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https://github.com/Z3Prover/z3
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include chronological backtracking, two-phase sat, xor inprocessing, probsat, ddfw
Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner
parent
46d23ea8d7
commit
d17248821a
32 changed files with 3246 additions and 654 deletions
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@ -19,7 +19,7 @@ Revision History:
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#ifndef SAT_SOLVER_H_
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#define SAT_SOLVER_H_
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#include <cmath>
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#include "sat/sat_types.h"
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#include "sat/sat_clause.h"
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#include "sat/sat_watched.h"
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@ -71,6 +71,8 @@ namespace sat {
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unsigned m_elim_var_res;
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unsigned m_elim_var_bdd;
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unsigned m_units;
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unsigned m_backtracks;
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unsigned m_backjumps;
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stats() { reset(); }
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void reset();
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void collect_statistics(statistics & st) const;
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@ -80,6 +82,8 @@ namespace sat {
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public:
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struct abort_solver {};
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protected:
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enum search_state { s_sat, s_unsat };
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bool m_checkpoint_enabled;
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config m_config;
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stats m_stats;
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@ -116,7 +120,9 @@ namespace sat {
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svector<char> m_lit_mark;
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svector<char> m_eliminated;
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svector<char> m_external;
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svector<unsigned> m_level;
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unsigned_vector m_touched;
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unsigned m_touch_index;
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literal_vector m_replay_assign;
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// branch variable selection:
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svector<unsigned> m_activity;
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unsigned m_activity_inc;
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@ -128,17 +134,27 @@ namespace sat {
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int m_action;
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double m_step_size;
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// phase
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svector<char> m_phase;
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svector<char> m_prev_phase;
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svector<bool> m_phase;
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svector<bool> m_best_phase;
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svector<bool> m_prev_phase;
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svector<char> m_assigned_since_gc;
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bool m_phase_cache_on;
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search_state m_search_state;
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unsigned m_search_unsat_conflicts;
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unsigned m_search_sat_conflicts;
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unsigned m_search_next_toggle;
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unsigned m_phase_counter;
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unsigned m_best_phase_size;
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unsigned m_rephase_lim;
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unsigned m_rephase_inc;
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var_queue m_case_split_queue;
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unsigned m_qhead;
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unsigned m_scope_lvl;
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unsigned m_search_lvl;
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ema m_fast_glue_avg;
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ema m_slow_glue_avg;
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ema m_fast_glue_backup;
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ema m_slow_glue_backup;
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ema m_trail_avg;
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literal_vector m_trail;
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clause_wrapper_vector m_clauses_to_reinit;
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std::string m_reason_unknown;
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@ -163,7 +179,7 @@ namespace sat {
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bool m_par_syncing_clauses;
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class lookahead* m_cuber;
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class local_search* m_local_search;
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class i_local_search* m_local_search;
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statistics m_aux_stats;
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@ -174,6 +190,7 @@ namespace sat {
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friend class simplifier;
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friend class scc;
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friend class big;
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friend class binspr;
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friend class elim_eqs;
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friend class asymm_branch;
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friend class probing;
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@ -184,6 +201,8 @@ namespace sat {
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friend class parallel;
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friend class lookahead;
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friend class local_search;
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friend class ddfw;
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friend class prob;
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friend class unit_walk;
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friend struct mk_stat;
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friend class elim_vars;
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@ -251,6 +270,7 @@ namespace sat {
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void attach_clause(clause & c, bool & reinit);
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void attach_clause(clause & c) { bool reinit; attach_clause(c, reinit); }
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void set_learned(clause& c, bool learned);
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void shrink(clause& c, unsigned old_sz, unsigned new_sz);
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void set_learned(literal l1, literal l2, bool learned);
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void set_learned1(literal l1, literal l2, bool learned);
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void add_ate(clause& c) { m_mc.add_ate(c); }
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@ -285,7 +305,7 @@ namespace sat {
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// -----------------------
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public:
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bool inconsistent() const override { return m_inconsistent; }
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unsigned num_vars() const override { return m_level.size(); }
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unsigned num_vars() const override { return m_justification.size(); }
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unsigned num_clauses() const override;
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void num_binary(unsigned& given, unsigned& learned) const;
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unsigned num_restarts() const { return m_restarts; }
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@ -293,7 +313,7 @@ namespace sat {
