (N)
!>

RCOND

!>          RCOND is DOUBLE PRECISION
!>          The reciprocal of the condition number of A, computed as
!>          ( 1/norm(A) ) / norm(AINV).
!>

RESID

!>          RESID is DOUBLE PRECISION
!>          norm(I - A*AINV) / ( N * norm(A) * norm(AINV) * EPS )
!>

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Definition at line 123 of file dpot03.f.