evaluation_template_factory_internal.h

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// ------------------------------------------------------------------------
//
// SPDX-License-Identifier: LGPL-2.1-or-later
// Copyright (C) 2021 - 2023 by the deal.II authors
//
// This file is part of the deal.II library.
//
// Part of the source code is dual licensed under Apache-2.0 WITH
// LLVM-exception OR LGPL-2.1-or-later. Detailed license information
// governing the source code and code contributions can be found in
// LICENSE.md and CONTRIBUTING.md at the top level directory of deal.II.
//
// ------------------------------------------------------------------------
 
 
#ifndef dealii_matrix_free_evaluation_template_factory_internal_h
#define dealii_matrix_free_evaluation_template_factory_internal_h
 
 
#include <deal.II/base/config.h>
 
#ifndef FE_EVAL_FACTORY_DEGREE_MAX
#  define FE_EVAL_FACTORY_DEGREE_MAX 6
#endif
 
DEAL_II_NAMESPACE_OPEN
 
namespace internal
{
  struct FastEvaluationSupported
  {
    template <int fe_degree, int n_q_points_1d>
    static bool
    run()
    {
      return fe_degree != -1;
    }
  };
 
  template <int degree, typename EvaluatorType, typename... Args>
  bool
  instantiation_helper_run(const unsigned int given_degree,
                           const unsigned int n_q_points_1d,
                           Args &...args)
  {
    if (given_degree == degree)
      {
        if (n_q_points_1d == degree + 1)
          return EvaluatorType::template run<degree, degree + 1>(args...);
        else if (n_q_points_1d == degree + 2)
          return EvaluatorType::template run<degree, degree + 2>(args...);
        else if (n_q_points_1d == degree)
          return EvaluatorType::template run<degree, degree>(args...);
        else if (n_q_points_1d == (3 * degree) / 2 + 1)
          return EvaluatorType::template run<degree, (3 * degree) / 2 + 1>(
            args...);
        else if ((n_q_points_1d == (2 * degree)) && (degree <= 4))
          return EvaluatorType::template run<degree, (2 * degree)>(args...);
        else
          // slow path
          return EvaluatorType::template run<-1, 0>(args...);
      }
    else if (degree < FE_EVAL_FACTORY_DEGREE_MAX)
      return instantiation_helper_run<
        (degree < FE_EVAL_FACTORY_DEGREE_MAX ? degree + 1 : degree),
        EvaluatorType>(given_degree, n_q_points_1d, args...);
    else
      // slow path
      return EvaluatorType::template run<-1, 0>(args...);
  }
 
  template <int degree, typename EvaluatorType, typename... Args>
  bool
  instantiation_helper_degree_run(const unsigned int given_degree,
                                  Args &...args)
  {
    if (given_degree == degree)
      {
        return EvaluatorType::template run<degree>(args...);
      }
    else if (degree < FE_EVAL_FACTORY_DEGREE_MAX)
      return instantiation_helper_degree_run<
        (degree < FE_EVAL_FACTORY_DEGREE_MAX ? degree + 1 : degree),
        EvaluatorType>(given_degree, args...);
    else
      // slow path
      return EvaluatorType::template run<-1>(args...);
  }
 
} // end of namespace internal
 
DEAL_II_NAMESPACE_CLOSE
 
#endif