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void set_external(bool_var v) override;
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void set_non_external(bool_var v) override;
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bool was_eliminated(bool_var v) const { return m_eliminated[v] != 0; }
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void set_eliminated(bool_var v, bool f) override { m_eliminated[v] = f; }
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void set_eliminated(bool_var v, bool f) override;
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bool was_eliminated(literal l) const { return was_eliminated(l.var()); }
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unsigned scope_lvl() const { return m_scope_lvl; }
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unsigned search_lvl() const { return m_search_lvl; }
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@ -301,40 +321,55 @@ namespace sat {
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bool at_base_lvl() const override { return m_scope_lvl == 0; }
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lbool value(literal l) const { return static_cast<lbool>(m_assignment[l.index()]); }
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lbool value(bool_var v) const { return static_cast<lbool>(m_assignment[literal(v, false).index()]); }
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unsigned lvl(bool_var v) const { return m_level[v]; }
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unsigned lvl(literal l) const { return m_level[l.var()]; }
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unsigned lvl(bool_var v) const { return m_justification[v].level(); }
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unsigned lvl(literal l) const { return m_justification[l.var()].level(); }
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unsigned init_trail_size() const override { return at_base_lvl() ? m_trail.size() : m_scopes[0].m_trail_lim; }
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unsigned trail_size() const { return m_trail.size(); }
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literal trail_literal(unsigned i) const override { return m_trail[i]; }
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literal scope_literal(unsigned n) const { return m_trail[m_scopes[n].m_trail_lim]; }
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void assign(literal l, justification j) {
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TRACE("sat_assign", tout << l << " previous value: " << value(l) << "\n";);
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TRACE("sat_assign", tout << l << " previous value: " << value(l) << " j: " << j << "\n";);
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switch (value(l)) {
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case l_false: set_conflict(j, ~l); break;
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case l_undef: assign_core(l, scope_lvl(), j); break;
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case l_undef: assign_core(l, j); break;
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case l_true: return;
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}
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}
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void assign_core(literal l, unsigned lvl, justification jst);
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void assign_unit(literal l) { assign(l, justification()); }
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void assign_scoped(literal l) { assign(l, justification()); }
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void assign_unit(literal l) { assign(l, justification(0)); }
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void assign_scoped(literal l) { assign(l, justification(scope_lvl())); }
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void assign_core(literal l, justification jst);
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void set_conflict(justification c, literal not_l);
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void set_conflict(justification c) { set_conflict(c, null_literal); }
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void set_conflict() { set_conflict(justification()); }
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void set_conflict() { set_conflict(justification(0)); }
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lbool status(clause const & c) const;
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clause_offset get_offset(clause const & c) const { return cls_allocator().get_offset(&c); }
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void checkpoint() {
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if (!m_checkpoint_enabled) return;
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bool limit_reached() {
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if (!m_rlimit.inc()) {
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m_mc.reset();
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m_model_is_current = false;
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TRACE("sat", tout << "canceled\n";);
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m_reason_unknown = "sat.canceled";
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return true;
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}
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return false;
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}
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bool memory_exceeded() {
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++m_num_checkpoints;
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if (m_num_checkpoints < 10) return false;
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m_num_checkpoints = 0;
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return memory::get_allocation_size() > m_config.m_max_memory;
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}
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void checkpoint() {
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if (!m_checkpoint_enabled) return;
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if (limit_reached()) {
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throw solver_exception(Z3_CANCELED_MSG);
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}
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++m_num_checkpoints;
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if (m_num_checkpoints < 10) return;
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m_num_checkpoints = 0;
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if (memory::get_allocation_size() > m_config.m_max_memory) throw solver_exception(Z3_MAX_MEMORY_MSG);
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if (memory_exceeded()) {
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throw solver_exception(Z3_MAX_MEMORY_MSG);
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}
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}
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void set_par(parallel* p, unsigned id);
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bool canceled() { return !m_rlimit.inc(); }
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@ -358,7 +393,6 @@ namespace sat {
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void unmark_lit(literal l) { SASSERT(is_marked_lit(l)); m_lit_mark[l.index()] = false; }
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bool check_inconsistent();
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// -----------------------
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//
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// Propagation
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@ -369,6 +403,7 @@ namespace sat {
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bool propagate(bool update);
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protected:
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bool should_propagate() const;
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bool propagate_core(bool update);
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// -----------------------
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@ -391,6 +426,8 @@ namespace sat {
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void set_activity(bool_var v, unsigned act);
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lbool cube(bool_var_vector& vars, literal_vector& lits, unsigned backtrack_level);
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void display_lookahead_scores(std::ostream& out);
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protected:
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@ -398,6 +435,7 @@ namespace sat {
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unsigned m_restarts;
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unsigned m_restart_next_out;
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unsigned m_conflicts_since_restart;
