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enable pb solver

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2017-05-07 18:03:38 -07:00
parent b915f78281
commit c49550ff2d
5 changed files with 154 additions and 7 deletions
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33
src/ast/rewriter/pb2bv_rewriter.cpp
View file

@ -53,6 +53,7 @@ struct pb2bv_rewriter::imp {
rational m_k;
vector<rational> m_coeffs;
bool m_keep_cardinality_constraints;
bool m_keep_pb_constraints;
unsigned m_min_arity;
template<lbool is_le>
@ -565,6 +566,7 @@ struct pb2bv_rewriter::imp {
m_trail(m),
m_args(m),
m_keep_cardinality_constraints(false),
m_keep_pb_constraints(false),
m_min_arity(2)
{}
@ -701,11 +703,33 @@ struct pb2bv_rewriter::imp {
if (m_keep_cardinality_constraints && f->get_arity() >= m_min_arity) return false;
result = m_sort.ge(full, pb.get_k(f).get_unsigned(), sz, args);
}
else if (pb.is_eq(f) && pb.get_k(f).is_unsigned() && has_small_coefficients(f) && m_keep_pb_constraints) {
return false;
}
else if (pb.is_le(f) && pb.get_k(f).is_unsigned() && has_small_coefficients(f) && m_keep_pb_constraints) {
return false;
}
else if (pb.is_ge(f) && pb.get_k(f).is_unsigned() && has_small_coefficients(f) && m_keep_pb_constraints) {
return false;
}
else {
result = mk_bv(f, sz, args);
}
return true;
}
bool has_small_coefficients(func_decl* f) {
unsigned sz = f->get_arity();
unsigned sum = 0;
for (unsigned i = 0; i < sz; ++i) {
rational c = pb.get_coeff(f, i);
if (!c.is_unsigned()) return false;
unsigned sum1 = sum + c.get_unsigned();
if (sum1 < sum) return false;
sum = sum1;
}
return true;
}
// definitions used for sorting network
literal mk_false() { return m.mk_false(); }
@ -733,6 +757,10 @@ struct pb2bv_rewriter::imp {
void keep_cardinality_constraints(bool f) {
m_keep_cardinality_constraints = f;
}
void keep_pb_constraints(bool f) {
m_keep_pb_constraints = f;
}
};
struct card2bv_rewriter_cfg : public default_rewriter_cfg {
@ -745,6 +773,7 @@ struct pb2bv_rewriter::imp {
}
card2bv_rewriter_cfg(imp& i, ast_manager & m):m_r(i, m) {}
void keep_cardinality_constraints(bool f) { m_r.keep_cardinality_constraints(f); }
void keep_pb_constraints(bool f) { m_r.keep_pb_constraints(f); }
};
class card_pb_rewriter : public rewriter_tpl<card2bv_rewriter_cfg> {
@ -754,6 +783,7 @@ struct pb2bv_rewriter::imp {
rewriter_tpl<card2bv_rewriter_cfg>(m, false, m_cfg),
m_cfg(i, m) {}
void keep_cardinality_constraints(bool f) { m_cfg.keep_cardinality_constraints(f); }
void keep_pb_constraints(bool f) { m_cfg.keep_pb_constraints(f); }
};
card_pb_rewriter m_rw;
@ -764,14 +794,17 @@ struct pb2bv_rewriter::imp {
m_num_translated(0),
m_rw(*this, m) {
m_rw.keep_cardinality_constraints(p.get_bool("keep_cardinality_constraints", false));
m_rw.keep_pb_constraints(p.get_bool("keep_pb_constraints", false));
}
void updt_params(params_ref const & p) {
m_params.append(p);
m_rw.keep_cardinality_constraints(m_params.get_bool("keep_cardinality_constraints", false));
m_rw.keep_pb_constraints(m_params.get_bool("keep_pb_constraints", false));
}
void collect_param_descrs(param_descrs& r) const {
r.insert("keep_cardinality_constraints", CPK_BOOL, "(default: true) retain cardinality constraints (don't bit-blast them) and use built-in cardinality solver");
r.insert("keep_pb_constraints", CPK_BOOL, "(default: true) retain pb constraints (don't bit-blast them) and use built-in pb solver");
}
unsigned get_num_steps() const { return m_rw.get_num_steps(); }

3
src/sat/card_extension.cpp
View file

@ -49,6 +49,9 @@ namespace sat {
m_max_sum(0) {
for (unsigned i = 0; i < wlits.size(); ++i) {
m_wlits[i] = wlits[i];
if (m_max_sum + wlits[i].first < m_max_sum) {
throw default_exception("addition of pb coefficients overflows");
}
m_max_sum += wlits[i].first;
}
}

1
src/sat/sat_params.pyg
View file

@ -27,6 +27,7 @@ def_module_params('sat',
('drat.file', SYMBOL, '', 'file to dump DRAT proofs'),
('drat.check', BOOL, False, 'build up internal proof and check'),
('cardinality.solver', BOOL, False, 'use cardinality solver'),
('pb.solver', BOOL, False, 'use pb solver'),
('xor.solver', BOOL, False, 'use xor solver'),
('local_search_threads', UINT, 0, 'number of local search threads to find satisfiable solution'),
('local_search', BOOL, False, 'use local search instead of CDCL'),

