Constant.h

// Copyright (C) 2006-2009 Anders Logg
//
// This file is part of DOLFIN.
//
// DOLFIN 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 3 of the License, or
// (at your option) any later version.
//
// DOLFIN 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 DOLFIN. If not, see <http://www.gnu.org/licenses/>.
//
// Modified by Martin Sandve Alnes, 2008.
// Modified by Garth N. Wells, 2008-2011.
 
#ifndef __CONSTANT_H
#define __CONSTANT_H
 
#include <vector>
#include <Eigen/Dense>
#include "Expression.h"
 
namespace dolfin
{
  template<typename T> class Array;
  class Mesh;

 
  class Constant : public Expression
  {
  public:

    explicit Constant(double value);

    Constant(double value0, double value1);

    Constant(double value0, double value1, double value2);

    explicit Constant(std::vector<double> values);

    Constant(std::vector<std::size_t> value_shape,
             std::vector<double> values);

    Constant(const Constant& constant);

    ~Constant();

    const Constant& operator= (const Constant& constant);

    const Constant& operator= (double constant);

    operator double() const;

    std::vector<double> values() const;
 
    //--- Implementation of Expression interface ---
 
    void eval(Array<double>& values, const Array<double>& x) const override;
 
    void eval(Eigen::Ref<Eigen::VectorXd> values,
              Eigen::Ref<const Eigen::VectorXd> x) const override;
 
    virtual std::string str(bool verbose) const override;
 
  private:
 
    // Values of constant function
    std::vector<double> _values;
 
  };
 
}
 
#endif