module mshelix {                                # multiscale helix filter type
  use helix
  type msfilter {             
    real,    dimension( :),    pointer :: flt   # (nh) filter coefficients
    integer, dimension( :, :), pointer :: lag   # (nh,ns) filter (lags,scales)
    logical, dimension( :, :), pointer :: mis   # (nd,ns) boundary conditions
  }
contains
  subroutine msallocate( msaa, nh, ns) {
    type( msfilter)   :: msaa
    integer           :: nh, ns
    allocate( msaa%flt( nh), msaa%lag( nh, ns))
    msaa%flt = 0.;  nullify( msaa%mis)
    }
  subroutine msdeallocate( msaa) {
    type( msfilter) :: msaa
    deallocate( msaa%flt, msaa%lag)
    if( associated( msaa%mis)) deallocate( msaa%mis)
    }
  subroutine onescale( i, msaa, aa) {      # Extract single-scale filter.
    integer, intent (in) :: i
    type( filter)        :: aa
    type( msfilter)      :: msaa
    aa%flt => msaa%flt
    aa%lag => msaa%lag( :, i)
    if( associated( msaa%mis)) 
	aa%mis => msaa%mis( :, i)
    else
        nullify( aa%mis)
    }
}