!                          Test pointers
!
Module Octs
Integer, parameter :: Np= 4,  &
                      Nocts = 300000000

Type Oct
   Real*8 :: dens(Np)
   Type(Oct), pointer :: p1,p2,p3,p4,p5,p6
End Type Oct
End Module Octs

!--------------------------
Program TestPointers
use Octs
Type(Oct), target, save :: myocts(Nocts)

print *,' memory for data, Gb = ',8.*Np*Nocts/float(1024_8**3)
Do i=1,Nocts
   myocts(i)%dens = float(i)/Nocts
   myocts(i)%p1 => myocts(mod(i,Nocts)+1)
EndDo
print *, ' ---- '
 NULLIFY(myocts(Nocts)%p1,myocts(Nocts)%p2,myocts(Nocts)%p3)
 NULLIFY(myocts(Nocts)%p4,myocts(Nocts)%p5,myocts(Nocts)%p6)

print *, ' done allocation'
Do i=1,Nocts
   myocts(i)%p1 => myocts(mod(i,Nocts)+1)
   myocts(i)%p2 => myocts(mod(i+1,Nocts)+1)
   myocts(i)%p3 => myocts(mod(i+2,Nocts)+1)
   myocts(i)%p4 => myocts(mod(i+3,Nocts)+1)
   myocts(i)%p5 => myocts(mod(i+4,Nocts)+1)
   myocts(i)%p6 => myocts(mod(i+5,Nocts)+1)
EndDo
print *, ' initilization'
Do kk =1,100
Do i=1,Nocts
   Do j=1,Np
      myocts(i)%dens(j) = myocts(i)%p1%dens(j) - myocts(i)%p2%dens(j)- myocts(i)%p6%dens(j)
   EndDo
EndDo 
print *, ' done -----',kk
EndDo
Stop

End Program TestPointers