prescribed_assign Subroutine

  subroutine prescribed_assign(lhs, rhs)
    !* Author: Chris MacMackin
    !  Date: March 2017
    !
    ! Assigns this object to another equation of state object,
    ! allowing the definided assignment for the precalculated density
    ! field to work correctly.
    !
    class(equation_of_state), intent(out) :: lhs
    class(prescribed_eos), intent(in)     :: rhs
    select type(lhs)
    class is(prescribed_eos)
      if (allocated(lhs%density)) then
        if (.not. same_type_as(lhs%density, rhs%density)) then
          deallocate(lhs%density)
          allocate(lhs%density, mold=rhs%density)
        end if
      else
        allocate(lhs%density, mold=rhs%density)
      end if
      lhs%density = rhs%density
    class default
      error stop ("Can't assign to `equation_of_state` object of class other "// &
                  "than `prescribed_eos`.")
    end select
  end subroutine prescribed_assign