!-------------------------------------------------------------------- 
!                           test cpu
!-------------------------------------------------------------------- 
Module ARRAYS
   integer, parameter           :: N=2e5
   real*8,    DIMENSION(N) :: X, Y, Z
   real*8,    parameter          :: epsilon=1.d-3, eps2 =epsilon**2
EndModule ARRAYS
!-------------------------------------------------------------------
Program TestNode
use ARRAYS
real*8 :: xx,yy,zz,Etot =0.

write(*,*) ' Required Memory(MB)=',3.*8.*N/1024.**2
CALL RANDOM_NUMBER(X)
CALL RANDOM_NUMBER(Y)
CALL RANDOM_NUMBER(Z)
      call system_clock(i1,i2)
      call cpu_time(t0)
!$OMP PARALLEL DO DEFAULT(SHARED) &
!$OMP PRIVATE(i,xx,yy,zz,j) reduction(+:Etot)
      Do i=1,N-1
         xx = X(i)
         yy = Y(i)
         zz = Z(i)
      Do j=i+1,N
         Etot = Etot + 1./sqrt((xx-X(j))**2+   &
                                             (yy-Y(j))**2+   &
                                             (zz-Z(j))**2 +eps2 )
      EndDo 
      EndDo 
 
      call cpu_time(t1)
      call system_clock(i1b,i2b)

       write (*,'(2(a,g12.4))')   ' E=',Etot/N**2, &
                                             ' cpu time=',t1-t0
       write(*,*) ' wall-clock dtime=',float(i1b-i1)/i2b

           stop
end program TestNode