cryptominisat-5.8.0/src/distillerlong.cpp

/******************************************
Copyright (c) 2016, Mate Soos

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***********************************************/

#include "distillerlong.h"
#include "clausecleaner.h"
#include "time_mem.h"
#include "solver.h"
#include "watchalgos.h"
#include "clauseallocator.h"
#include "sqlstats.h"

#include <iomanip>
using namespace CMSat;
using std::cout;
using std::endl;

#ifdef VERBOSE_DEBUG
#define VERBOSE_SUBSUME_NONEXIST
#endif

//#define VERBOSE_SUBSUME_NONEXIST

DistillerLong::DistillerLong(Solver* _solver) :
    solver(_solver)
{}

bool DistillerLong::distill(const bool red, bool fullstats)
{
    assert(solver->ok);
    numCalls++;
    Stats other;


    if (!red) {
        runStats.clear();
        if (!distill_long_cls_all(solver->longIrredCls, 1)) {
            goto end;
        }
        other = runStats;
    } else {
        runStats.clear();
        if (!distill_long_cls_all(solver->longRedCls[0], 10.0)) {
            goto end;
        }
        runStats.clear();
        if (!distill_long_cls_all(solver->longRedCls[1], solver->conf.distill_red_tier1_ratio)) {
            goto end;
        }
    }

end:
    runStats += other;
    globalStats += runStats;
    if (solver->conf.verbosity && fullstats) {
        if (solver->conf.verbosity >= 3)
            runStats.print(solver->nVars());
        else
            runStats.print_short(solver);
    }
    runStats.clear();

    return solver->okay();
}

struct ClauseSizeSorterInv
{
    ClauseSizeSorterInv(const ClauseAllocator& _cl_alloc) :
        cl_alloc(_cl_alloc)
    {}

    const ClauseAllocator& cl_alloc;

    bool operator()(const ClOffset off1, const ClOffset off2) const
    {
        const Clause* cl1 = cl_alloc.ptr(off1);
        const Clause* cl2 = cl_alloc.ptr(off2);

        return cl1->size() > cl2->size();
    }
};

bool DistillerLong::go_through_clauses(
    vector<ClOffset>& cls
) {
    bool time_out = false;
    vector<ClOffset>::iterator i, j;
    i = j = cls.begin();
    for (vector<ClOffset>::iterator end = cls.end()
        ; i != end
        ; i++
    ) {
        //Check if we are in state where we only copy offsets around
        if (time_out || !solver->ok) {
            *j++ = *i;
            continue;
        }

        //if done enough, stop doing it
        if ((int64_t)solver->propStats.bogoProps-(int64_t)oldBogoProps >= maxNumProps
            || solver->must_interrupt_asap()
        ) {
            if (solver->conf.verbosity >= 3) {
                cout
                << "c Need to finish distillation -- ran out of prop (=allocated time)"
                << endl;
            }
            runStats.timeOut++;
            time_out = true;
        }

        //Get pointer
        ClOffset offset = *i;
        ClOffset offset2;
        Clause& cl = *solver->cl_alloc.ptr(offset);
        if (cl.used_in_xor() &&
            solver->conf.force_preserve_xors
        ) {
            offset2 = offset;
            goto copy;
        }

        //Time to dereference
        maxNumProps -= 5;

        //If we already tried this clause, then move to next
        if (cl.getdistilled() || cl._xor_is_detached) {
            *j++ = *i;
            continue;
        }
        cl.set_distilled(true);
        runStats.checkedClauses++;
        assert(cl.size() > 2);

        //we will detach the clause no matter what
        maxNumProps -= solver->watches[cl[0]].size();
        maxNumProps -= solver->watches[cl[1]].size();

        maxNumProps -= cl.size();
        if (solver->satisfied_cl(cl)) {
            solver->detachClause(cl);
            solver->free_cl(&cl);
            continue;
        }

