TESTING/LIN/dptt02.f(3)

NAME
TESTING/LIN/dptt02.f

SYNOPSIS

  Functions/Subroutines
subroutine dptt02 (n, nrhs, d, e, x, ldx, b, ldb, resid)
DPTT02

Function/Subroutine Documentation

  subroutine dptt02 (integer n, integer nrhs, double precision, dimension( * ) d, double precision, dimension( * ) e, double precision, dimension( ldx, * ) x, integer ldx, double precision, dimension( ldb, * ) b, integer ldb, double precision resid)

DPTT02

Purpose:

     DPTT02 computes the residual for the solution to a symmetric
     tridiagonal system of equations:
        RESID = norm(B - A*X) / (norm(A) * norm(X) * EPS),
     where EPS is the machine epsilon.

Parameters
    N

              N is INTEGER
              The order of the matrix A.

    NRHS

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

    D

              D is DOUBLE PRECISION array, dimension (N)
              The n diagonal elements of the tridiagonal matrix A.

    E

              E is DOUBLE PRECISION array, dimension (N-1)
              The (n-1) subdiagonal elements of the tridiagonal matrix A.

    X

              X is DOUBLE PRECISION array, dimension (LDX,NRHS)
              The n by nrhs matrix of 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 n by nrhs matrix of right hand side vectors B.
              On exit, B is overwritten with the difference B - A*X.

    LDB

              LDB is INTEGER
              The leading dimension of the array B.  LDB >= max(1,N).

    RESID

              RESID is DOUBLE PRECISION
              norm(B - A*X) / (norm(A) * norm(X) * EPS)

Author
    Univ. of Tennessee

    Univ. of California Berkeley

    Univ. of Colorado Denver

    NAG Ltd.

Definition at line 103 of file dptt02.f.

Author

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