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bool m_force_conflict_analysis;
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unsigned m_simplifications;
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unsigned m_restart_threshold;
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unsigned m_luby_idx;
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@ -427,22 +465,28 @@ namespace sat {
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void reinit_assumptions();
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bool tracking_assumptions() const;
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bool is_assumption(literal l) const;
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void simplify_problem();
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bool should_simplify() const;
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void do_simplify();
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void mk_model();
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bool check_model(model const & m) const;
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void restart(bool to_base);
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void do_restart(bool to_base);
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svector<size_t> m_last_positions;
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unsigned m_last_position_log;
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unsigned m_restart_logs;
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unsigned restart_level(bool to_base);
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void log_stats();
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bool should_cancel();
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bool should_restart() const;
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void set_next_restart();
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void update_activity(bool_var v, double p);
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bool reached_max_conflicts();
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void sort_watch_lits();
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void exchange_par();
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lbool check_par(unsigned num_lits, literal const* lits);
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lbool do_local_search(unsigned num_lits, literal const* lits);
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lbool do_ddfw_search(unsigned num_lits, literal const* lits);
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lbool do_prob_search(unsigned num_lits, literal const* lits);
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lbool invoke_local_search(unsigned num_lits, literal const* lits);
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lbool do_unit_walk();
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// -----------------------
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@ -451,7 +495,8 @@ namespace sat {
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//
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// -----------------------
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protected:
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void gc();
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bool should_gc() const;
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void do_gc();
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void gc_glue();
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void gc_psm();
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void gc_glue_psm();
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@ -492,18 +537,31 @@ namespace sat {
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unsigned m_conflict_lvl;
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literal_vector m_lemma;
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literal_vector m_ext_antecedents;
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bool use_backjumping(unsigned num_scopes);
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bool resolve_conflict();
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bool resolve_conflict_core();
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lbool resolve_conflict_core();
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void learn_lemma_and_backjump();
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unsigned get_max_lvl(literal consequent, justification js);
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inline unsigned update_max_level(literal lit, unsigned lvl2, bool& unique_max) {
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unsigned lvl1 = lvl(lit);
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if (lvl1 < lvl2) return lvl2;
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unique_max = lvl1 > lvl2;
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return lvl1;
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}
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unsigned get_max_lvl(literal consequent, justification js, bool& unique_max);
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void process_antecedent(literal antecedent, unsigned & num_marks);
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void resolve_conflict_for_unsat_core();
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void process_antecedent_for_unsat_core(literal antecedent);
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void process_consequent_for_unsat_core(literal consequent, justification const& js);
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void fill_ext_antecedents(literal consequent, justification js);
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unsigned skip_literals_above_conflict_level();
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void forget_phase_of_vars(unsigned from_lvl);
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void updt_phase_of_vars();
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void updt_phase_counters();
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void do_toggle_search_state();
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bool should_toggle_search_state();
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bool is_sat_phase() const;
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bool is_two_phase() const;
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bool should_rephase();
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void do_rephase();
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svector<char> m_diff_levels;
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unsigned num_diff_levels(unsigned num, literal const * lits);
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bool num_diff_levels_below(unsigned num, literal const* lits, unsigned max_glue, unsigned& glue);
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@ -518,8 +576,9 @@ namespace sat {
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bool implied_by_marked(literal lit);
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void reset_unmark(unsigned old_size);
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void updt_lemma_lvl_set();
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void reset_lemma_var_marks();
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bool minimize_lemma();
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bool minimize_lemma_binres();
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void reset_lemma_var_marks();
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bool dyn_sub_res();
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// -----------------------
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@ -531,7 +590,7 @@ namespace sat {
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void pop(unsigned num_scopes);
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void pop_reinit(unsigned num_scopes);
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void unassign_vars(unsigned old_sz);
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void unassign_vars(unsigned old_sz, unsigned new_lvl);
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void reinit_clauses(unsigned old_sz);
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literal_vector m_user_scope_literals;
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@ -556,7 +615,7 @@ namespace sat {
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//
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// -----------------------
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public:
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void cleanup(bool force);
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bool do_cleanup(bool force);
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void simplify(bool learned = true);
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void asymmetric_branching();
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unsigned scc_bin();
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