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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