mirror of
https://github.com/Z3Prover/z3
synced 2025-04-08 10:25:18 +00:00
sls: fix bug where unsat remains empty after a literal is flipped. The new satisfiable subset should be checked
refined interface between solvers to expose fixed variables for tabu objectives
This commit is contained in:
parent
24c3cd38d1
commit
e6feb8423a
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@ -1968,6 +1968,7 @@ namespace sls {
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template<typename num_t>
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bool arith_base<num_t>::set_value(expr* e, expr* v) {
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if (!a.is_int_real(e))
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return false;
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var_t w = m_expr2var.get(e->get_id(), UINT_MAX);
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@ -1984,7 +1985,14 @@ namespace sls {
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}
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if (n == value(w))
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return true;
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return update(w, n);
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bool r = update(w, n);
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if (!r) {
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IF_VERBOSE(2,
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verbose_stream() << "set value failed " << mk_pp(e, m) << " := " << mk_pp(v, m) << "\n";
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display(verbose_stream(), w) << " := " << value(w) << "\n");
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}
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return r;
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}
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template<typename num_t>
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@ -1996,6 +2004,23 @@ namespace sls {
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return expr_ref(a.mk_numeral(m_vars[v].value().to_rational(), a.is_int(e)), m);
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}
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template<typename num_t>
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bool arith_base<num_t>::is_fixed(expr* e, expr_ref& value) {
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if (!a.is_int_real(e))
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return false;
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num_t n;
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if (is_num(e, n)) {
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value = expr_ref(a.mk_numeral(n.to_rational(), a.is_int(e)), m);
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return true;
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}
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auto v = mk_term(e);
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if (is_fixed(v)) {
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value = expr_ref(a.mk_numeral(m_vars[v].value().to_rational(), a.is_int(e)), m);
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return true;
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}
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return false;
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}
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template<typename num_t>
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bool arith_base<num_t>::is_sat() {
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invariant();
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@ -280,6 +280,7 @@ namespace sls {
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void register_term(expr* e) override;
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bool set_value(expr* e, expr* v) override;
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expr_ref get_value(expr* e) override;
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bool is_fixed(expr* e, expr_ref& value) override;
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void initialize() override;
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void propagate_literal(sat::literal lit) override;
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bool propagate() override;
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@ -64,6 +64,10 @@ namespace sls {
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WITH_FALLBACK(get_value(e));
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}
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bool arith_plugin::is_fixed(expr* e, expr_ref& value) {
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WITH_FALLBACK(is_fixed(e, value));
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}
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void arith_plugin::initialize() {
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APPLY_BOTH(initialize());
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}
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@ -32,6 +32,7 @@ namespace sls {
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~arith_plugin() override {}
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void register_term(expr* e) override;
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expr_ref get_value(expr* e) override;
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bool is_fixed(expr* e, expr_ref& value) override;
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void initialize() override;
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void propagate_literal(sat::literal lit) override;
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bool propagate() override;
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@ -172,6 +172,7 @@ namespace sls {
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}
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void context::propagate_boolean_assignment() {
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start_propagation:
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reinit_relevant();
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for (auto p : m_plugins)
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@ -180,9 +181,12 @@ namespace sls {
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for (sat::literal lit : root_literals())
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propagate_literal(lit);
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if (m_new_constraint)
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return;
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if (any_of(root_literals(), [&](sat::literal lit) { return !is_true(lit); })) {
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if (unsat().empty())
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goto start_propagation;
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return;
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}
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while (!m_new_constraint && m.inc() && (!m_repair_up.empty() || !m_repair_down.empty())) {
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while (!m_repair_down.empty() && !m_new_constraint && m.inc()) {
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@ -258,9 +262,6 @@ namespace sls {
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auto p = m_plugins.get(fid, nullptr);
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if (p)
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p->propagate_literal(lit);
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if (!is_true(lit)) {
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m_new_constraint = true;
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}
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}
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bool context::is_true(expr* e) {
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@ -291,6 +292,14 @@ namespace sls {
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bool context::set_value(expr * e, expr * v) {
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return any_of(m_plugins, [&](auto p) { return p && p->set_value(e, v); });
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}
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bool context::is_fixed(expr* e, expr_ref& value) {
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if (m.is_value(e)) {
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value = e;
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return true;
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}
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return any_of(m_plugins, [&](auto p) { return p && p->is_fixed(e, value); });
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}
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bool context::is_relevant(expr* e) {
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unsigned id = e->get_id();
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@ -317,6 +326,7 @@ namespace sls {
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m_constraint_trail.push_back(e);
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add_clause(e);
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m_new_constraint = true;
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verbose_stream() << "add constraint\n";
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++m_stats.m_num_constraints;
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}
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@ -42,6 +42,7 @@ namespace sls {
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virtual family_id fid() { return m_fid; }
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virtual void register_term(expr* e) = 0;
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virtual expr_ref get_value(expr* e) = 0;
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virtual bool is_fixed(expr* e, expr_ref& value) { return false; }
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virtual void initialize() = 0;
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virtual void start_propagation() {};
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virtual bool propagate() = 0;
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@ -192,6 +193,7 @@ namespace sls {
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// Between plugin solvers
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expr_ref get_value(expr* e);
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bool is_fixed(expr* v, expr_ref& value);
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bool set_value(expr* e, expr* v);
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void new_value_eh(expr* e);
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bool is_true(expr* e);
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@ -63,7 +63,7 @@ Alternate to lookahead strategy:
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- create a priority buffer array of vector<ptr_vector<expr>> based on depth.
