NAME

TESTING/LIN/dptt01.f

SYNOPSIS

Functions/Subroutines

subroutine dptt01 (n, d, e, df, ef, work, resid)
DPTT01

Function/Subroutine Documentation

subroutine dptt01 (integer n, double precision, dimension( * ) d, double precision, dimension( * ) e, double precision, dimension( * ) df, double precision, dimension( * ) ef, double precision, dimension( * ) work, double precision resid)

DPTT01

Purpose:



 DPTT01 reconstructs a tridiagonal matrix A from its L*D*L'


 factorization and computes the residual


    norm(L*D*L' - A) / ( n * norm(A) * EPS ),


 where EPS is the machine epsilon.

Parameters



          N is INTEGER


          The order of the matrix A.



          D is DOUBLE PRECISION array, dimension (N)


          The n diagonal elements of the tridiagonal matrix A.



          E is DOUBLE PRECISION array, dimension (N-1)


          The (n-1) subdiagonal elements of the tridiagonal matrix A.



          DF is DOUBLE PRECISION array, dimension (N)


          The n diagonal elements of the factor L from the L*D*L'


          factorization of A.



          EF is DOUBLE PRECISION array, dimension (N-1)


          The (n-1) subdiagonal elements of the factor L from the


          L*D*L' factorization of A.

WORK



          WORK is DOUBLE PRECISION array, dimension (2*N)

RESID



          RESID is DOUBLE PRECISION


          norm(L*D*L' - A) / (n * norm(A) * EPS)

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Definition at line 90 of file dptt01.f.

Author

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