satSolver.h

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MiniSat -- Copyright (c) 2005, Niklas Sorensson
http://www.cs.chalmers.se/Cs/Research/FormalMethods/MiniSat/

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// Modified to compile with MS Visual Studio 6.0 by Alan Mishchenko

#ifndef ABC__sat__bsat__satSolver_h
#define ABC__sat__bsat__satSolver_h


#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>

#include "satVec.h"
#include "satClause.h"

ABC_NAMESPACE_HEADER_START

//#define USE_FLOAT_ACTIVITY

//=================================================================================================
// Public interface:

struct sat_solver_t;
typedef struct sat_solver_t sat_solver;

extern sat_solver* sat_solver_new(void);
extern void        sat_solver_delete(sat_solver* s);

extern int         sat_solver_addclause(sat_solver* s, lit* begin, lit* end);
extern int         sat_solver_clause_new(sat_solver* s, lit* begin, lit* end, int learnt);
extern int         sat_solver_simplify(sat_solver* s);
extern int         sat_solver_solve(sat_solver* s, lit* begin, lit* end, ABC_INT64_T nConfLimit, ABC_INT64_T nInsLimit, ABC_INT64_T nConfLimitGlobal, ABC_INT64_T nInsLimitGlobal);
extern void        sat_solver_restart( sat_solver* s );
extern void        sat_solver_rollback( sat_solver* s );

extern int         sat_solver_nvars(sat_solver* s);
extern int         sat_solver_nclauses(sat_solver* s);
extern int         sat_solver_nconflicts(sat_solver* s);
extern double      sat_solver_memory(sat_solver* s);
extern int         sat_solver_count_assigned(sat_solver* s);

extern void        sat_solver_setnvars(sat_solver* s,int n);
extern int         sat_solver_get_var_value(sat_solver* s, int v);


extern void        Sat_SolverWriteDimacs( sat_solver * p, char * pFileName, lit* assumptionsBegin, lit* assumptionsEnd, int incrementVars );
extern void        Sat_SolverPrintStats( FILE * pFile, sat_solver * p );
extern int *       Sat_SolverGetModel( sat_solver * p, int * pVars, int nVars );
extern void        Sat_SolverDoubleClauses( sat_solver * p, int iVar );

// trace recording
extern void        Sat_SolverTraceStart( sat_solver * pSat, char * pName );
extern void        Sat_SolverTraceStop( sat_solver * pSat );
extern void        Sat_SolverTraceWrite( sat_solver * pSat, int * pBeg, int * pEnd, int fRoot );

// clause storage
extern void        sat_solver_store_alloc( sat_solver * s );
extern void        sat_solver_store_write( sat_solver * s, char * pFileName );
extern void        sat_solver_store_free( sat_solver * s );
extern void        sat_solver_store_mark_roots( sat_solver * s );
extern void        sat_solver_store_mark_clauses_a( sat_solver * s );
extern void *      sat_solver_store_release( sat_solver * s ); 

//=================================================================================================
// Solver representation:

//struct clause_t;
//typedef struct clause_t clause;

struct varinfo_t;
typedef struct varinfo_t varinfo;

struct sat_solver_t
{
    int         size;          // nof variables
    int         cap;           // size of varmaps
    int         qhead;         // Head index of queue.
    int         qtail;         // Tail index of queue.

    // clauses
    Sat_Mem_t   Mem;
    int         hLearnts;      // the first learnt clause
    int         hBinary;       // the special binary clause
    clause *    binary;
    veci*       wlists;        // watcher lists
    veci        act_clas;      // contain clause activities

    // rollback
    int         iVarPivot;     // the pivot for variables
    int         iTrailPivot;   // the pivot for trail
    int         hProofPivot;   // the pivot for proof records

    // activities
#ifdef USE_FLOAT_ACTIVITY
    double      var_inc;       // Amount to bump next variable with.
    double      var_decay;     // INVERSE decay factor for variable activity: stores 1/decay. 
    float       cla_inc;       // Amount to bump next clause with.
    float       cla_decay;     // INVERSE decay factor for clause activity: stores 1/decay.
    double*     activity;      // A heuristic measurement of the activity of a variable.
#else
    int         var_inc;       // Amount to bump next variable with.
    int         var_inc2;      // Amount to bump next variable with.
    int         cla_inc;       // Amount to bump next clause with.
    unsigned*   activity;      // A heuristic measurement of the activity of a variable.
    unsigned*   activity2;     // backup variable activity
#endif
    char *      pFreqs;        // how many times this variable was assigned a value
    int         nVarUsed;

