TESTING/LIN/dgtt01.f(3)    Library Functions Manual    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
       Generated automatically by Doxygen for LAPACK from the source code.

LAPACK                          Version 3.12.0         TESTING/LIN/dgtt01.f(3)