TESTING/LIN/dgtt01.f(3)

NAME
TESTING/LIN/dgtt01.f

SYNOPSIS

  Functions/Subroutines
subroutine dgtt01 (n, dl, d, du, dlf, df, duf, du2, ipiv, work, ldwork, rwork, resid)
DGTT01

Function/Subroutine Documentation

  subroutine dgtt01 (integer n, double precision, dimension( * ) dl, double precision, dimension( * ) d, double precision, dimension( * ) du, double precision, dimension( * ) dlf, double precision, dimension( * ) df, double precision, dimension( * ) duf, double precision, dimension( * ) du2, integer, dimension( * ) ipiv, double precision, dimension( ldwork, * ) work, integer ldwork, double precision, dimension( * ) rwork, double precision resid)

DGTT01

Purpose:

    !>
    !> DGTT01 reconstructs a tridiagonal matrix A from its LU factorization
    !> and computes the residual
    !>    norm(L*U - A) / ( norm(A) * EPS ),
    !> where EPS is the machine epsilon.
    !>

Parameters
    N

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

    DLF

    !>          DLF is DOUBLE PRECISION array, dimension (N-1)
    !>          The (n-1) multipliers that define the matrix L from the
    !>          LU factorization of A.
    !>

    DF

    !>          DF is DOUBLE PRECISION array, dimension (N)
    !>          The n diagonal elements of the upper triangular matrix U from
    !>          the LU factorization of A.
    !>

    DUF

    !>          DUF is DOUBLE PRECISION array, dimension (N-1)
    !>          The (n-1) elements of the first super-diagonal of U.
    !>

    DU2

    !>          DU2 is DOUBLE PRECISION array, dimension (N-2)
    !>          The (n-2) elements of the second super-diagonal of U.
    !>

    IPIV

    !>          IPIV is INTEGER array, dimension (N)
    !>          The pivot indices; for 1 <= i <= n, row i of the matrix was
    !>          interchanged with row IPIV(i).  IPIV(i) will always be either
    !>          i or i+1; IPIV(i) = i indicates a row interchange was not
    !>          required.
    !>

    WORK

    !>          WORK is DOUBLE PRECISION array, dimension (LDWORK,N)
    !>

    LDWORK

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

    RWORK

    !>          RWORK is DOUBLE PRECISION array, dimension (N)
    !>

    RESID

    !>          RESID is DOUBLE PRECISION
    !>          The scaled residual:  norm(L*U - A) / (norm(A) * EPS)
    !>

Author
    Univ. of Tennessee

    Univ. of California Berkeley

    Univ. of Colorado Denver

    NAG Ltd.

Definition at line 132 of file dgtt01.f.

Author

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