sget02.f - Man Page

subroutine sget02 (trans, m, n, nrhs, a, lda, x, ldx, b, ldb, rwork, resid)
SGET02

SGET02

Purpose:

 SGET02 computes the residual for a solution of a system of linear
 equations op(A)*X = B:
    RESID = norm(B - op(A)*X) / ( norm(op(A)) * norm(X) * EPS ),
 where op(A) = A or A**T, depending on TRANS, and EPS is the
 machine epsilon.
 The norm used is the 1-norm.

Parameters

TRANS

          TRANS is CHARACTER*1
          Specifies the form of the system of equations:
          = 'N':  A    * X = B  (No transpose)
          = 'T':  A**T * X = B  (Transpose)
          = 'C':  A**H * X = B  (Conjugate transpose = Transpose)

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.

NRHS

          NRHS is INTEGER
          The number of columns of B, the matrix of right hand sides.
          NRHS >= 0.

A

          A is REAL 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).

X

          X is REAL array, dimension (LDX,NRHS)
          The computed solution vectors for the system of linear
          equations.

LDX

          LDX is INTEGER
          The leading dimension of the array X.  If TRANS = 'N',
          LDX >= max(1,N); if TRANS = 'T' or 'C', LDX >= max(1,M).

B

          B is REAL array, dimension (LDB,NRHS)
          On entry, the right hand side vectors for the system of
          linear equations.
          On exit, B is overwritten with the difference B - op(A)*X.

LDB

          LDB is INTEGER
          The leading dimension of the array B.  IF TRANS = 'N',
          LDB >= max(1,M); if TRANS = 'T' or 'C', LDB >= max(1,N).

RWORK

          RWORK is REAL array, dimension (M)

RESID

          RESID is REAL
          The maximum over the number of right hand sides of
          norm(B - op(A)*X) / ( norm(op(A)) * norm(X) * EPS ).

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Definition at line 133 of file sget02.f.