variation.h

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/* Brush
 
copyright 2020 William La Cava
license: GNU/GPL v3
*/
#ifndef VARIATION_H
#define VARIATION_H
 
#include "../pop/population.h"
 
#include <map>
#include <optional>
 
using namespace Brush::Pop;
 
namespace Brush {
namespace Var {
 
class MutationBase {
public:
    using Iter = tree<Node>::pre_order_iterator;
 
    static auto find_spots(tree<Node>& Tree, const SearchSpace& SS,
                            const Parameters& params)
    {
        vector<float> weights(Tree.size());
 
        // by default, mutation can happen anywhere, based on node weights
        std::transform(Tree.begin(), Tree.end(), weights.begin(),
                       [&](const auto& n){ return n.get_prob_change();});
        
        // Should have same size as prog.Tree.size, even if all weights <= 0.0
        return weights;
    }
 
    static auto mutate(tree<Node>& Tree, Iter spot, const SearchSpace& SS,
                            const Parameters& params);
};
 
template<ProgramType T>
class Variation {
public:
    Variation() = default;
    
    Variation(Parameters& params, SearchSpace& ss)
        : parameters(params)
        , search_space(ss)
    {};
 
    ~Variation() {};
 
    void init(Parameters& params, SearchSpace& ss){
        this->parameters = params;
        this->search_space = ss;
    };
 
    std::optional<Individual<T>> cross(const Individual<T>& mom,
                                       const Individual<T>& dad);
 
    std::optional<Individual<T>> mutate(const Individual<T>& parent);
 
    void vary(Population<T>& pop, int island, const vector<size_t>& parents);
 
private:
    SearchSpace search_space; // The search space for the variation operator.
    Parameters parameters;    // The parameters for the variation operator
};
 
} //namespace Var
} //namespace Brush
#endif