TESTING/LIN/dppt02.f(3)    Library Functions Manual    TESTING/LIN/dppt02.f(3)

NAME
       TESTING/LIN/dppt02.f

SYNOPSIS
   Functions/Subroutines
       subroutine dppt02 (uplo, n, nrhs, a, x, ldx, b, ldb, rwork, resid)
           DPPT02

Function/Subroutine Documentation
   subroutine dppt02 (character uplo, integer n, integer nrhs, double
       precision, dimension( * ) a, double precision, dimension( ldx, * ) x,
       integer ldx, double precision, dimension( ldb, * ) b, integer ldb,
       double precision, dimension( * ) rwork, double precision resid)
       DPPT02

       Purpose:


            DPPT02 computes the residual in the solution of a symmetric system
            of linear equations  A*x = b  when packed storage is used for the
            coefficient matrix.  The ratio computed is

               RESID = norm(B - A*X) / ( norm(A) * norm(X) * EPS),

            where EPS is the machine precision.

       Parameters
           UPLO

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

           N

                     N is INTEGER
                     The number of rows and columns of the matrix A.  N >= 0.

           NRHS

                     NRHS is INTEGER
                     The number of columns of B, the matrix of right hand sides.
                     NRHS >= 0.

           A

                     A is DOUBLE PRECISION array, dimension (N*(N+1)/2)
                     The original symmetric matrix A, stored as a packed
                     triangular matrix.

           X

                     X is DOUBLE PRECISION array, dimension (LDX,NRHS)
                     The computed solution vectors for the system of linear
                     equations.

           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 right hand side vectors for the system of
                     linear equations.
                     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).

           RWORK

                     RWORK is DOUBLE PRECISION array, dimension (N)

           RESID

                     RESID is DOUBLE PRECISION
                     The maximum over the number of right hand sides of
                     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 120 of file dppt02.f.

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

LAPACK                          Version 3.12.0         TESTING/LIN/dppt02.f(3)