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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