//    varinfo *   vi;            // variable information
    int*        levels;        //
    char*       assigns;       // Current values of variables.
    char*       polarity;      //
    char*       tags;          //
    char*       loads;         //

    int*        orderpos;      // Index in variable order.
    int*        reasons;       //
    lit*        trail;
    veci        tagged;        // (contains: var)
    veci        stack;         // (contains: var)

    veci        order;         // Variable order. (heap) (contains: var)
    veci        trail_lim;     // Separator indices for different decision levels in 'trail'. (contains: int)
//    veci        model;         // If problem is solved, this vector contains the model (contains: lbool).
    int *       model;         // If problem is solved, this vector contains the model (contains: lbool).
    veci        conf_final;    // If problem is unsatisfiable (possibly under assumptions),
                               // this vector represent the final conflict clause expressed in the assumptions.

    int         root_level;    // Level of first proper decision.
    int         simpdb_assigns;// Number of top-level assignments at last 'simplifyDB()'.
    int         simpdb_props;  // Number of propagations before next 'simplifyDB()'.
    double      random_seed;
    double      progress_estimate;
    int         verbosity;     // Verbosity level. 0=silent, 1=some progress report, 2=everything
    int         fVerbose;

    stats_t     stats;
    int         nLearntMax;    // max number of learned clauses
    int         nLearntStart;  // starting learned clause limit
    int         nLearntDelta;  // delta of learned clause limit
    int         nLearntRatio;  // ratio percentage of learned clauses
    int         nDBreduces;    // number of DB reductions

    ABC_INT64_T nConfLimit;    // external limit on the number of conflicts
    ABC_INT64_T nInsLimit;     // external limit on the number of implications
    abctime     nRuntimeLimit; // external limit on runtime

    veci        act_vars;      // variables whose activity has changed
    double*     factors;       // the activity factors
    int         nRestarts;     // the number of local restarts
    int         nCalls;        // the number of local restarts
    int         nCalls2;       // the number of local restarts
    veci        unit_lits;     // variables whose activity has changed
    veci        pivot_vars;    // pivot variables

    int         fSkipSimplify; // set to one to skip simplification of the clause database
    int         fNotUseRandom; // do not allow random decisions with a fixed probability

    int *       pGlobalVars;   // for experiments with global vars during interpolation
    // clause store
    void *      pStore;
    int         fSolved;

    // trace recording
    FILE *      pFile;
    int         nClauses;
    int         nRoots;

    veci        temp_clause;    // temporary storage for a CNF clause

    // CNF loading
    void *      pCnfMan;           // external CNF manager
    int(*pCnfFunc)(void * p, int); // external callback
};

static inline clause * clause_read( sat_solver * s, cla h )          
{ 
    return Sat_MemClauseHand( &s->Mem, h );      
}

static int sat_solver_var_value( sat_solver* s, int v )
{
    assert( v >= 0 && v < s->size );
    return (int)(s->model[v] == l_True);
}
static int sat_solver_var_literal( sat_solver* s, int v )
{
    assert( v >= 0 && v < s->size );
    return toLitCond( v, s->model[v] != l_True );
}
static void sat_solver_act_var_clear(sat_solver* s) 
{
    int i;
    for (i = 0; i < s->size; i++)
        s->activity[i] = 0;
    s->var_inc = 1;
}
static void sat_solver_compress(sat_solver* s) 
{
    if ( s->qtail != s->qhead )
    {
        int RetValue = sat_solver_simplify(s);
        assert( RetValue != 0 );
        (void) RetValue;
    }
}

static int sat_solver_final(sat_solver* s, int ** ppArray)
{
    *ppArray = s->conf_final.ptr;
    return s->conf_final.size;
}

static abctime sat_solver_set_runtime_limit(sat_solver* s, abctime Limit)
{
    abctime nRuntimeLimit = s->nRuntimeLimit;
    s->nRuntimeLimit = Limit;
    return nRuntimeLimit;
}

static int sat_solver_set_random(sat_solver* s, int fNotUseRandom)
{
    int fNotUseRandomOld = s->fNotUseRandom;
    s->fNotUseRandom = fNotUseRandom;
    return fNotUseRandomOld;
}