        //Try to distill clause
        offset2 = try_distill_clause_and_return_new(
            offset
            , cl.red()
            , cl.stats
        );

        copy:
        if (offset2 != CL_OFFSET_MAX) {
            *j++ = offset2;
        }
    }
    cls.resize(cls.size()- (i-j));

    return time_out;
}

bool DistillerLong::distill_long_cls_all(
    vector<ClOffset>& offs
    , double time_mult
) {
    assert(solver->ok);
    if (time_mult == 0.0) {
        return solver->okay();
    }

    if (solver->conf.verbosity >= 6) {
        cout
        << "c Doing distillation branch for long clauses"
        << endl;
    }

    double myTime = cpuTime();
    const size_t origTrailSize = solver->trail_size();

    //Time-limiting
    maxNumProps =
        solver->conf.distill_long_cls_time_limitM*1000LL*1000ULL
        *solver->conf.global_timeout_multiplier;

    if (solver->litStats.irredLits + solver->litStats.redLits <
            (500ULL*1000ULL*solver->conf.var_and_mem_out_mult)
    ) {
        maxNumProps *=2;
    }
    maxNumProps *= time_mult;
    orig_maxNumProps = maxNumProps;

    //stats setup
    oldBogoProps = solver->propStats.bogoProps;
    runStats.potentialClauses += offs.size();
    runStats.numCalled += 1;

    /*std::sort(offs.begin()
        , offs.end()
        , ClauseSizeSorterInv(solver->cl_alloc)
    );*/

    bool time_out = go_through_clauses(offs);

    const double time_used = cpuTime() - myTime;
    const double time_remain = float_div(
        maxNumProps - ((int64_t)solver->propStats.bogoProps-(int64_t)oldBogoProps),
        orig_maxNumProps);
    if (solver->conf.verbosity >= 2) {
        cout << "c [distill] long cls"
        << " tried: " << runStats.checkedClauses << "/" << offs.size()
        << " cl-short:" << runStats.numClShorten
        << " lit-r:" << runStats.numLitsRem
        << solver->conf.print_times(time_used, time_out, time_remain)
        << endl;
    }
    if (solver->sqlStats) {
        solver->sqlStats->time_passed(
            solver
            , "distill long cls"
            , time_used
            , time_out
            , time_remain
        );
    }

    //Update stats
    runStats.time_used += cpuTime() - myTime;
    runStats.zeroDepthAssigns += solver->trail_size() - origTrailSize;

    return solver->okay();
}

ClOffset DistillerLong::try_distill_clause_and_return_new(
    ClOffset offset
    , const bool red
    , const ClauseStats& stats
) {
    #ifdef DRAT_DEBUG
    if (solver->conf.verbosity >= 6) {
        cout << "Trying to distill clause:" << lits << endl;
    }
    #endif

    //Try to enqueue the literals in 'queueByBy' amounts and see if we fail
    solver->detachClause(offset, false);
    Clause& cl = *solver->cl_alloc.ptr(offset);
    (*solver->drat) << deldelay << cl << fin;

    uint32_t orig_size = cl.size();
    uint32_t i = 0;
    uint32_t j = 0;
    for (uint32_t sz = cl.size(); i < sz; i++) {
        if (solver->value(cl[i]) != l_False) {
            cl[j++] = cl[i];
        }
    }
    cl.resize(j);

    solver->new_decision_level();
    bool True_confl = false;
    PropBy confl;
    i = 0;
    j = 0;
    for (uint32_t sz = cl.size(); i < sz; i++) {
        const Lit lit = cl[i];
        lbool val = solver->value(lit);
        if (val == l_Undef) {
            solver->enqueue(~lit);
            cl[j++] = cl[i];

            maxNumProps -= 5;
            confl = solver->propagate<true>();
            if (!confl.isNULL()) {
                break;
            }
        } else if (val == l_False) {
            // skip
        } else {
            assert(val == l_True);
            cl[j++] = cl[i];
            True_confl = true;
            confl = solver->varData[cl[i].var()].reason;
            break;
        }
    }
    assert(solver->ok);
    cl.resize(j);

