dpot03.f - Man Page

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

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

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

A

          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.