static inline void sat_solver_bookmark(sat_solver* s)
{
    assert( s->qhead == s->qtail );
    s->iVarPivot    = s->size;
    s->iTrailPivot  = s->qhead;
    Sat_MemBookMark( &s->Mem );
    if ( s->activity2 )
    {
        s->var_inc2 = s->var_inc;
        memcpy( s->activity2, s->activity, sizeof(unsigned) * s->iVarPivot );
    }
}
static inline void sat_solver_set_pivot_variables( sat_solver* s, int * pPivots, int nPivots )
{
    s->pivot_vars.cap = nPivots;
    s->pivot_vars.size = nPivots;
    s->pivot_vars.ptr = pPivots;
}
static inline int sat_solver_count_usedvars(sat_solver* s)
{
    int i, nVars = 0;
    for ( i = 0; i < s->size; i++ )
        if ( s->pFreqs[i] )
        {
            s->pFreqs[i] = 0;
            nVars++;
        }
    return nVars;
}

static inline int sat_solver_add_const( sat_solver * pSat, int iVar, int fCompl )
{
    lit Lits[1];
    int Cid;
    assert( iVar >= 0 );

    Lits[0] = toLitCond( iVar, fCompl );
    Cid = sat_solver_addclause( pSat, Lits, Lits + 1 );
    assert( Cid );
    return 1;
}
static inline int sat_solver_add_buffer( sat_solver * pSat, int iVarA, int iVarB, int fCompl )
{
    lit Lits[2];
    int Cid;
    assert( iVarA >= 0 && iVarB >= 0 );

    Lits[0] = toLitCond( iVarA, 0 );
    Lits[1] = toLitCond( iVarB, !fCompl );
    Cid = sat_solver_addclause( pSat, Lits, Lits + 2 );
    assert( Cid );

    Lits[0] = toLitCond( iVarA, 1 );
    Lits[1] = toLitCond( iVarB, fCompl );
    Cid = sat_solver_addclause( pSat, Lits, Lits + 2 );
    assert( Cid );
    return 2;
}
static inline int sat_solver_add_buffer_enable( sat_solver * pSat, int iVarA, int iVarB, int iVarEn, int fCompl )
{
    lit Lits[3];
    int Cid;
    assert( iVarA >= 0 && iVarB >= 0 && iVarEn >= 0 );

    Lits[0] = toLitCond( iVarA, 0 );
    Lits[1] = toLitCond( iVarB, !fCompl );
    Lits[2] = toLitCond( iVarEn, 1 );
    Cid = sat_solver_addclause( pSat, Lits, Lits + 3 );
    assert( Cid );

    Lits[0] = toLitCond( iVarA, 1 );
    Lits[1] = toLitCond( iVarB, fCompl );
    Lits[2] = toLitCond( iVarEn, 1 );
    Cid = sat_solver_addclause( pSat, Lits, Lits + 3 );
    assert( Cid );
    return 2;
}
static inline int sat_solver_add_and( sat_solver * pSat, int iVar, int iVar0, int iVar1, int fCompl0, int fCompl1, int fCompl )
{
    lit Lits[3];
    int Cid;

    Lits[0] = toLitCond( iVar, !fCompl );
    Lits[1] = toLitCond( iVar0, fCompl0 );
    Cid = sat_solver_addclause( pSat, Lits, Lits + 2 );
    assert( Cid );

    Lits[0] = toLitCond( iVar, !fCompl );
    Lits[1] = toLitCond( iVar1, fCompl1 );
    Cid = sat_solver_addclause( pSat, Lits, Lits + 2 );
    assert( Cid );

    Lits[0] = toLitCond( iVar, fCompl );
    Lits[1] = toLitCond( iVar0, !fCompl0 );
    Lits[2] = toLitCond( iVar1, !fCompl1 );
    Cid = sat_solver_addclause( pSat, Lits, Lits + 3 );
    assert( Cid );
    return 3;
}
static inline int sat_solver_add_xor( sat_solver * pSat, int iVarA, int iVarB, int iVarC, int fCompl )
{
    lit Lits[3];
    int Cid;
    assert( iVarA >= 0 && iVarB >= 0 && iVarC >= 0 );

    Lits[0] = toLitCond( iVarA, !fCompl );
    Lits[1] = toLitCond( iVarB, 1 );
    Lits[2] = toLitCond( iVarC, 1 );
    Cid = sat_solver_addclause( pSat, Lits, Lits + 3 );
    assert( Cid );

