TESTING/LIN/dgtt02.f(3)

NAME
TESTING/LIN/dgtt02.f

SYNOPSIS

  Functions/Subroutines
subroutine dgtt02 (trans, n, nrhs, dl, d, du, x, ldx, b, ldb, resid)
DGTT02

Function/Subroutine Documentation

  subroutine dgtt02 (character trans, integer n, integer nrhs, double precision, dimension( * ) dl, double precision, dimension( * ) d, double precision, dimension( * ) du, double precision, dimension( ldx, * ) x, integer ldx, double precision, dimension( ldb, * ) b, integer ldb, double precision resid)

DGTT02

Purpose:

    !>
    !> DGTT02 computes the residual for the solution to a tridiagonal
    !> system of equations:
    !>    RESID = norm(B - op(A)*X) / (norm(op(A)) * norm(X) * EPS),
    !> where EPS is the machine epsilon.
    !> The norm used is the 1-norm.
    !>

Parameters
    TRANS

    !>          TRANS is CHARACTER
    !>          Specifies the form of the residual.
    !>          = 'N':  B - A    * X  (No transpose)
    !>          = 'T':  B - A**T * X  (Transpose)
    !>          = 'C':  B - A**H * X  (Conjugate transpose = Transpose)
    !>

    N

    !>          N is INTEGER
    !>          The order of the matrix A.  N >= 0.
    !>

    NRHS

    !>          NRHS is INTEGER
    !>          The number of right hand sides, i.e., the number of columns
    !>          of the matrices B and X.  NRHS >= 0.
    !>

    DL

    !>          DL is DOUBLE PRECISION array, dimension (N-1)
    !>          The (n-1) sub-diagonal elements of A.
    !>

    D

    !>          D is DOUBLE PRECISION array, dimension (N)
    !>          The diagonal elements of A.
    !>

    DU

    !>          DU is DOUBLE PRECISION array, dimension (N-1)
    !>          The (n-1) super-diagonal elements of A.
    !>

    X

    !>          X is DOUBLE PRECISION array, dimension (LDX,NRHS)
    !>          The computed solution vectors X.
    !>

    LDX

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

    B

    !>          B is DOUBLE PRECISION 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.  LDB >= max(1,N).
    !>

    RESID

    !>          RESID is DOUBLE PRECISION
    !>          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 123 of file dgtt02.f.

Author

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