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adding incremental cubing from API

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2017-09-28 09:06:17 -07:00
parent 260c27d58a
commit e507a6ccd1
18 changed files with 194 additions and 9 deletions
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62
src/sat/sat_lookahead.cpp
View file

@ -2353,6 +2353,16 @@ namespace sat {
}
lbool lookahead::cube() {
#if 0
literal_vector lits;
while (true) {
lbool result = cube(lits);
if (lits.empty() || result != l_undef) {
return result;
}
display_cube(std::cout, cube);
}
#endif
lbool result = l_false;
init_search();
m_model.reset();
@ -2394,6 +2404,58 @@ namespace sat {
}
}
lbool lookahead::cube(literal_vector& lits) {
lits.reset();
bool is_first = (m_cube_state.m_lit == null_literal);
if (is_first) {
init_search();
m_model.reset();
}
scoped_level _sl(*this, c_fixed_truth);
m_search_mode = lookahead_mode::searching;
unsigned depth = 0;
if (!is_first) {
goto pick_up_work;
}
while (true) {
TRACE("sat", display(tout););
inc_istamp();
checkpoint();
m_cube_state.m_lit = choose();
if (inconsistent()) {
TRACE("sat", tout << "inconsistent: " << cube << "\n";);
m_cube_state.m_freevars_threshold = m_freevars.size();
if (!backtrack(m_cube_state.m_cube, m_cube_state.m_is_decision)) return m_cube_state.m_result;
continue;
}
if (m_cube_state.m_lit == null_literal) {
return l_true;
}
depth = m_cube_state.m_cube.size();
if ((m_config.m_cube_cutoff != 0 && depth == m_config.m_cube_cutoff) ||
(m_config.m_cube_cutoff == 0 && m_freevars.size() < m_cube_state.m_freevars_threshold)) {
m_cube_state.m_freevars_threshold *= (1.0 - pow(m_config.m_cube_fraction, depth));
m_cube_state.m_result = l_undef;
set_conflict();
if (!backtrack(m_cube_state.m_cube, m_cube_state.m_is_decision)) return m_cube_state.m_result;
lits.append(m_cube_state.m_cube);
return l_undef;
}
pick_up_work:
TRACE("sat", tout << "choose: " << m_cube_state.m_lit << " cube: " << m_cube_state.m_cube << "\n";);
++m_stats.m_decisions;
push(m_cube_state.m_lit, c_fixed_truth);
m_cube_state.m_cube.push_back(m_cube_state.m_lit);
m_cube_state.m_is_decision.push_back(true);
SASSERT(inconsistent() || !is_unsat());
}
lbool result = m_cube_state.m_result;
m_cube_state.reset();
return result;
}
void lookahead::init_model() {
m_model.reset();
for (unsigned i = 0; i < m_num_vars; ++i) {

19
src/sat/sat_lookahead.h
View file

@ -139,6 +139,22 @@ namespace sat {
};
#endif
struct cube_state {
svector<bool> m_is_decision;
literal_vector m_cube;
literal m_lit;
lbool m_result;
double m_freevars_threshold;
cube_state() { reset(); }
void reset() {
m_is_decision.reset();
m_cube.reset();
m_lit = null_literal;
m_result = l_false;
m_freevars_threshold = 0;
}
};
config m_config;
double m_delta_trigger;
@ -202,6 +218,7 @@ namespace sat {
lookahead_mode m_search_mode; // mode of search
stats m_stats;
model m_model;
cube_state m_cube_state;
// ---------------------------------------
// truth values
@ -537,6 +554,8 @@ namespace sat {
*/
lbool cube();
lbool cube(literal_vector& lits);
literal select_lookahead(literal_vector const& assumptions, bool_var_vector const& vars);
/**
\brief simplify set of clauses by extracting units from a lookahead at base level.

14
src/sat/sat_solver.cpp
View file

@ -63,6 +63,7 @@ namespace sat {
m_next_simplify = 0;
m_num_checkpoints = 0;
m_simplifications = 0;
m_cuber = nullptr;
}
solver::~solver() {
@ -836,6 +837,19 @@ namespace sat {
return lh.select_lookahead(assumptions, vars);
}
lbool solver::cube(literal_vector& lits) {
if (!m_cuber) {
m_cuber = alloc(lookahead, *this);
}
lbool result = m_cuber->cube(lits);
if (result == l_false) {
dealloc(m_cuber);
m_cuber = nullptr;
}
return result;
}
// -----------------------
//
// Search

5
src/sat/sat_solver.h
View file

@ -156,6 +156,8 @@ namespace sat {
unsigned m_par_num_vars;
bool m_par_syncing_clauses;
class lookahead* m_cuber;
statistics m_aux_stats;
void del_clauses(clause * const * begin, clause * const * end);
@ -362,6 +364,7 @@ namespace sat {
char const* get_reason_unknown() const { return m_reason_unknown.c_str(); }
literal select_lookahead(literal_vector const& assumptions, bool_var_vector const& vars);
lbool cube(literal_vector& lits);
protected:
unsigned m_conflicts_since_init;
@ -404,7 +407,7 @@ namespace sat {
void exchange_par();
lbool check_par(unsigned num_lits, literal const* lits);
lbool lookahead_search();
lbool lookahead_cube();
lbool lookahead_cube();
lbool do_local_search(unsigned num_lits, literal const* lits);
lbool do_ccc();

19
src/sat/sat_solver/inc_sat_solver.cpp
View file

@ -344,6 +344,25 @@ public:
expr_ref result(lit2expr[l.index()].get(), m);
return result;
}
virtual expr_ref cube() {
sat::literal_vector lits;
lbool result = m_solver.cube(lits);
if (result == l_false || lits.empty()) {
return expr_ref(m.mk_false(), m);
}
if (result == l_true) {
return expr_ref(m.mk_true(), m);
}
expr_ref_vector fmls(m);
expr_ref_vector lit2expr(m);
lit2expr.resize(m_solver.num_vars() * 2);
m_map.mk_inv(lit2expr);
for (sat::literal l : lits) {
fmls.push_back(lit2expr[l.index()].get());
}
return mk_and(fmls);
}
virtual void get_lemmas(expr_ref_vector & lemmas) {
if (!m_internalized) return;
sat2goal s2g;