    Lits[0] = toLitCond( iVarA, !fCompl );
    Lits[1] = toLitCond( iVarB, 0 );
    Lits[2] = toLitCond( iVarC, 0 );
    Cid = sat_solver_addclause( pSat, Lits, Lits + 3 );
    assert( Cid );

    Lits[0] = toLitCond( iVarA, fCompl );
    Lits[1] = toLitCond( iVarB, 1 );
    Lits[2] = toLitCond( iVarC, 0 );
    Cid = sat_solver_addclause( pSat, Lits, Lits + 3 );
    assert( Cid );

    Lits[0] = toLitCond( iVarA, fCompl );
    Lits[1] = toLitCond( iVarB, 0 );
    Lits[2] = toLitCond( iVarC, 1 );
    Cid = sat_solver_addclause( pSat, Lits, Lits + 3 );
    assert( Cid );
    return 4;
}
static inline int sat_solver_add_mux( sat_solver * pSat, int iVarC, int iVarT, int iVarE, int iVarZ )
{
    lit Lits[3];
    int Cid;
    assert( iVarC >= 0 && iVarT >= 0 && iVarE >= 0 && iVarZ >= 0 );

    Lits[0] = toLitCond( iVarC, 1 );
    Lits[1] = toLitCond( iVarT, 1 );
    Lits[2] = toLitCond( iVarZ, 0 );
    Cid = sat_solver_addclause( pSat, Lits, Lits + 3 );
    assert( Cid );

    Lits[0] = toLitCond( iVarC, 1 );
    Lits[1] = toLitCond( iVarT, 0 );
    Lits[2] = toLitCond( iVarZ, 1 );
    Cid = sat_solver_addclause( pSat, Lits, Lits + 3 );
    assert( Cid );

    Lits[0] = toLitCond( iVarC, 0 );
    Lits[1] = toLitCond( iVarE, 1 );
    Lits[2] = toLitCond( iVarZ, 0 );
    Cid = sat_solver_addclause( pSat, Lits, Lits + 3 );
    assert( Cid );

    Lits[0] = toLitCond( iVarC, 0 );
    Lits[1] = toLitCond( iVarE, 0 );
    Lits[2] = toLitCond( iVarZ, 1 );
    Cid = sat_solver_addclause( pSat, Lits, Lits + 3 );
    assert( Cid );

    if ( iVarT == iVarE )
        return 4;

    Lits[0] = toLitCond( iVarT, 0 );
    Lits[1] = toLitCond( iVarE, 0 );
    Lits[2] = toLitCond( iVarZ, 1 );
    Cid = sat_solver_addclause( pSat, Lits, Lits + 3 );
    assert( Cid );

    Lits[0] = toLitCond( iVarT, 1 );
    Lits[1] = toLitCond( iVarE, 1 );
    Lits[2] = toLitCond( iVarZ, 0 );
    Cid = sat_solver_addclause( pSat, Lits, Lits + 3 );
    assert( Cid );
    return 6;
}
static inline int sat_solver_add_mux41( sat_solver * pSat, int iVarC0, int iVarC1, int iVarD0, int iVarD1, int iVarD2, int iVarD3, int iVarZ )
{
    lit Lits[4];
    int Cid;
    assert( iVarC0 >= 0 && iVarC1 >= 0 && iVarD0 >= 0 && iVarD1 >= 0 && iVarD2 >= 0 && iVarD3 >= 0 && iVarZ >= 0 );

    Lits[0] = toLitCond( iVarD0, 1 );
    Lits[1] = toLitCond( iVarC0, 0 );
    Lits[2] = toLitCond( iVarC1, 0 );
    Lits[3] = toLitCond( iVarZ,  0 );
    Cid = sat_solver_addclause( pSat, Lits, Lits + 4 );
    assert( Cid );

    Lits[0] = toLitCond( iVarD1, 1 );
    Lits[1] = toLitCond( iVarC0, 1 );
    Lits[2] = toLitCond( iVarC1, 0 );
    Lits[3] = toLitCond( iVarZ,  0 );
    Cid = sat_solver_addclause( pSat, Lits, Lits + 4 );
    assert( Cid );

    Lits[0] = toLitCond( iVarD2, 1 );
    Lits[1] = toLitCond( iVarC0, 0 );
    Lits[2] = toLitCond( iVarC1, 1 );
    Lits[3] = toLitCond( iVarZ,  0 );
    Cid = sat_solver_addclause( pSat, Lits, Lits + 4 );
    assert( Cid );

