cryptominisat 5.8.0

Rust bindings for CryptoMiniSat, a boolean satisfiability solver
/******************************************
Copyright (C) 2009-2020 Authors of CryptoMiniSat, see AUTHORS file

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The above copyright notice and this permission notice shall be included in
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
***********************************************/

#include "solutionextender.h"
#include "solver.h"
#include "varreplacer.h"
#include "occsimplifier.h"

//#define VERBOSE_DEBUG_SOLUTIONEXTENDER

using namespace CMSat;

SolutionExtender::SolutionExtender(Solver* _solver, OccSimplifier* _simplifier) :
    solver(_solver)
    , simplifier(_simplifier)
{
}

void SolutionExtender::extend()
{
    if (solver->conf.verbosity >= 10) {
        cout << "c Exteding solution -- SolutionExtender::extend()" << endl;
    }

    #ifdef SLOW_DEBUG
    for(uint32_t i = 0; i < solver->varData.size(); i++) {
        uint32_t v_inter = solver->map_outer_to_inter(i);
        if (
            //decomposed's solution has beed added already, it SHOULD be set
            //but everything else is NOT OK
            (solver->varData[v_inter].removed != Removed::none
                && solver->varData[v_inter].removed != Removed::decomposed
                && solver->varData[v_inter].removed != Removed::clashed
            )
            && solver->model[i] != l_Undef
        ) {
            cout << "ERROR: variable " << i + 1
            << " set even though it's removed: "
            << removed_type_to_string(solver->varData[v_inter].removed) << endl;
            //solver->model[i] = l_Undef;
            assert(solver->model[i] == l_Undef);
        }
    }
    #endif

    //Extend variables already set
    solver->varReplacer->extend_model_already_set();

    if (simplifier) {
        simplifier->extend_model(this);
    }

    //clause has been added with "lit, ~lit" so var must be set
    for(size_t i = 0; i < solver->undef_must_set_vars.size(); i++) {
        if (solver->undef_must_set_vars[i]
            && solver->model_value(i) == l_Undef
        ) {
            solver->model[i] = l_False;
        }
    }

    //All variables, not just those set
    solver->varReplacer->extend_model_set_undef();
}

inline bool SolutionExtender::satisfied(const vector< Lit >& lits) const
{
    for(const Lit lit: lits) {
        if (solver->model_value(lit) == l_True)
            return true;
    }

    return false;
}

//called with _outer_ variable in "blockedOn"
void SolutionExtender::dummyBlocked(const uint32_t blockedOn)
{
    #ifdef VERBOSE_DEBUG_SOLUTIONEXTENDER
    cout
    << "dummy blocked lit (outer) "
    << blockedOn + 1
    << endl;
    #endif

    #ifdef SLOW_DEBUG
    const uint32_t blockedOn_inter = solver->map_outer_to_inter(blockedOn);
    assert(solver->varData[blockedOn_inter].removed == Removed::elimed);
    #endif

    //Blocked clauses set its value already
    if (solver->model_value(blockedOn) != l_Undef)
        return;

    solver->model[blockedOn] = l_False;

    //If var is replacing something else, it MUST be set.
    if (solver->varReplacer->var_is_replacing(blockedOn)) {
        solver->varReplacer->extend_model(blockedOn);
    }
}

bool SolutionExtender::addClause(const vector<Lit>& lits, const uint32_t blockedOn)
{
    #ifdef VERBOSE_DEBUG_SOLUTIONEXTENDER
    cout
    << "outer clause: "
    << lits
    << endl;
    #endif

    #ifdef SLOW_DEBUG
    const uint32_t blocked_on_inter = solver->map_outer_to_inter(blockedOn);
    assert(solver->varData[blocked_on_inter].removed == Removed::elimed);
    assert(contains_var(lits, blockedOn));
    #endif

    //Try to extend through setting variables that have been blocked but
    //were not required to be set until now
    /*for(Lit l: lits) {
        if (solver->model_value(l) == l_Undef
            && var_has_been_blocked[l.var()]
        ) {
            solver->model[l.var()] = l.sign() ? l_False : l_True;
            solver->varReplacer->extend_model(l.var());
            return false;
        }
    }*/

    //Try to set var that hasn't been set
//     for(Lit l: lits) {
//         uint32_t v_inter = solver->map_outer_to_inter(l.var());
//         if (solver->model_value(l) == l_Undef
//             && solver->varData[v_inter].removed == Removed::none
//         ) {
//             solver->model[l.var()] = l.sign() ? l_False : l_True;
//             solver->varReplacer->extend_model(l.var());
//             return false;
//         }
//     }

    if (solver->conf.verbosity >= 10) {
        for(Lit lit: lits) {
            Lit lit_inter = solver->map_outer_to_inter(lit);
            cout
            << lit << ": " << solver->model_value(lit)
            << "(elim: " << removed_type_to_string(solver->varData[lit_inter.var()].removed) << ")"
            << ", ";
        }
        cout << "blocked on: " <<  blockedOn+1 << endl;
    }

    if (solver->model_value(blockedOn) != l_Undef) {
        cout << "ERROR: Model value for var " << blockedOn+1 << " is "
        << solver->model_value(blockedOn)
        << " but that doesn't satisfy a v-elim clause on the stack!"
        << " clause is: " << lits
        << endl;

        for(Lit l: lits) {
            uint32_t v_inter = solver->map_outer_to_inter(l.var());
            cout << "Value of " << l << " : " << solver-> model_value(l)
            << " removed: " << removed_type_to_string(solver->varData[v_inter].removed)
            << endl;
        }
    }
    assert(solver->model_value(blockedOn) == l_Undef);

    //satisfy this one clause
    Lit actual_lit = lit_Undef;
    for(Lit l: lits) {
        lbool model_value = solver-> model_value(l);
        assert(model_value != l_True);
        if (l.var() == blockedOn) {
            actual_lit = l;
        } else {
            if (model_value == l_Undef) {
            } else {
                assert(model_value == l_False);
            }
        }
    }
    assert(actual_lit != lit_Undef);
    lbool val = actual_lit.sign() ? l_False : l_True;
    solver->model[blockedOn] = val;

    if (solver->conf.verbosity >= 10) {
        cout << "Extending VELIM cls. -- setting model for var "
        << blockedOn + 1 << " to " << solver->model[blockedOn] << endl;
    }
    solver->varReplacer->extend_model(blockedOn);

    assert(satisfied(lits));

    //it's been set now
    return true;
}