dget01.f - Man Page

subroutine dget01 (m, n, a, lda, afac, ldafac, ipiv, rwork, resid)
DGET01

DGET01

Purpose:

 DGET01 reconstructs a matrix A from its L*U factorization and
 computes the residual
    norm(L*U - A) / ( N * norm(A) * EPS ),
 where EPS is the machine epsilon.

Parameters

M

          M is INTEGER
          The number of rows of the matrix A.  M >= 0.

N

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

A

          A is DOUBLE PRECISION array, dimension (LDA,N)
          The original M x N matrix A.

LDA

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

AFAC

          AFAC is DOUBLE PRECISION array, dimension (LDAFAC,N)
          The factored form of the matrix A.  AFAC contains the factors
          L and U from the L*U factorization as computed by DGETRF.
          Overwritten with the reconstructed matrix, and then with the
          difference L*U - A.

LDAFAC

          LDAFAC is INTEGER
          The leading dimension of the array AFAC.  LDAFAC >= max(1,M).

IPIV

          IPIV is INTEGER array, dimension (N)
          The pivot indices from DGETRF.

RWORK

          RWORK is DOUBLE PRECISION array, dimension (M)

RESID

          RESID is DOUBLE PRECISION
          norm(L*U - A) / ( N * norm(A) * EPS )

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Definition at line 105 of file dget01.f.