    Lits[0] = toLitCond( iVarD3, 1 );
    Lits[1] = toLitCond( iVarC0, 1 );
    Lits[2] = toLitCond( iVarC1, 1 );
    Lits[3] = toLitCond( iVarZ,  0 );
    Cid = sat_solver_addclause( pSat, Lits, Lits + 4 );
    assert( Cid );


    Lits[0] = toLitCond( iVarD0, 0 );
    Lits[1] = toLitCond( iVarC0, 0 );
    Lits[2] = toLitCond( iVarC1, 0 );
    Lits[3] = toLitCond( iVarZ,  1 );
    Cid = sat_solver_addclause( pSat, Lits, Lits + 4 );
    assert( Cid );

    Lits[0] = toLitCond( iVarD1, 0 );
    Lits[1] = toLitCond( iVarC0, 1 );
    Lits[2] = toLitCond( iVarC1, 0 );
    Lits[3] = toLitCond( iVarZ,  1 );
    Cid = sat_solver_addclause( pSat, Lits, Lits + 4 );
    assert( Cid );

    Lits[0] = toLitCond( iVarD2, 0 );
    Lits[1] = toLitCond( iVarC0, 0 );
    Lits[2] = toLitCond( iVarC1, 1 );
    Lits[3] = toLitCond( iVarZ,  1 );
    Cid = sat_solver_addclause( pSat, Lits, Lits + 4 );
    assert( Cid );

    Lits[0] = toLitCond( iVarD3, 0 );
    Lits[1] = toLitCond( iVarC0, 1 );
    Lits[2] = toLitCond( iVarC1, 1 );
    Lits[3] = toLitCond( iVarZ,  1 );
    Cid = sat_solver_addclause( pSat, Lits, Lits + 4 );
    assert( Cid );
    return 8;
}
static inline int sat_solver_add_xor_and( sat_solver * pSat, int iVarF, int iVarA, int iVarB, int iVarC )
{
    // F = (a (+) b) * c
    lit Lits[4];
    int Cid;
    assert( iVarF >= 0 && iVarA >= 0 && iVarB >= 0 && iVarC >= 0 );

    Lits[0] = toLitCond( iVarF, 1 );
    Lits[1] = toLitCond( iVarA, 1 );
    Lits[2] = toLitCond( iVarB, 1 );
    Cid = sat_solver_addclause( pSat, Lits, Lits + 3 );
    assert( Cid );

    Lits[0] = toLitCond( iVarF, 1 );
    Lits[1] = toLitCond( iVarA, 0 );
    Lits[2] = toLitCond( iVarB, 0 );
    Cid = sat_solver_addclause( pSat, Lits, Lits + 3 );
    assert( Cid );

    Lits[0] = toLitCond( iVarF, 1 );
    Lits[1] = toLitCond( iVarC, 0 );
    Cid = sat_solver_addclause( pSat, Lits, Lits + 2 );
    assert( Cid );

    Lits[0] = toLitCond( iVarF, 0 );
    Lits[1] = toLitCond( iVarA, 1 );
    Lits[2] = toLitCond( iVarB, 0 );
    Lits[3] = toLitCond( iVarC, 1 );
    Cid = sat_solver_addclause( pSat, Lits, Lits + 4 );
    assert( Cid );

    Lits[0] = toLitCond( iVarF, 0 );
    Lits[1] = toLitCond( iVarA, 0 );
    Lits[2] = toLitCond( iVarB, 1 );
    Lits[3] = toLitCond( iVarC, 1 );
    Cid = sat_solver_addclause( pSat, Lits, Lits + 4 );
    assert( Cid );
    return 5;
}
static inline int sat_solver_add_constraint( sat_solver * pSat, int iVar, int iVar2, int fCompl )
{
    lit Lits[2];
    int Cid;
    assert( iVar >= 0 );

    Lits[0] = toLitCond( iVar, fCompl );
    Lits[1] = toLitCond( iVar2, 0 );
    Cid = sat_solver_addclause( pSat, Lits, Lits + 2 );
    assert( Cid );

    Lits[0] = toLitCond( iVar, fCompl );
    Lits[1] = toLitCond( iVar2, 1 );
    Cid = sat_solver_addclause( pSat, Lits, Lits + 2 );
    assert( Cid );
    return 2;
}


ABC_NAMESPACE_HEADER_END

#endif