simpsolver.h

多核环境下运行了可满足性分析的工具软件

/************************************************************************************[SimpSolver.h]
MiniSat -- Copyright (c) 2003-2006, Niklas Een, Niklas Sorensson

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#ifndef SimpSolver_h
#define SimpSolver_h

#include <cstdio>

#include "Queue.h"
#include "Solver.h"


namespace mira {

  class clauseDB;
}

namespace minisat {

  class SimpSolver : public Solver {
  public:
    // Constructor/Destructor:
    //
    SimpSolver();
    ~SimpSolver();
    
    // Problem specification:
    //
    Var     newVar    (bool polarity = true, bool dvar = true);
    bool    addClause (vec<Lit>& ps);
    
    // Variable mode:
    // 
    void    setFrozen (Var v, bool b); // If a variable is frozen it will not be eliminated.
    
    // Solving:
    //
    /*  bool    solve     (bool do_simp = true, bool turn_off_simp = false); */
    bool    solve     (bool do_simp = true, bool turn_off_simp = false);
    bool    eliminate (bool turn_off_elim = false);  // Perform variable elimination based simplification. 

    // Generate a (possibly simplified) DIMACS file:
    //
    void    toDimacs  (const char* file);

    // Mode of operation:
    //
    int     grow;             // Allow a variable elimination step to grow by a number of clauses (default to zero).
    bool    asymm_mode;       // Shrink clauses by asymmetric branching.
    bool    redundancy_check; // Check if a clause is already implied. Prett costly, and subsumes subsumptions :)

    // Statistics:
    //
    int     merges;
    int     asymm_lits;
    int     remembered_clauses;

    // protected:
  public:
    
    // Helper structures:
    //
    struct ElimData {
      int          order;      // 0 means not eliminated, >0 gives an index in the elimination order
      vec<Clause*> eliminated;
      ElimData() : order(0) {} };
    
    struct ElimOrderLt {
      const vec<ElimData>& elimtable;
      ElimOrderLt(const vec<ElimData>& et) : elimtable(et) {}
      bool operator()(Var x, Var y) { return elimtable[x].order > elimtable[y].order; } };

    struct ElimLt {
      const vec<int>& n_occ;
      ElimLt(const vec<int>& no) : n_occ(no) {}
      int  cost      (Var x)        const { return n_occ[toInt(Lit(x))] * n_occ[toInt(~Lit(x))]; }
      bool operator()(Var x, Var y) const { return cost(x) < cost(y); } };

    // Solver state:
    //
    int                 elimorder;
    bool                use_simplification;
    vec<ElimData>       elimtable;
    vec<char>           touched;
    vec<vec<Clause*> >  occurs;
    vec<int>            n_occ; 
    Heap<ElimLt>        elim_heap;
    Queue<Clause*>      subsumption_queue;
    vec<char>           frozen;
    int                 bwdsub_assigns;

    // Temporaries:
    //
    Clause*             bwdsub_tmpunit;

    // Main internal methods:
    //
    bool          asymm                    (Var v, Clause& c);
    bool          asymmVar                 (Var v);
    void          updateElimHeap           (Var v);
    void          cleanOcc                 (Var v);
    vec<Clause*>& getOccurs                (Var x);
    void          gatherTouchedClauses     ();
    bool          merge                    (const Clause& _ps, const Clause& _qs, Var v, vec<Lit>& out_clause);
    bool          merge                    (const Clause& _ps, const Clause& _qs, Var v);
    bool          backwardSubsumptionCheck (bool verbose = false);
    bool          eliminateVar             (Var v, bool fail = false);
    void          remember                 (Var v);
    void          extendModel              (int* Belegung);
    void          verifyModel              (int* Belegung, char* CNFFile);

    void          removeClause             (Clause& c);
    bool          strengthenClause         (Clause& c, Lit l);
    void          cleanUpClauses           ();
    bool          implied                  (const vec<Lit>& c);
    void          toDimacs                 (FILE* f, Clause& c);
    bool          isEliminated             (Var v) const;
    void          litToint                 ();

    friend bool transferClauses(mira::clauseDB * theClauseDB, minisat::SimpSolver& simp);
    friend int  clausesize(minisat::SimpSolver& simp);
  };


  //=================================================================================================
  // Implementation of inline methods:

  inline void SimpSolver::updateElimHeap(Var v) {
    if (elimtable[v].order == 0)
      elim_heap.update(v); }
 
  inline void SimpSolver::cleanOcc(Var v) {
    assert(use_simplification);
    Clause **begin = (Clause**)occurs[v];
    Clause **end = begin + occurs[v].size();
    Clause **i, **j;
    for (i = begin, j = end; i < j; i++)
      if ((*i)->mark() == 1){
	*i = *(--j);
	i--;
      }
    //occurs[v].shrink_(end - j);  // This seems slower. Why?!
    occurs[v].shrink(end - j);
  }
 
  inline vec<Clause*>& SimpSolver::getOccurs(Var x) {
    cleanOcc(x); return occurs[x]; }
  
  inline bool  SimpSolver::isEliminated (Var v) const { return v < elimtable.size() && elimtable[v].order != 0; }
  inline void  SimpSolver::setFrozen    (Var v, bool b) { frozen[v] = (char)b; if (b) { updateElimHeap(v); } }

  //=================================================================================================
  
} // end namespace minisat

#endif