variable.hpp

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//This file is part of Bertini 2.
//
//include/bertini2/function_tree/symbols/variable.hpp is free software: you can redistribute it and/or modify
//it under the terms of the GNU General Public License as published by
//the Free Software Foundation, either version 3 of the License, or
//(at your option) any later version.
//
//include/bertini2/function_tree/symbols/variable.hpp 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 General Public License for more details.
//
//You should have received a copy of the GNU General Public License
//along with include/bertini2/function_tree/symbols/variable.hpp.  If not, see <http://www.gnu.org/licenses/>.
//
// Copyright(C) Bertini2 Development Team
//
// See <http://www.gnu.org/licenses/> for a copy of the license,
// as well as COPYING.  Bertini2 is provided with permitted
// additional terms in the b2/licenses/ directory.
 
// include/bertini2/function_tree/symbols/variable.hpp:  Declares the class Variable.
 

#ifndef BERTINI_FUNCTION_TREE_VARIABLE_HPP
#define BERTINI_FUNCTION_TREE_VARIABLE_HPP
 
#include "bertini2/function_tree/symbols/symbol.hpp"
#include "bertini2/function_tree/symbols/differential.hpp"
 
 
namespace  bertini {
namespace node{
    class Variable : public NamedSymbol
    {
    public:
        BERTINI_DEFAULT_VISITABLE()
 
 
        
        template<typename... Ts>
        static
        std::shared_ptr<Variable> Make(Ts&& ...ts){
            return std::static_pointer_cast<Variable>(Intern(std::shared_ptr<Node>( new Variable(ts...) )));
        }
 
    private:
        Variable(std::string new_name);
 
    public:
 
 
        virtual ~Variable() = default;
 
        // variables are canonical BY NAME -- Make("x") interns to a single shared x,
        // so system1's x IS system2's x.  (Value/eval-state lives on that shared node until C2
        // moves it into a per-thread eval context.)
        std::size_t HashImpl() const override
        {
            std::size_t h = typeid(Variable).hash_code();
            HashCombine(h, std::hash<std::string>{}(name()));
            return h;
        }
        bool IsSame(Node const& other) const override
        {
            auto o = dynamic_cast<Variable const*>(&other);
            return o && name() == o->name();
        }
 

        explicit operator std::string(){return name();}
 
 

        std::shared_ptr<Node> Differentiate(std::shared_ptr<Variable> const& v = nullptr) const override;

        std::shared_ptr<Node> Subs(SubstitutionMap const& substitutions) const override;

        int Degree(std::shared_ptr<Variable> const& v = nullptr) const override;
 
 
        int Degree(VariableGroup const& vars) const override;
 
        std::vector<int> MultiDegreeImpl(VariableGroup const& vars) const override;
 
 
        bool IsHomogeneous(std::shared_ptr<Variable> const& v = nullptr) const override;

        bool IsHomogeneous(VariableGroup const& vars) const override;
 
    protected:
 
        Variable();
    private:
 
        friend class boost::serialization::access;
 
        template <typename Archive>
        void serialize(Archive& ar, const unsigned /*version*/) {
            ar & boost::serialization::base_object<NamedSymbol>(*this);
        }
 
    };
 
 
 
 
} // re: namespace node
} // re: namespace bertini
 
 
 
 
#endif