TESTING/LIN/dtpt01.f(3)    Library Functions Manual    TESTING/LIN/dtpt01.f(3)

NAME
       TESTING/LIN/dtpt01.f

SYNOPSIS
   Functions/Subroutines
       subroutine dtpt01 (uplo, diag, n, ap, ainvp, rcond, work, resid)
           DTPT01

Function/Subroutine Documentation
   subroutine dtpt01 (character uplo, character diag, integer n, double
       precision, dimension( * ) ap, double precision, dimension( * ) ainvp,
       double precision rcond, double precision, dimension( * ) work, double
       precision resid)
       DTPT01

       Purpose:


            DTPT01 computes the residual for a triangular matrix A times its
            inverse when A is stored in packed format:
               RESID = norm(A*AINV - I) / ( N * norm(A) * norm(AINV) * EPS ),
            where EPS is the machine epsilon.

       Parameters
           UPLO

                     UPLO is CHARACTER*1
                     Specifies whether the matrix A is upper or lower triangular.
                     = 'U':  Upper triangular
                     = 'L':  Lower triangular

           DIAG

                     DIAG is CHARACTER*1
                     Specifies whether or not the matrix A is unit triangular.
                     = 'N':  Non-unit triangular
                     = 'U':  Unit triangular

           N

                     N is INTEGER
                     The order of the matrix A.  N >= 0.

           AP

                     AP is DOUBLE PRECISION array, dimension (N*(N+1)/2)
                     The original upper or lower triangular matrix A, packed
                     columnwise in a linear array.  The j-th column of A is stored
                     in the array AP as follows:
                     if UPLO = 'U', AP((j-1)*j/2 + i) = A(i,j) for 1<=i<=j;
                     if UPLO = 'L',
                        AP((j-1)*(n-j) + j*(j+1)/2 + i-j) = A(i,j) for j<=i<=n.

           AINVP

                     AINVP is DOUBLE PRECISION array, dimension (N*(N+1)/2)
                     On entry, the (triangular) inverse of the matrix A, packed
                     columnwise in a linear array as in AP.
                     On exit, the contents of AINVP are destroyed.

           RCOND

                     RCOND is DOUBLE PRECISION
                     The reciprocal condition number of A, computed as
                     1/(norm(A) * norm(AINV)).

           WORK

                     WORK is DOUBLE PRECISION array, dimension (N)

           RESID

                     RESID is DOUBLE PRECISION
                     norm(A*AINV - I) / ( N * norm(A) * norm(AINV) * EPS )

       Author
           Univ. of Tennessee

           Univ. of California Berkeley

           Univ. of Colorado Denver

           NAG Ltd.

       Definition at line 107 of file dtpt01.f.

Author
       Generated automatically by Doxygen for LAPACK from the source code.

LAPACK                          Version 3.12.0         TESTING/LIN/dtpt01.f(3)