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- walk from lowest depth up. Reset each inner buffer when processed. Parents always
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have higher depth.
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- calculate repair/break score when hitting a predicate based on bval1.
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- calculate repair/break depth when hitting a predicate based on bval1.
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- strval1 and bval1 are modified by
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- use a global timestamp.
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- label each eval subterm by a timestamp that gets set.
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@ -145,9 +145,26 @@ namespace sls {
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auto ve = ctx.get_value(e);
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if (a.is_numeral(ve, r) && r == sx.length())
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continue;
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update(e, rational(sx.length()));
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// set e to length of x or
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// set x to a string of length e
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if (r == 0 || sx.length() == 0) {
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verbose_stream() << "todo-create lemma: len(x) = 0 <=> x = \"\"\n";
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// create a lemma: len(x) = 0 => x = ""
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}
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if (ctx.rand(2) == 0 && update(e, rational(sx.length())))
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return false;
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if (r < sx.length() && update(x, sx.extract(0, r.get_unsigned())))
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return false;
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if (update(e, rational(sx.length())))
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return false;
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if (r > sx.length() && update(x, sx + zstring(m_chars[ctx.rand(m_chars.size())])))
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return false;
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verbose_stream() << mk_pp(x, m) << " = " << sx << " " << ve << "\n";
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NOT_IMPLEMENTED_YET();
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return false;
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}
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if ((seq.str.is_index(e, x, y, z) || seq.str.is_index(e, x, y)) && seq.is_string(x->get_sort())) {
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auto sx = strval0(x);
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auto sy = strval0(y);
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@ -603,21 +620,32 @@ namespace sls {
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auto const& R = rhs(eq);
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unsigned i = 0, j = 0; // position into current string
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unsigned ni = 0, nj = 0; // current string in concatenation
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double depth = 1.0; // priority of update. Doubled when depth of equal strings are increased.
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double score = 1.0; // priority of update. Doubled when score of equal strings are increased.
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IF_VERBOSE(4,
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verbose_stream() << "unify: \"" << strval0(eq->get_arg(0)) << "\" == \"" << strval0(eq->get_arg(1)) << "\"\n";
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for (auto x : L) verbose_stream() << mk_pp(x, m) << " ";
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verbose_stream() << " == ";
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for (auto x : R) verbose_stream() << mk_pp(x, m) << " ";
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verbose_stream() << "\n";
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for (auto x : L) verbose_stream() << "\"" << strval0(x) << "\" ";
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verbose_stream() << " == ";
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for (auto x : R) verbose_stream() << "\"" << strval0(x) << "\" ";
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verbose_stream() << "\n";
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);
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while (ni < L.size() && nj < R.size()) {
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auto const& xi = L[ni];
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auto const& yj = R[nj];
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auto const& vi = strval0(xi);
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auto const& vj = strval0(yj);
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IF_VERBOSE(4,
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verbose_stream() << "unify: \"" << vi << "\" = \"" << vj << "\" incides " << i << " " << j << "\n";
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verbose_stream() << vi.length() << " " << vj.length() << "\n");
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if (vi.length() == i && vj.length() == j) {
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depth *= 2;
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score *= 2;
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if (nj + 1 < R.size() && !strval0(R[nj + 1]).empty())
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m_str_updates.push_back({ xi, vi + zstring(strval0(R[nj + 1])[0]), depth });
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m_str_updates.push_back({ xi, vi + zstring(strval0(R[nj + 1])[0]), score });
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if (ni + 1 < L.size() && !strval0(L[ni + 1]).empty())
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m_str_updates.push_back({ yj, vj + zstring(strval0(L[ni + 1])[0]), depth });
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m_str_updates.push_back({ yj, vj + zstring(strval0(L[ni + 1])[0]), score });
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i = 0;
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j = 0;
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++ni;
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@ -627,8 +655,8 @@ namespace sls {
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if (vi.length() == i) {
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// xi -> vi + vj[j]
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SASSERT(j < vj.length());
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m_str_updates.push_back({ xi, vi + zstring(vj[j]), depth});
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depth *= 2;
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m_str_updates.push_back({ xi, vi + zstring(vj[j]), score});
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score *= 2;
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i = 0;
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++ni;
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continue;
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@ -636,8 +664,8 @@ namespace sls {
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if (vj.length() == j) {
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// yj -> vj + vi[i]
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SASSERT(i < vi.length());
