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z3/src/sat/sat_simplifier.h
Nikolaj Bjorner 921423ec80 fix model conversions for incremental SAT, fix lookahead with ba_solver
Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
2017-12-12 10:43:23 -08:00

241 lines
8.6 KiB
C++

/*++
Copyright (c) 2011 Microsoft Corporation
Module Name:
sat_simplifier.h
Abstract:
SAT simplification procedures that use a "full" occurrence list:
Subsumption, Blocked Clause Removal, Variable Elimination, ...
Author:
Leonardo de Moura (leonardo) 2011-05-24.
Revision History:
--*/
#ifndef SAT_SIMPLIFIER_H_
#define SAT_SIMPLIFIER_H_
#include "sat/sat_types.h"
#include "sat/sat_clause.h"
#include "sat/sat_clause_set.h"
#include "sat/sat_clause_use_list.h"
#include "sat/sat_extension.h"
#include "sat/sat_watched.h"
#include "sat/sat_model_converter.h"
#include "util/heap.h"
#include "util/statistics.h"
#include "util/params.h"
namespace sat {
class solver;
class use_list {
vector<clause_use_list> m_use_list;
public:
void init(unsigned num_vars);
void insert(clause & c);
void block(clause & c);
void unblock(clause & c);
void erase(clause & c);
void erase(clause & c, literal l);
clause_use_list & get(literal l) { return m_use_list[l.index()]; }
clause_use_list const & get(literal l) const { return m_use_list[l.index()]; }
void finalize() { m_use_list.finalize(); }
};
class simplifier {
friend class ba_solver;
friend class elim_vars;
solver & s;
unsigned m_num_calls;
use_list m_use_list;
ext_use_list m_ext_use_list;
clause_set m_sub_todo;
svector<bin_clause> m_sub_bin_todo;
unsigned m_last_sub_trail_sz; // size of the trail since last cleanup
bool_var_set m_elim_todo;
bool m_need_cleanup;
tmp_clause m_dummy;
// simplifier extra variable fields.
svector<char> m_visited; // transient
// counters
int m_sub_counter;
int m_elim_counter;
// config
bool m_abce; // block clauses using asymmetric added literals
bool m_cce; // covered clause elimination
bool m_acce; // cce with asymetric literal addition
bool m_bca; // blocked (binary) clause addition.
unsigned m_bce_delay;
bool m_elim_blocked_clauses;
unsigned m_elim_blocked_clauses_at;
bool m_retain_blocked_clauses;
unsigned m_blocked_clause_limit;
bool m_incremental_mode;
bool m_resolution;
unsigned m_res_limit;
unsigned m_res_occ_cutoff;
unsigned m_res_occ_cutoff1;
unsigned m_res_occ_cutoff2;
unsigned m_res_occ_cutoff3;
unsigned m_res_lit_cutoff1;
unsigned m_res_lit_cutoff2;
unsigned m_res_lit_cutoff3;
unsigned m_res_cls_cutoff1;
unsigned m_res_cls_cutoff2;
bool m_subsumption;
unsigned m_subsumption_limit;
bool m_elim_vars;
bool m_elim_vars_bdd;
unsigned m_elim_vars_bdd_delay;
// stats
unsigned m_num_blocked_clauses;
unsigned m_num_covered_clauses;
unsigned m_num_subsumed;
unsigned m_num_elim_vars;
unsigned m_num_sub_res;
unsigned m_num_elim_lits;
unsigned m_num_bca;
bool m_learned_in_use_lists;
unsigned m_old_num_elim_vars;
struct size_lt {
bool operator()(clause const * c1, clause const * c2) const { return c1->size() > c2->size(); }
};
void checkpoint();
void initialize();
void init_visited();
void mark_visited(literal l) { m_visited[l.index()] = true; }
void unmark_visited(literal l) { m_visited[l.index()] = false; }
bool is_marked(literal l) const { return m_visited[l.index()] != 0; }
void mark_all_but(clause const & c, literal l);
void unmark_all(clause const & c);
void register_clauses(clause_vector & cs);
void remove_clause_core(clause & c);
void remove_clause(clause & c);
