genetic_search.h

Go to the documentation of this file.

#pragma once

#include <random>

#include "tc/autotuner/parameters.h"

namespace tc {
namespace autotune {

class GeneticSearch {
 public:
  GeneticSearch(
      const TuningConfiguration& conf,
      size_t n,
      uint8_t crossOverRate,
      uint8_t mutationRate,
      size_t numberElites);

  GeneticSearch(
      const std::vector<TuningConfiguration>& confs,
      size_t n,
      uint8_t crossOverRate,
      uint8_t mutationRate,
      size_t numberElites);

  void updateParameters();

 private:
  void breed();

  TuningConfiguration crossover(
      TuningConfiguration&,
      TuningConfiguration&,
      TuningConfiguration&) const;

 public:
  static constexpr int kMutateIterations = 1000;
  static constexpr int kMinCandidatesForBreeding = 3;

  using Population = std::vector<std::unique_ptr<CandidateConfiguration>>;

  Population population;
  TuningConfiguration lastBestConf;
  const size_t kMaxPopulationSize;
  const uint8_t kCrossOverRate;
  const uint8_t kMutationRate;
  const size_t kNumberElites;

  /*
   * c++11 seeding is (apparently) not of the highest quality:
   * http://www.pcg-random.org/posts/cpp-seeding-surprises.html
   * pcg-cpp seems like a good alternative:
   * https://www.johndcook.com/blog/2017/08/14/testing-rngs-with-practrand/
   * http://www.pcg-random.org/posts/pcg-passes-practrand.html
   */
  mutable std::mt19937_64 rng;
};

} // namespace autotune
} // namespace tc