Population.h

//-------------------------------------------------------------------------------------------------------
// Copyright (C) Taylor Woll and panga contributors. All rights reserved.
// Licensed under the MIT license. See LICENSE.txt file in the project root for
// full license information.
//-------------------------------------------------------------------------------------------------------
 
#ifndef POPULATION_H__
#define POPULATION_H__
 
#include <vector>
 
namespace panga {
 
class BitVector;
class Genome;
class Individual;
class RandomWrapper;
 
using FitnessFunction = double (*)(Individual*, void*);
 
class Population {
 public:
  Population() = delete;
  explicit Population(const Genome& genome);
  Population(const Population& rhs) = delete;
  Population(Population&& rhs) = default;
  Population& operator=(const Population& rhs) = delete;
  ~Population() = default;
 
  size_t Size() const;
 
  void Resize(size_t size, RandomWrapper* random);
 
  void Initialize(const std::vector<BitVector>& initial_population);
 
  void InitializePartialSums();
 
  void Sort();
 
  void Replace(size_t index, const Individual& individual);
 
  const Individual& GetBestIndividual() const;
 
  const Individual& GetIndividual(size_t index) const;
 
  Individual& GetIndividualWritable(size_t index);
 
  double GetMinimumScore() const;
 
  double GetAverageScore() const;
 
  double GetScoreStandardDeviation() const;
 
  double GetPopulationDiversity() const;
 
  const Individual& UniformSelect(RandomWrapper* random) const;
 
  const Individual& RouletteWheelSelect(RandomWrapper* random) const;
 
  const Individual& TournamentSelect(size_t tournament_size,
                                     RandomWrapper* random) const;
 
  const Individual& RankSelect() const;
 
  void Evaluate(FitnessFunction fitness_function, void* user_data);
 
 private:
  const Genome& genome_;
  std::vector<Individual> individuals_;
  std::vector<double> partial_sums_;
  std::vector<size_t> sorted_indices_;
  bool is_sorted_ = false;
};
 
}  // namespace panga
 
#endif  // POPULATION_H__