void remove_clause(clause & c, literal l);
void block_clause(clause & c);
void block_bin_clause_half(literal l1, literal l2);
void unblock_clause(clause & c);
void remove_bin_clause_half(literal l1, literal l2, bool learned);
bool_var get_min_occ_var(clause const & c) const;
bool subsumes1(clause const & c1, clause const & c2, literal & l);
void collect_subsumed1_core(clause const & c, clause_vector & out, literal_vector & out_lits, literal target);
void collect_subsumed1(clause const & c, clause_vector & out, literal_vector & out_lits);
clause_vector m_bs_cs;
literal_vector m_bs_ls;
void back_subsumption1(clause & c);
void back_subsumption1(literal l1, literal l2, bool learned);
literal get_min_occ_var0(clause const & c) const;
bool subsumes0(clause const & c1, clause const & c2);
void collect_subsumed0_core(clause const & c1, clause_vector & out, literal target);
void collect_subsumed0(clause const & c1, clause_vector & out);
void back_subsumption0(clause & c1);
bool cleanup_clause(clause & c, bool in_use_list);
bool cleanup_clause(literal_vector & c);
void elim_lit(clause & c, literal l);
void elim_dup_bins();
bool subsume_with_binaries();
void mark_as_not_learned_core(watch_list & wlist, literal l2);
void mark_as_not_learned(literal l1, literal l2);
void cleanup_watches();
void cleanup_clauses(clause_vector & cs, bool learned, bool vars_eliminated, bool in_use_lists);
bool is_external(bool_var v) const;
bool is_external(literal l) const { return is_external(l.var()); }
bool was_eliminated(bool_var v) const;
lbool value(bool_var v) const;
lbool value(literal l) const;
watch_list & get_wlist(literal l);
watch_list const & get_wlist(literal l) const;
struct blocked_clause_elim;
void elim_blocked_clauses();
bool single_threaded() const; // { return s.m_config.m_num_threads == 1; }
bool bce_enabled() const;
bool acce_enabled() const;
bool cce_enabled() const;
bool abce_enabled() const;
bool bca_enabled() const;
bool elim_vars_bdd_enabled() const;
bool elim_vars_enabled() const;
unsigned get_num_unblocked_bin(literal l) const;
unsigned get_to_elim_cost(bool_var v) const;
void order_vars_for_elim(bool_var_vector & r);
void collect_clauses(literal l, clause_wrapper_vector & r, bool include_blocked);
clause_wrapper_vector m_pos_cls;
clause_wrapper_vector m_neg_cls;
literal_vector m_new_cls;
bool resolve(clause_wrapper const & c1, clause_wrapper const & c2, literal l, literal_vector & r);
void save_clauses(model_converter::entry & mc_entry, clause_wrapper_vector const & cs);
void add_non_learned_binary_clause(literal l1, literal l2);
void remove_bin_clauses(literal l);
void remove_clauses(clause_use_list const & cs, literal l);
bool try_eliminate(bool_var v);
void elim_vars();
struct blocked_cls_report;
struct subsumption_report;
struct elim_var_report;
class scoped_finalize {
simplifier& s;
public:
scoped_finalize(simplifier& s) : s(s) {}
~scoped_finalize() { s.scoped_finalize_fn(); }
};
void scoped_finalize_fn();
public:
simplifier(solver & s, params_ref const & p);
~simplifier();
void insert_elim_todo(bool_var v) { m_elim_todo.insert(v); }
void reset_todos() {
m_elim_todo.reset();
m_sub_todo.reset();
m_sub_bin_todo.reset();
}
void operator()(bool learned);
void updt_params(params_ref const & p);
static void collect_param_descrs(param_descrs & d);
void finalize();
void collect_statistics(statistics & st) const;
void reset_statistics();
void propagate_unit(literal l);
void subsume();
};
};
#endif