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updates to mbqi
Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com> Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner
Arie Gurfinkel
parent
80c39eb037
commit
20300bbf94
3 changed files with 237 additions and 62 deletions
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@ -1196,6 +1196,67 @@ namespace qe {
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return false;
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}
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bool operator()(model& model, app* var, app_ref_vector& vars, expr_ref_vector& lits) {
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TRACE("qe", tout << mk_pp(var, m) << "\n" << lits;);
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m_var = alloc(contains_app, m, var);
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// reduce select-store redeces based on model.
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// rw_cfg rw(m);
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// rw(lits);
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// try first to solve for var.
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if (solve_eq(model, vars, lits)) {
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return true;
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}
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app_ref_vector selects(m);
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// check that only non-select occurrences are in disequalities.
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if (!check_diseqs(lits, selects)) {
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TRACE("qe", tout << "Could not project " << mk_pp(var, m) << " for:\n" << lits << "\n";);
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return false;
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}
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// remove disequalities.
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elim_diseqs(lits);
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// Ackerman reduction on remaining select occurrences
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// either replace occurrences by model value or other node
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// that is congruent to model value.
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ackermanize_select(model, selects, vars, lits);
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TRACE("qe", tout << selects << "\n" << lits << "\n";);
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return true;
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}
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void ackermanize_select(model& model, app_ref_vector const& selects, app_ref_vector& vars, expr_ref_vector& lits) {
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expr_ref_vector vals(m), reps(m);
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expr_ref val(m);
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expr_safe_replace sub(m);
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if (selects.empty()) {
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return;
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}
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app_ref sel(m);
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for (unsigned i = 0; i < selects.size(); ++i) {
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sel = m.mk_fresh_const("sel", m.get_sort(selects[i]));
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VERIFY (model.eval(selects[i], val));
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model.register_decl(sel->get_decl(), val);
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vals.push_back(to_app(val));
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reps.push_back(val); // TODO: direct pass could handle nested selects.
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vars.push_back(sel);
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sub.insert(selects[i], val);
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}
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sub(lits);
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remove_true(lits);
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project_plugin::partition_args(model, selects, lits);
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project_plugin::partition_values(model, reps, lits);
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}
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void remove_true(expr_ref_vector& lits) {
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for (unsigned i = 0; i < lits.size(); ++i) {
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if (m.is_true(lits[i].get())) {
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@ -1216,6 +1277,80 @@ namespace qe {
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}
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}
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// check that x occurs only under selects or in disequalities.
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bool check_diseqs(expr_ref_vector const& lits, app_ref_vector& selects) {
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expr_mark mark;
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ptr_vector<app> todo;
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app* e;
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for (unsigned i = 0; i < lits.size(); ++i) {
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e = to_app(lits[i]);
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if (is_diseq_x(e)) {
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continue;
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}
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if (contains_x(e)) {
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todo.push_back(e);
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}
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}
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while (!todo.empty()) {
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e = todo.back();
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todo.pop_back();
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if (mark.is_marked(e)) {
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continue;
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}
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mark.mark(e);
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if (m_var->x() == e) {
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return false;
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}
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unsigned start = 0;
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if (a.is_select(e)) {
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if (e->get_arg(0) == m_var->x()) {
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start = 1;
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selects.push_back(e);
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}
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}
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for (unsigned i = start; i < e->get_num_args(); ++i) {
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todo.push_back(to_app(e->get_arg(i)));
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}
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}
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return true;
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}
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void elim_diseqs(expr_ref_vector& lits) {
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for (unsigned i = 0; i < lits.size(); ++i) {
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if (is_diseq_x(lits[i].get())) {
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project_plugin::erase(lits, i);
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}
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}
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}
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bool is_update_x(app* e) {
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do {
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if (m_var->x() == e) {
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return true;
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}
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if (a.is_store(e) && contains_x(e->get_arg(0))) {
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for (unsigned i = 1; i < e->get_num_args(); ++i) {
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if (contains_x(e->get_arg(i))) {
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return false;
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}
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}
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e = to_app(e->get_arg(0));
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continue;
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}
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}
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while (false);
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return false;
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}
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bool is_diseq_x(expr* e) {
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expr *f, * s, *t;
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if (m.is_not(e, f) && m.is_eq(f, s, t)) {
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if (contains_x(s) && !contains_x(t) && is_update_x(to_app(s))) return true;
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if (contains_x(t) && !contains_x(s) && is_update_x(to_app(t))) return true;
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}
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return false;
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}
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bool solve_eq(model& model, app_ref_vector& vars, expr_ref_vector& lits) {
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// find an equality to solve for.
