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removing unit clauses and dependency manager, use minisat approach by tracking assumption literals directly also in clauses

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2021-09-20 15:10:03 -07:00
parent bb5ff8db24
commit 8ee54c665a
12 changed files with 60 additions and 179 deletions
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55
src/math/polysat/solver.cpp
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@ -37,7 +37,6 @@ namespace polysat {
solver::solver(reslimit& lim):
m_lim(lim),
m_viable(*this),
m_dm(m_value_manager, m_alloc),
m_linear_solver(*this),
m_conflict(*this),
m_bvars(),
@ -110,53 +109,31 @@ namespace polysat {
m_free_pvars.del_var_eh(v);
}
void solver::ext_constraint(signed_constraint c, unsigned dep, bool activate) {
VERIFY(at_base_level());
void solver::assign_eh(signed_constraint c, unsigned dep) {
SASSERT(at_base_level());
SASSERT(c);
SASSERT(activate || dep != null_dependency); // if we don't activate the constraint, we need the dependency to access it again later.
if (is_conflict())
return; // no need to do anything if we already have a conflict at base level
m_constraints.ensure_bvar(c.get());
clause_ref unit = clause::from_unit(m_level, c, mk_dep_ref(dep));
clause_ref unit = clause::from_unit(c);
m_constraints.store(unit.get(), *this);
c->set_unit_clause(unit.get());
if (dep != null_dependency && !c->is_external()) {
m_constraints.register_external(c);
m_trail.push_back(trail_instr_t::ext_constraint_i);
m_ext_constraint_trail.push_back(c.get());
}
LOG("New constraint: " << c);
#if ENABLE_LINEAR_SOLVER
m_linear_solver.new_constraint(*c.get());
#endif
if (activate)
assert_ext_constraint(c);
(void) dep; // dependencies go into justification
assign_bool(m_level, c.blit(), c->unit_clause(), nullptr);
#if 0
// just add them as axioms, tracked by dependencies
literal lit = c.blit();
m_bvars.assign(lit, m_level, nullptr, nullptr, dep);
m_trail.push_back(trail_instr_t::assign_bool_i);
m_search.push_boolean(lit);
#endif
}
void solver::assign_eh(unsigned dep, bool is_true) {
VERIFY(at_base_level());
if (is_conflict())
return; // no need to do anything if we already have a conflict at base level
signed_constraint c = m_constraints.lookup_external(dep);
if (!c) {
LOG("WARN: there is no constraint for dependency " << dep);
return;
}
assert_ext_constraint(is_true ? c : ~c);
}
void solver::assert_ext_constraint(signed_constraint c) {
SASSERT(at_base_level());
SASSERT(!is_conflict());
SASSERT(c->unit_clause());
if (c.bvalue(*this) == l_false)
m_conflict.set(~c); // we already added ~c => conflict
else if (c.is_always_false())
m_conflict.set(c);
else
assign_bool(m_level, c.blit(), c->unit_clause(), nullptr);
}
bool solver::can_propagate() {
return m_qhead < m_search.size() && !is_conflict();
@ -319,12 +296,6 @@ namespace polysat {
m_cjust_trail.pop_back();
break;
}
case trail_instr_t::ext_constraint_i: {
constraint* c = m_ext_constraint_trail.back();
m_constraints.unregister_external(c);
m_ext_constraint_trail.pop_back();
break;
}
default:
UNREACHABLE();
}
@ -699,7 +670,7 @@ namespace polysat {
}
unsigned solver::level(clause const& cl) {
unsigned lvl = 0;
unsigned lvl = base_level();
for (auto lit : cl) {
auto c = lit2cnstr(lit);
if (m_bvars.is_false(lit) || c.is_currently_false(*this))