function_signature.hpp

#pragma once
#include <camp/camp.hpp>
#include "serac/numerics/functional/finite_element.hpp"
 
template <typename T>
struct FunctionSignature;
 
template <typename output_type, typename... input_types>
struct FunctionSignature<output_type(input_types...)> {
  using return_type     = output_type;                 
  using parameter_types = std::tuple<input_types...>;  
 
  static constexpr int num_args = sizeof...(input_types);
 
  static constexpr auto index_seq = camp::make_int_seq<int, num_args>{};
};
 
template <mfem::Geometry::Type geom, typename test, typename... trials>
auto trial_elements_tuple(FunctionSignature<test(trials...)>)
{
  return serac::tuple<serac::finite_element<geom, trials>...>{};
}
 
template <mfem::Geometry::Type geom, typename test, typename... trials>
auto get_test_element(FunctionSignature<test(trials...)>)
{
  return serac::finite_element<geom, test>{};
}