incremental_function.h

// ---------------------------------------------------------------------
//
// Copyright (C) 2018 by the deal.II authors
//
// This file is part of the deal.II library.
//
// The deal.II library is free software; you can use it, redistribute
// it, and/or modify it under the terms of the GNU Lesser General
// Public License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
// The full text of the license can be found in the file LICENSE.md at
// the top level directory of deal.II.
//
// ---------------------------------------------------------------------

#ifndef dealii_incremental_function_h
#define dealii_incremental_function_h


#include <deal.II/base/function.h>
#include <deal.II/base/thread_management.h>

DEAL_II_NAMESPACE_OPEN

template <typename number>
class Vector;

namespace Functions
{
  template <int dim, typename RangeNumberType = double>
  class IncrementalFunction : public Function<dim, RangeNumberType>
  {
  public:
    static const unsigned int dimension = dim;

    using time_type = typename Function<dim, RangeNumberType>::time_type;

    IncrementalFunction(Function<dim, RangeNumberType> &base);

    virtual RangeNumberType
    value(const Point<dim> &p, const unsigned int component = 0) const override;

    virtual void
    vector_value(const Point<dim> &       p,
                 Vector<RangeNumberType> &values) const override;

    void
    set_decrement(const time_type delta_t);

  private:
    Function<dim, RangeNumberType> &base;

    time_type delta_t;

    mutable Vector<RangeNumberType> values_old;

    mutable Threads::Mutex mutex;
  };

} // namespace Functions


DEAL_II_NAMESPACE_CLOSE

#endif