3
src/sat/sat_solver/inc_sat_solver.cpp
View file

@ -216,7 +216,8 @@ public:
m_params.append(p);
sat_params p1(p);
m_params.set_bool("elim_vars", false);
m_params.set_bool("keep_cardinality_constraints", p1.cardinality_solver());
m_params.set_bool("keep_cardinality_constraints", p1.pb_solver() || p1.cardinality_solver());
m_params.set_bool("keep_pb_constraints", p1.pb_solver());
m_params.set_bool("xor_solver", p1.xor_solver());
m_solver.updt_params(m_params);
m_optimize_model = m_params.get_bool("optimize_model", false);

121
src/sat/tactic/goal2sat.cpp
View file

@ -419,6 +419,103 @@ struct goal2sat::imp {
}
}
typedef std::pair<unsigned, sat::literal> wliteral;
void check_unsigned(rational const& c) {
if (!c.is_unsigned()) {
throw default_exception("unsigned coefficient expected");
}
}
void convert_to_wlits(app* t, sat::literal_vector const& lits, svector<wliteral>& wlits) {
for (unsigned i = 0; i < lits.size(); ++i) {
rational c = pb.get_coeff(t, i);
check_unsigned(c);
wlits.push_back(std::make_pair(c.get_unsigned(), lits[i]));
}
}
void convert_pb_args(app* t, svector<wliteral>& wlits) {
sat::literal_vector lits;
convert_pb_args(t->get_num_args(), lits);
convert_to_wlits(t, lits, wlits);
}
void convert_pb_ge(app* t, bool root, bool sign) {
rational k = pb.get_k(t);
check_unsigned(k);
svector<wliteral> wlits;
convert_pb_args(t, wlits);
unsigned sz = m_result_stack.size();
if (root) {
m_result_stack.reset();
m_ext->add_pb_ge(sat::null_bool_var, wlits, k.get_unsigned());
}
else {
sat::bool_var v = m_solver.mk_var(true);
sat::literal lit(v, sign);
m_ext->add_pb_ge(v, wlits, k.get_unsigned());
TRACE("goal2sat", tout << "root: " << root << " lit: " << lit << "\n";);
m_result_stack.shrink(sz - t->get_num_args());
m_result_stack.push_back(lit);
}
}
void convert_pb_le(app* t, bool root, bool sign) {
rational k = pb.get_k(t);
k.neg();
svector<wliteral> wlits;
convert_pb_args(t, wlits);
for (unsigned i = 0; i < wlits.size(); ++i) {
wlits[i].second.neg();
k += rational(wlits[i].first);
}
check_unsigned(k);
unsigned sz = m_result_stack.size();
if (root) {
m_result_stack.reset();
m_ext->add_pb_ge(sat::null_bool_var, wlits, k.get_unsigned());
}
else {
sat::bool_var v = m_solver.mk_var(true);
sat::literal lit(v, sign);
m_ext->add_pb_ge(v, wlits, k.get_unsigned());
TRACE("goal2sat", tout << "root: " << root << " lit: " << lit << "\n";);
m_result_stack.shrink(sz - t->get_num_args());
m_result_stack.push_back(lit);
}
}
void convert_pb_eq(app* t, bool root, bool sign) {
rational k = pb.get_k(t);
SASSERT(k.is_unsigned());
svector<wliteral> wlits;
convert_pb_args(t, wlits);
sat::bool_var v1 = root ? sat::null_bool_var : m_solver.mk_var(true);
sat::bool_var v2 = root ? sat::null_bool_var : m_solver.mk_var(true);
m_ext->add_pb_ge(v1, wlits, k.get_unsigned());
k.neg();
for (unsigned i = 0; i < wlits.size(); ++i) {
wlits[i].second.neg();
k += rational(wlits[i].first);
}
check_unsigned(k);
m_ext->add_pb_ge(v2, wlits, k.get_unsigned());
if (root) {
m_result_stack.reset();
}
else {
sat::literal l1(v1, false), l2(v2, false);
sat::bool_var v = m_solver.mk_var();
sat::literal l(v, false);
mk_clause(~l, l1);
mk_clause(~l, l2);
mk_clause(~l1, ~l2, l);
m_result_stack.shrink(m_result_stack.size() - t->get_num_args());
m_result_stack.push_back(l);
}
}
void convert_at_least_k(app* t, rational k, bool root, bool sign) {
SASSERT(k.is_unsigned());
sat::literal_vector lits;
@ -529,16 +626,28 @@ struct goal2sat::imp {
convert_at_least_k(t, pb.get_k(t), root, sign);
break;
case OP_PB_LE:
SASSERT(pb.has_unit_coefficients(t));
convert_at_most_k(t, pb.get_k(t), root, sign);
if (pb.has_unit_coefficients(t)) {
convert_at_most_k(t, pb.get_k(t), root, sign);
}
else {
convert_pb_le(t, root, sign);
}
break;
case OP_PB_GE:
SASSERT(pb.has_unit_coefficients(t));
convert_at_least_k(t, pb.get_k(t), root, sign);
if (pb.has_unit_coefficients(t)) {
convert_at_least_k(t, pb.get_k(t), root, sign);
}
else {
convert_pb_ge(t, root, sign);
}
break;
case OP_PB_EQ:
SASSERT(pb.has_unit_coefficients(t));
convert_eq_k(t, pb.get_k(t), root, sign);
if (pb.has_unit_coefficients(t)) {
convert_eq_k(t, pb.get_k(t), root, sign);
}
else {
convert_pb_eq(t, root, sign);
}
break;
default:
UNREACHABLE();