ResPart_set_UpdateLookup Subroutine

    pure subroutine ResPart_set_UpdateLookup(this)
      !> Update lookup array -- The lookup array returns
      ! the local (MPI rank) index of a centroid when
      ! given the global ID of that centroid
      implicit none
      class(ResPart_set), intent(inout) :: this                                !! Set of resolved particles
      ! Work variables
      integer :: n

      ! Allocate global lookup array
      if (.not.allocated(this%lookup)) allocate(this%lookup(this%count))
      if (size(this%lookup).ne. this%count) then
        deallocate(this%lookup)
        allocate(this%lookup(this%count))
      end if

      ! Update array
      this%lookup(:)=0
      select type (particles =>this%p)
      type is (ResPart_obj)
        do n=1,this%count_
          this%lookup(particles(n)%id)=n
        end do
      end select

      return
    end subroutine ResPart_set_UpdateLookup