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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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121
src/sat/tactic/goal2sat.cpp
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@ -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();