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m_str_updates.push_back({ yj, vj + zstring(vi[i]), depth });
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depth *= 2;
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m_str_updates.push_back({ yj, vj + zstring(vi[i]), score });
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score *= 2;
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j = 0;
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++nj;
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continue;
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@ -645,30 +673,33 @@ namespace sls {
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SASSERT(i < vi.length());
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SASSERT(j < vj.length());
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if (is_value(xi) && is_value(yj)) {
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if (vi[i] != vj[j])
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score = 1;
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++i, ++j;
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continue;
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}
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if (vi[i] == vj[j]) {
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++i, ++j;
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continue;
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}
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if (!is_value(xi)) {
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m_str_updates.push_back({ xi, vi.extract(0, i), depth });
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m_str_updates.push_back({ xi, vi.extract(0, i) + zstring(vj[j]), depth});
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m_str_updates.push_back({ xi, vi.extract(0, i), score });
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m_str_updates.push_back({ xi, vi.extract(0, i) + zstring(vj[j]), score});
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}
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if (!is_value(yj)) {
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m_str_updates.push_back({ yj, vj.extract(0, j), depth });
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m_str_updates.push_back({ yj, vj.extract(0, j) + zstring(vi[i]), depth });
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m_str_updates.push_back({ yj, vj.extract(0, j), score });
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m_str_updates.push_back({ yj, vj.extract(0, j) + zstring(vi[i]), score });
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}
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break;
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}
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for (; ni < L.size(); ++ni)
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if (!is_value(L[ni]))
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m_str_updates.push_back({ L[ni], zstring(), depth });
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if (!is_value(L[ni]) && !strval0(L[ni]).empty())
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m_str_updates.push_back({ L[ni], zstring(), 1 });
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for (; nj < R.size(); ++nj)
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if (!is_value(R[nj]))
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m_str_updates.push_back({ R[nj], zstring(), depth });
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if (!is_value(R[nj]) && !strval0(R[nj]).empty())
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m_str_updates.push_back({ R[nj], zstring(), 1 });
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return apply_update();
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}
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@ -1092,6 +1123,13 @@ namespace sls {
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sum_scores += score;
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for (auto const& [e, val, score] : m_int_updates)
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sum_scores += score;
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IF_VERBOSE(4,
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for (auto const& [e, val, score] : m_str_updates)
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verbose_stream() << mk_pp(e, m) << " := \"" << val << "\" score: " << score << "\n";
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for (auto const& [e, val, score] : m_int_updates)
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verbose_stream() << mk_pp(e, m) << " := " << val << " score: " << score << "\n";
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);
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while (!m_str_updates.empty() || !m_int_updates.empty()) {
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bool is_str_update = false;
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@ -1165,6 +1203,7 @@ namespace sls {
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if (m_initialized)
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return;
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m_initialized = true;
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expr_ref val(m);
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for (auto lit : ctx.unit_literals()) {
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auto e = ctx.atom(lit.var());
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expr* x, * y, * z;
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@ -1214,6 +1253,12 @@ namespace sls {
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if (len_r.is_unsigned())
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ev.max_length = std::min(ev.max_length, len_r.get_unsigned());
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}
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// TBD: assumes arithmetic is already initialized
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if (seq.str.is_length(t, x) && ctx.is_fixed(t, val) &&
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a.is_numeral(val, len_r) && len_r.is_unsigned()) {
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auto& ev = get_eval(x);
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ev.min_length = ev.max_length = len_r.get_unsigned();
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}
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}
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}
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@ -78,7 +78,8 @@ public:
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try {
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res = m_sls->check();
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}
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catch (z3_exception&) {
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catch (z3_exception& ex) {
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IF_VERBOSE(1, verbose_stream() << "SLS threw an exception: " << ex.what() << "\n");
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m_sls->collect_statistics(m_st);
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throw;
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}
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@ -98,7 +99,6 @@ public:
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}
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else
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mc = nullptr;
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}
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void operator()(goal_ref const& g,
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