    //Couldn't simplify the clause
    if (j == orig_size && !True_confl && confl.isNULL()) {
        solver->cancelUntil<false, true>(0);
        solver->attachClause(cl);
        solver->drat->forget_delay();
        return offset;
    }

    #ifdef VERBOSE_DEBUG
    if (j < i && solver->conf.verbosity >= 5) {
        cout
        << "c Distillation branch effective." << endl
        << "c --> shortened cl:" << cl<< endl
        << "c --> orig size:" << orig_size << endl
        << "c --> new size:" << j << endl;
    }
    #endif

    bool lits_set = false;
    if (red && j > 1 && (!confl.isNULL() || True_confl)) {
        #ifdef VERBOSE_DEBUG
        if (solver->conf.verbosity >= 5) {
            cout
            << "c Distillation even more effective." << endl
            << "c --> orig shortened cl:" << cl << endl;
        }
        #endif
        maxNumProps -= 20;
        lits.clear();
        if (True_confl) {
            lits.push_back(cl[cl.size()-1]);
        }
        solver->simple_create_learnt_clause(confl, lits, True_confl);
        if (lits.size() < cl.size()) {
            #ifdef VERBOSE_DEBUG
            if (solver->conf.verbosity >= 5) {
                cout
                << "c --> more shortened cl:" << lits << endl;
            }
            #endif
            lits_set = true;
        }
    }
    solver->cancelUntil<false, true>(0);
    runStats.numLitsRem += orig_size - cl.size();
    runStats.numClShorten++;

    //Make new clause
    if (!lits_set) {
        lits.resize(cl.size());
        std::copy(cl.begin(), cl.end(), lits.begin());
    }
    solver->free_cl(offset);
    Clause *cl2 = solver->add_clause_int(lits, red, stats);
    (*solver->drat) << findelay;

    if (cl2 != NULL) {
        cl2->set_distilled(true);
        return solver->cl_alloc.get_offset(cl2);
    } else {
        //it became a bin/unit/zero
        return CL_OFFSET_MAX;
    }
}

DistillerLong::Stats& DistillerLong::Stats::operator+=(const Stats& other)
{
    time_used += other.time_used;
    timeOut += other.timeOut;
    zeroDepthAssigns += other.zeroDepthAssigns;
    numClShorten += other.numClShorten;
    numLitsRem += other.numLitsRem;
    checkedClauses += other.checkedClauses;
    potentialClauses += other.potentialClauses;
    numCalled += other.numCalled;

    return *this;
}

void DistillerLong::Stats::print_short(const Solver* _solver) const
{
    cout
    << "c [distill] long"
    << " useful: "<< numClShorten
    << "/" << checkedClauses << "/" << potentialClauses
    << " lits-rem: " << numLitsRem
    << " 0-depth-assigns: " << zeroDepthAssigns
    << _solver->conf.print_times(time_used, timeOut)
    << endl;
}

void DistillerLong::Stats::print(const size_t nVars) const
{
    cout << "c -------- DISTILL STATS --------" << endl;
    print_stats_line("c time"
        , time_used
        , ratio_for_stat(time_used, numCalled)
        , "per call"
    );

    print_stats_line("c timed out"
        , timeOut
        , stats_line_percent(timeOut, numCalled)
        , "% of calls"
    );

    print_stats_line("c distill/checked/potential"
        , numClShorten
        , checkedClauses
        , potentialClauses
    );

    print_stats_line("c lits-rem",
        numLitsRem
    );
    print_stats_line("c 0-depth-assigns",
        zeroDepthAssigns
        , stats_line_percent(zeroDepthAssigns, nVars)
        , "% of vars"
    );
    cout << "c -------- DISTILL STATS END --------" << endl;
}

double DistillerLong::mem_used() const
{
    double mem_used = sizeof(DistillerLong);
    mem_used += lits.size()*sizeof(Lit);
    return mem_used;
}