CbcCompareBase.hpp

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/* $Id: CbcCompareBase.hpp 2465 2019-01-03 19:26:52Z unxusr $ */
// Copyright (C) 2002, International Business Machines
// Corporation and others.  All Rights Reserved.
// This code is licensed under the terms of the Eclipse Public License (EPL).

#ifndef CbcCompareBase_H
#define CbcCompareBase_H

//#############################################################################
/*  These are alternative strategies for node traversal.
    They can take data etc for fine tuning

    At present the node list is stored as a heap and the "test"
    comparison function returns true if node y is better than node x.

    This is rather inflexible so if the comparison functions wants
    it can signal to use alternative criterion on a complete pass
    throgh tree.

*/
#include "CbcNode.hpp"
#include "CbcConfig.h"

class CbcModel;
class CbcTree;
class CbcCompareBase {
public:
  // Default Constructor
  CbcCompareBase()
  {
    test_ = NULL;
    threaded_ = false;
  }

  virtual bool newSolution(CbcModel *) { return (false); }

  virtual bool newSolution(CbcModel *,
    double,
    int) { return (false); }

  // This allows any method to change behavior as it is called
  // after every 1000 nodes.
  // Return true if want tree re-sorted
  virtual bool every1000Nodes(CbcModel *, int)
  {
    return false;
  }

  virtual bool fullScan() const
  {
    return false;
  }

  virtual ~CbcCompareBase() {}
  virtual void generateCpp(FILE *) {}

  // Copy constructor
  CbcCompareBase(const CbcCompareBase &rhs)
  {
    test_ = rhs.test_;
    threaded_ = rhs.threaded_;
  }

  // Assignment operator
  CbcCompareBase &operator=(const CbcCompareBase &rhs)
  {
    if (this != &rhs) {
      test_ = rhs.test_;
      threaded_ = rhs.threaded_;
    }
    return *this;
  }

  virtual CbcCompareBase *clone() const
  {
    abort();
    return NULL;
  }

  virtual bool test(CbcNode *, CbcNode *)
  {
    return true;
  }

  virtual bool alternateTest(CbcNode *x, CbcNode *y)
  {
    return test(x, y);
  }

  bool operator()(CbcNode *x, CbcNode *y)
  {
    return test(x, y);
  }
  inline bool equalityTest(CbcNode *x, CbcNode *y) const
  {
    assert(x);
    assert(y);
    if (!threaded_) {
      CbcNodeInfo *infoX = x->nodeInfo();
      assert(infoX);
      int nodeNumberX = infoX->nodeNumber();
      CbcNodeInfo *infoY = y->nodeInfo();
      assert(infoY);
      int nodeNumberY = infoY->nodeNumber();
      assert(nodeNumberX != nodeNumberY);
      return (nodeNumberX > nodeNumberY);
    } else {
      assert(x->nodeNumber() != y->nodeNumber());
      return (x->nodeNumber() > y->nodeNumber());
    }
  }
  inline void sayThreaded()
  {
    threaded_ = true;
  }

protected:
  CbcCompareBase *test_;
  // If not threaded we can use better way to break ties
  bool threaded_;
};

#endif

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