combining_evaluator.h

#ifndef EVALUATORS_COMBINING_EVALUATOR_H
#define EVALUATORS_COMBINING_EVALUATOR_H
 
#include "downward/evaluator.h"
 
#include <memory>
#include <set>
#include <string>
#include <vector>
 
namespace combining_evaluator {
/*
  CombiningEvaluator is the base class for SumEvaluator and
  MaxEvaluator, which captures the common aspects of their behaviour.
*/
class CombiningEvaluator : public Evaluator {
    std::vector<std::shared_ptr<Evaluator>> subevaluators;
    bool all_dead_ends_are_reliable;
 
protected:
    virtual int combine_values(const std::vector<int>& values) = 0;
 
public:
    CombiningEvaluator(
        const std::vector<std::shared_ptr<Evaluator>>& evals,
        const std::string& description,
        utils::Verbosity verbosity);
 
    /*
      Note: dead_ends_are_reliable() is a state-independent method, so
      it only returns true if all subevaluators report dead ends reliably.
 
      Note that we could get more fine-grained information when
      considering of reliability for a given evaluated state. For
      example, if we use h1 (unreliable) and h2 (reliable) and have a
      state where h1 is finite and h2 is infinite, then we can
      *reliably* mark the state as a dead end. There is currently no
      way to exploit such state-based information, and hence we do not
      compute it.
    */
 
    virtual bool dead_ends_are_reliable() const override;
    virtual EvaluationResult
    compute_result(EvaluationContext& eval_context) override;
 
    virtual void
    get_path_dependent_evaluators(std::set<Evaluator*>& evals) override;
};
 
} // namespace combining_evaluator
 
#endif