wrapped_functor.h

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// The libMesh Finite Element Library.
// Copyright (C) 2002-2026 Benjamin S. Kirk, John W. Peterson, Roy H. Stogner
 
// This library is free software; you can 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.
 
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// Lesser General Public License for more details.
 
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 
 
 
#ifndef LIBMESH_WRAPPED_FUNCTOR_H
#define LIBMESH_WRAPPED_FUNCTOR_H
 
// Local Includes
#include "libmesh/fem_function_base.h"
#include "libmesh/function_base.h"
#include "libmesh/int_range.h"
#include "libmesh/point.h"
#include "libmesh/wrapped_function.h"
 
// C++ includes
#include <cstddef>
#include <memory>
 
namespace libMesh
{
 
template <typename Output=Number>
class WrappedFunctor : public FEMFunctionBase<Output>
{
public:
 
  WrappedFunctor (const FunctionBase<Output> & func)
    : _func(func.clone())
  { }
 
  WrappedFunctor (const System & sys,
                  Output fptr(const Point & p,
                              const Parameters & parameters,
                              const std::string & sys_name,
                              const std::string & unknown_name) = nullptr,
                  const Parameters * parameters = nullptr,
                  unsigned int varnum=0) :
    _func(std::make_unique<WrappedFunction<Output>>(sys, fptr, parameters, varnum)) {}
 
  WrappedFunctor (const WrappedFunctor &) = delete;
  WrappedFunctor & operator= (const WrappedFunctor &) = delete;
 
  WrappedFunctor (WrappedFunctor &&) = default;
  WrappedFunctor & operator= (WrappedFunctor &&) = default;
  virtual ~WrappedFunctor () = default;
 
  virtual void init () override { _func->init(); }
 
  virtual void init_context (const FEMContext & c) override;
 
  virtual std::unique_ptr<FEMFunctionBase<Output>> clone () const override
  {
    return std::make_unique<WrappedFunctor<Output>>(*_func);
  }
 
  virtual Output operator() (const FEMContext &,
                             const Point & p,
                             const Real time = 0.) override
  { return _func->operator()(p, time); }
 
  virtual void operator() (const FEMContext &,
                           const Point & p,
                           const Real time,
                           DenseVector<Output> & output) override
  { _func->operator() (p, time, output); }
 
  virtual Output component (const FEMContext &,
                            unsigned int i,
                            const Point & p,
                            Real time=0.) override
  { return _func->component(i, p, time); }
 
protected:
 
  std::unique_ptr<FunctionBase<Output>> _func;
};
 
 
template <typename Output>
void WrappedFunctor<Output>::init_context (const FEMContext & c)
{
  // If the context was constructed with an active var subset (e.g. projector
  // projecting only selected variables), then only those FE objects are
  // guaranteed to exist.
  const std::vector<unsigned int> * active = c.active_vars();
 
  auto check_and_init = [&c](unsigned int v, unsigned short dim)
    {
      FEAbstract * fe = nullptr;
      c.get_element_fe(v, fe, dim);
      libmesh_assert_msg(fe, "FEAbstract pointer is null for variable "
                             << v << " in dimension " << dim);
      fe->get_nothing();
    };
 
  for (const auto dim : c.elem_dimensions())
    {
      if (active)
        for (const auto v : *active)
          check_and_init(v, dim);
      else
        for (const auto v : make_range(c.n_vars()))
          check_and_init(v, dim);
    }
}
 
 
} // namespace libMesh
 
#endif // LIBMESH_WRAPPED_FUNCTOR_H