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moving out viable functionality

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2021-06-21 15:50:04 -07:00
parent 19099244c4
commit 6f93ed8dc2
9 changed files with 242 additions and 121 deletions
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70
src/math/polysat/solver.cpp
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@ -34,6 +34,7 @@ namespace polysat {
return *m_pdd[sz];
}
#if 0
dd::fdd const& solver::sz2bits(unsigned sz) {
m_bits.reserve(sz + 1);
auto* bits = m_bits[sz];
@ -70,11 +71,14 @@ namespace polysat {
return var2bits(v).find_hint(m_viable[v], m_value[v], val);
}
#endif
solver::solver(reslimit& lim):
m_lim(lim),
m_linear_solver(*this),
m_bdd(1000),
m_vble(*this),
// m_bdd(1000),
m_dm(m_value_manager, m_alloc),
m_linear_solver(*this),
m_free_vars(m_activity),
m_bvars(),
m_constraints(m_bvars) {
@ -85,31 +89,6 @@ namespace polysat {
m_conflict.reset();
}
#if POLYSAT_LOGGING_ENABLED
void solver::log_viable() {
// only for small problems
if (m_viable.size() < 10) {
for (pvar v = 0; v < m_viable.size(); ++v) {
log_viable(v);
}
}
}
void solver::log_viable(pvar v) {
if (size(v) <= 5) {
vector<rational> xs;
for (rational x = rational::zero(); x < rational::power_of_two(size(v)); x += 1) {
if (is_viable(v, x)) {
xs.push_back(x);
}
}
LOG("Viable for pvar " << v << ": " << xs);
} else {
LOG("Viable for pvar " << v << ": <range too big>");
}
}
#endif
bool solver::should_search() {
return
m_lim.inc() &&
@ -126,7 +105,7 @@ namespace polysat {
LOG("Free variables: " << m_free_vars);
LOG("Assignment: " << assignments_pp(*this));
if (!m_conflict.empty()) LOG("Conflict: " << m_conflict);
IF_LOGGING(log_viable());
IF_LOGGING(m_vble.log());
if (pending_disjunctive_lemma()) { LOG_H2("UNDEF (handle lemma externally)"); return l_undef; }
else if (is_conflict() && at_base_level()) { LOG_H2("UNSAT"); return l_false; }
@ -140,10 +119,10 @@ namespace polysat {
}
unsigned solver::add_var(unsigned sz) {
pvar v = m_viable.size();
pvar v = m_value.size();
m_value.push_back(rational::zero());
m_justification.push_back(justification::unassigned());
m_viable.push_back(m_bdd.mk_true());
m_vble.push();
m_cjust.push_back(constraints());
m_watch.push_back(ptr_vector<constraint>());
m_activity.push_back(0);
@ -161,8 +140,8 @@ namespace polysat {
void solver::del_var() {
// TODO also remove v from all learned constraints.
pvar v = m_viable.size() - 1;
m_viable.pop_back();
pvar v = m_value.size() - 1;
m_vble.pop();
m_cjust.pop_back();
m_value.pop_back();
m_justification.pop_back();
@ -189,7 +168,7 @@ namespace polysat {
auto slack = add_var(sz);
auto q = p + var(slack);
add_eq(q, dep); // TODO: 'dep' now refers to two constraints; this is not yet supported
auto non_zero = sz2bits(sz).non_zero();
auto non_zero = m_vble.sz2bits(sz).non_zero();
return m_constraints.viable(m_level, pos_t, slack, non_zero, mk_dep_ref(dep));
}
@ -287,7 +266,7 @@ namespace polysat {
void solver::propagate(pvar v, rational const& val, constraint& c) {
LOG("Propagation: " << assignment_pp(*this, v, val) << ", due to " << c);
if (is_viable(v, val)) {
if (m_vble.is_viable(v, val)) {
m_free_vars.del_var_eh(v);
assign_core(v, val, justification::propagation(m_level));
}
@ -326,10 +305,7 @@ namespace polysat {
break;
}
case trail_instr_t::viable_i: {
auto p = m_viable_trail.back();
LOG_V("Undo viable_i");
m_viable[p.first] = p.second;
m_viable_trail.pop_back();
m_vble.pop_viable();
break;
}
case trail_instr_t::assign_i: {
@ -418,9 +394,9 @@ namespace polysat {
void solver::decide(pvar v) {
LOG("Decide v" << v);
IF_LOGGING(log_viable(v));
IF_LOGGING(m_vble.log(v));
rational val;
switch (find_viable(v, val)) {
switch (m_vble.find_viable(v, val)) {
case dd::find_t::empty:
// NOTE: all such cases should be discovered elsewhere (e.g., during propagation/narrowing)
// (fail here in debug mode so we notice if we miss some)
@ -445,7 +421,7 @@ namespace polysat {
else
++m_stats.m_num_propagations;
LOG(assignment_pp(*this, v, val) << " by " << j);
SASSERT(is_viable(v, val));
SASSERT(m_vble.is_viable(v, val));
SASSERT(std::all_of(assignment().begin(), assignment().end(), [v](auto p) { return p.first != v; }));
m_value[v] = val;
m_search.push_assignment(v, val);
@ -531,7 +507,7 @@ namespace polysat {
pvar conflict_var = null_var;
clause_ref lemma;
for (auto v : m_conflict.vars(m_constraints))
if (!has_viable(v)) {
if (!m_vble.has_viable(v)) {
SASSERT(conflict_var == null_var || conflict_var == v); // at most one variable can be empty
conflict_var = v;
}
@ -799,7 +775,7 @@ namespace polysat {
// Guess a literal from the given clause; returns the guessed constraint
sat::literal solver::decide_bool(clause& lemma) {
LOG_H3("Guessing literal in lemma: " << lemma);
IF_LOGGING(log_viable());
IF_LOGGING(m_vble.log());
LOG("Boolean assignment: " << m_bvars);
// To make a guess, we need to find an unassigned literal that is not false in the current model.
@ -887,20 +863,14 @@ namespace polysat {
rational val = m_value[v];
LOG_H3("Reverting decision: pvar " << v << " := " << val);
SASSERT(m_justification[v].is_decision());
bdd viable = m_viable[v];
constraints just(m_cjust[v]);
backjump(m_justification[v].level()-1);
// Since decision "v -> val" caused a conflict, we may keep all
// viability restrictions on v and additionally exclude val.
// TODO: viability restrictions on 'v' must have happened before decision on 'v'. Do we really need to save/restore m_viable here?
SASSERT(m_viable[v] == viable); // check this with assertion
SASSERT(m_cjust[v] == just); // check this with assertion
// push_viable(v);
// m_viable[v] = viable;
// for (unsigned i = m_cjust[v].size(); i < just.size(); ++i)
// push_cjust(v, just[i]);
add_non_viable(v, val);
m_vble.add_non_viable(v, val);
auto confl = std::move(m_conflict);
m_conflict.reset();