solid_set_Filter Subroutine

    impure subroutine solid_set_Filter(this,var,field)
      !> Filters a quantity to the Eulerian grid.
      implicit none
      class(solid_set),     intent(inout) :: this                              !! A collection of solids
      character(len=*),     intent(in)    :: var                               !! Variable to compute
      type(eulerian_obj_r), intent(inout) :: field                             !! Filtered quantity
      ! Work variables
      type(eulerian_obj_r) :: my_field
      integer :: n

      ! Initialize value to zero
      field%cell=0.0_WP

      ! Create a temporary Eulerian structure, cell centered
      call my_field%Initialize('tmp',this%block,this%parallel,0)
      do n=1,this%count

        ! Filter quantity
        call this%p(n)%Filter(var,my_field)

        ! Add up cell values
        field%cell=field%cell+my_field%cell
      end do

      ! Finalize tmp variable
      call my_field%Finalize
      return
    end subroutine solid_set_Filter