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expr* s, *t;
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@ -1367,13 +1502,7 @@ namespace qe {
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}
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bool array_project_plugin::operator()(model& model, app* var, app_ref_vector& vars, expr_ref_vector& lits) {
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ast_manager& m = vars.get_manager();
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app_ref_vector vvars(m, 1, &var);
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expr_ref fml = mk_and(lits);
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(*this)(model, vvars, fml, vars, false);
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lits.reset();
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flatten_and(fml, lits);
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return true;
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return (*m_imp)(model, var, vars, lits);
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}
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bool array_project_plugin::solve(model& model, app_ref_vector& vars, expr_ref_vector& lits) {
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@ -1390,9 +1519,9 @@ namespace qe {
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array_project_eqs_util pe (m);
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pe (mdl, arr_vars, fml, aux_vars);
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TRACE ("qe",
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tout << "Projected array eqs: " << fml << "\n";
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tout << "Remaining array vars: " << arr_vars << "\n";
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tout << "Aux vars: " << aux_vars << "\n";
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tout << "Projected array eqs:\n" << fml << "\n";
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tout << "Remaining array vars:\n" << arr_vars;
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tout << "Aux vars:\n" << aux_vars;
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);
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// 2. reduce selects
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@ -1406,8 +1535,8 @@ namespace qe {
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ps (mdl, arr_vars, fml, aux_vars);
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TRACE ("qe",
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tout << "Projected array selects: " << fml << "\n";
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tout << "All aux vars: " << aux_vars << "\n";
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tout << "Projected array selects:\n" << fml << "\n";
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tout << "All aux vars:\n" << aux_vars;
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);
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}
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@ -77,6 +77,40 @@ expr_ref project_plugin::pick_equality(ast_manager& m, model& model, expr* t) {
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return expr_ref(nullptr, m);
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}
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void project_plugin::partition_values(model& model, expr_ref_vector const& vals, expr_ref_vector& lits) {
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ast_manager& m = vals.get_manager();
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expr_ref val(m);
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expr_ref_vector trail(m), reps(m);
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obj_map<expr, expr*> roots;
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for (unsigned i = 0; i < vals.size(); ++i) {
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expr* v = vals[i], *root;
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VERIFY (model.eval(v, val));
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if (roots.find(val, root)) {
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lits.push_back(m.mk_eq(v, root));
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}
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else {
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roots.insert(val, v);
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trail.push_back(val);
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reps.push_back(v);
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}
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}
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if (reps.size() > 1) {
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lits.push_back(mk_distinct(reps));
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}
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}
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void project_plugin::partition_args(model& model, app_ref_vector const& selects, expr_ref_vector& lits) {
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ast_manager& m = selects.get_manager();
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if (selects.empty()) return;
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unsigned num_args = selects[0]->get_decl()->get_arity();
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for (unsigned j = 1; j < num_args; ++j) {
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expr_ref_vector args(m);
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for (unsigned i = 0; i < selects.size(); ++i) {
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args.push_back(selects[i]->get_arg(j));
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}
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project_plugin::partition_values(model, args, lits);
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}
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}
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void project_plugin::erase(expr_ref_vector& lits, unsigned& i) {
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lits[i] = lits.back();
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@ -100,6 +134,7 @@ class mbp::impl {
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// parameters
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bool m_reduce_all_selects;
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bool m_native_mbp;
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bool m_dont_sub;
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void add_plugin(project_plugin* p) {
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@ -287,7 +322,8 @@ class mbp::impl {
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void operator() (app *n) {
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expr *e1, *e2;
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if (m_array.is_select (n)) {
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for (expr * arg : *n) {
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for (unsigned i = 1; i < n->get_num_args(); ++i) {
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expr * arg = n->get_arg(i);
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if (m.get_sort(arg) == m.get_sort(m_var) && arg != m_var)
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m_res.push_back (arg);
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}
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@ -340,7 +376,8 @@ class mbp::impl {
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// -- evaluate to initialize eval cache
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(void) eval (fml);
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unsigned j = 0;
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for (app * v : vars) {
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for (unsigned i = 0; i < vars.size (); ++i) {
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app* v = vars.get(i);
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if (!project_var (eval, v, fml)) {
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vars[j++] = v;
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}
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@ -350,6 +387,7 @@ class mbp::impl {
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public:
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opt::inf_eps maximize(expr_ref_vector const& fmls, model& mdl, app* t, expr_ref& ge, expr_ref& gt) {
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arith_project_plugin arith(m);
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return arith.maximize(fmls, mdl, t, ge, gt);
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@ -490,6 +528,7 @@ public:
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void updt_params(params_ref const& p) {
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m_params.append(p);
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m_reduce_all_selects = m_params.get_bool("reduce_all_selects", false);
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m_native_mbp = m_params.get_bool("native_mbp", false);
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m_dont_sub = m_params.get_bool("dont_sub", false);
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}
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@ -508,7 +547,6 @@ public:
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bool validate_model(model& model, expr_ref_vector const& fmls) {
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expr_ref val(m);
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model_evaluator eval(model);
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for (expr * f : fmls) {
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VERIFY(model.eval(f, val) && m.is_true(val));
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}
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@ -637,19 +675,26 @@ public:
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tout << "extended model:\n";
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model_pp (tout, mdl);
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tout << "Auxiliary variables of index and value sorts:\n";
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tout << vars << "\n";
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tout << vars;
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);
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}
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// project reals and ints
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if (!arith_vars.empty ()) {
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TRACE ("qe", tout << "Arith vars: " << arith_vars << "\n";);
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TRACE ("qe", tout << "Arith vars:\n" << arith_vars;);
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if (m_native_mbp) {
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expr_ref_vector fmls(m);
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flatten_and (fml, fmls);
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(*this)(true, arith_vars, mdl, fmls);
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fml = mk_and (fmls);
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SASSERT (arith_vars.empty ());
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}
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else {
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NOT_IMPLEMENTED_YET();
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// qe::arith_project (mdl, arith_vars, fml);
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}
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TRACE ("qe",
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tout << "Projected arith vars:\n" << fml << "\n";
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@ -693,6 +738,7 @@ void mbp::updt_params(params_ref const& p) {
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void mbp::get_param_descrs(param_descrs & r) {
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r.insert("reduce_all_selects", CPK_BOOL, "(default: false) reduce selects");
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r.insert("native_mbp", CPK_BOOL, "(default: false) switch between native and spacer tailored mbp");
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r.insert("dont_sub", CPK_BOOL, "(default: false) disable substitution of values for free variables");
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}
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