WeakBrancher.h

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//
//     Minotaur -- It's only 1/2 bull
//
//     (C)opyright 2009 - 2025 The Minotaur Team.
//
 
#ifndef MINOTAURWEAKBRANCHER_H
#define MINOTAURWEAKBRANCHER_H
 
#include "Brancher.h"
 
namespace Minotaur
{
 
class Engine;
class Timer;
typedef Engine* EnginePtr;
 
struct WeakBrStats {
  UInt calls;      
  UInt nodePruned; 
  double time;     
};
// A class to select a variable for branching using weak branching.
class WeakBrancher : public Brancher
{
public:
  WeakBrancher(EnvPtr env, HandlerVector& handlers);
 
  ~WeakBrancher();
 
  // base class function.
  Branches findBranches(RelaxationPtr rel, NodePtr node, ConstSolutionPtr sol,
                        SolutionPoolPtr s_pool, BrancherStatus& br_status,
                        ModVector& mods);
 
  // base class function.
  std::string getName() const;
 
  void setProblem(ProblemPtr p);
 
  // base class function.
  void updateAfterSolve(NodePtr node, ConstSolutionPtr sol);
 
  void writeStats(std::ostream& out) const;
 
private:
  BrVarCandSet cands_;
 
  const double eTol_;
 
  BrCandVector gencands_;
 
  HandlerVector handlers_;
 
  LoggerPtr logger_;
 
  const static std::string me_;
 
  ModVector mods_;
 
  ProblemPtr p_;
 
  RelaxationPtr rel_;
 
  const double* rCost_;
 
  WeakBrStats* stats_;
 
  BrancherStatus status_;
 
  DoubleVector x_;
 
  const Timer* timer_;
 
  double computeObjChange_(DoubleVector oldLb, DoubleVector oldUb);
 
  BrCandPtr findBestCandidate_(SolutionPoolPtr s_pool);
 
  void findCandidates_(bool& should_prune);
 
  void freeCandidates_(BrCandPtr no_del);
 
  double getScore_(const double& up_score, const double& down_score);
 
  void weakBranch_(BrCandPtr cand, double& obj_up, double& obj_down,
                   SolutionPoolPtr s_pool);
 
  void writeScore_(BrCandPtr cand, double score, double change_up,
                   double change_down);
};
typedef WeakBrancher* WeakBrancherPtr;
} // namespace Minotaur
#endif