FeasibilityPump.h

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//
//     Minotaur -- It's only 1/2 bull  
//
//     (C)opyright 2008 - 2025 The Minotaur Team.
//
#ifndef FEASIBILITYPUMP_H
#define FEASIBILITYPUMP_H
 
#include "Heuristic.h"
#include "Types.h"
 
namespace Minotaur {
  class Engine;
  class Problem;
 
  struct FeasPumpStats {
    UInt numNLPs;         
    UInt errors;          
    UInt numCycles;       
    double time;          
    double bestObjValue;  
  };
 
  class FeasibilityPump : public Heuristic {
 
  public:
 
    FeasibilityPump(EnvPtr env, ProblemPtr p, EnginePtr e);
 
    FeasibilityPump(EnvPtr env, ProblemPtr p, EnginePtr nlpe, EnginePtr
                    e);
 
    virtual ~FeasibilityPump();
 
    void solve(NodePtr node, RelaxationPtr rel, SolutionPoolPtr s_pool);
 
    void writeStats(std::ostream &out) const;
 
  protected:
 
    const static std::string me_;
 
    VarVector bins_;
 
    EnginePtr e_;
 
    EnvPtr env_;
 
    DoubleVector hashVal_;
 
    double intTol_;
 
    LoggerPtr logger_;
 
    UInt nToFlip_;
 
    ProblemPtr p_;
 
    DoubleVector random_;
 
    DoubleVector roundedSol_;
 
    FeasPumpStats* stats_;
 
    Timer* timer_;
 
    virtual void constructObj_(ProblemPtr prob, ConstSolutionPtr sol);
 
    void convertSol_(SolutionPoolPtr s_pool, ConstSolutionPtr sol); 
 
    bool cycle_(double find_value);
 
    double hash_();
 
    virtual void implementFP_(const double* x, SolutionPoolPtr s_pool);
 
    bool isFrac_(const double* x);
 
 
    void perturb_(double hash_val, UInt n_to_flip);
 
    void restoreBounds_(double* LB_copy, double* UB_copy, UInt vars);
 
    void saveBounds_(double* LB_copy, double* UB_copy, UInt vars);
 
    VarVector selectToFlip_(UInt n_to_flip);
 
    virtual bool shouldFP_();
 
  };
 
  typedef FeasibilityPump* FeasPumpPtr;
 
}
 
#endif