TESTING/LIN/sgbt02.f(3)

NAME
TESTING/LIN/sgbt02.f

SYNOPSIS

  Functions/Subroutines
subroutine sgbt02 (trans, m, n, kl, ku, nrhs, a, lda, x, ldx, b, ldb, rwork, resid)
SGBT02

Function/Subroutine Documentation

  subroutine sgbt02 (character trans, integer m, integer n, integer kl, integer ku, integer nrhs, real, dimension( lda, * ) a, integer lda, real, dimension( ldx, * ) x, integer ldx, real, dimension( ldb, * ) b, integer ldb, real, dimension( * ) rwork, real resid)

SGBT02

Purpose:

     SGBT02 computes the residual for a solution of a banded system of
     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.

    KL

              KL is INTEGER
              The number of subdiagonals within the band of A.  KL >= 0.

    KU

              KU is INTEGER
              The number of superdiagonals within the band of A.  KU >= 0.

    NRHS

              NRHS is INTEGER
              The number of columns of B.  NRHS >= 0.

    A

              A is REAL array, dimension (LDA,N)
              The original matrix A in band storage, stored in rows 1 to
              KL+KU+1.

    LDA

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

    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 - 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 (MAX(1,LRWORK)),
              where LRWORK >= M when TRANS = 'T' or 'C'; otherwise, RWORK
              is not referenced.

    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 147 of file sgbt02.f.

Author

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