dget04.f - Man Page

subroutine dget04 (n, nrhs, x, ldx, xact, ldxact, rcond, resid)
DGET04

DGET04

Purpose:

 DGET04 computes the difference between a computed solution and the
 true solution to a system of linear equations.

 RESID =  ( norm(X-XACT) * RCOND ) / ( norm(XACT) * EPS ),
 where RCOND is the reciprocal of the condition number and EPS is the
 machine epsilon.

Parameters

N

          N is INTEGER
          The number of rows of the matrices X and XACT.  N >= 0.

NRHS

          NRHS is INTEGER
          The number of columns of the matrices X and XACT.  NRHS >= 0.

X

          X is DOUBLE PRECISION array, dimension (LDX,NRHS)
          The computed solution vectors.  Each vector is stored as a
          column of the matrix X.

LDX

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

XACT

          XACT is DOUBLE PRECISION array, dimension( LDX, NRHS )
          The exact solution vectors.  Each vector is stored as a
          column of the matrix XACT.

LDXACT

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

RCOND

          RCOND is DOUBLE PRECISION
          The reciprocal of the condition number of the coefficient
          matrix in the system of equations.

RESID

          RESID is DOUBLE PRECISION
          The maximum over the NRHS solution vectors of
          ( norm(X-XACT) * RCOND ) / ( norm(XACT) * EPS )

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Definition at line 101 of file dget04.f.