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Merge branch 'opt' of https://github.com/nikolajbjorner/z3 into opt

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Nikolaj Bjorner 2017-06-01 14:50:37 -07:00
commit 55ba1e9178
52 changed files with 877 additions and 311 deletions
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32
src/sat/sat_lookahead.h
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@ -384,6 +384,7 @@ namespace sat {
candidate(bool_var v, float r): m_var(v), m_rating(r) {}
};
svector<candidate> m_candidates;
uint_set m_select_lookahead_vars;
float get_rating(bool_var v) const { return m_rating[v]; }
float get_rating(literal l) const { return get_rating(l.var()); }
@ -468,7 +469,11 @@ namespace sat {
for (bool_var const* it = m_freevars.begin(), * end = m_freevars.end(); it != end; ++it) {
SASSERT(is_undef(*it));
bool_var x = *it;
if (newbies || active_prefix(x)) {
if (!m_select_lookahead_vars.empty() && m_select_lookahead_vars.contains(x)) {
m_candidates.push_back(candidate(x, m_rating[x]));
sum += m_rating[x];
}
else if (newbies || active_prefix(x)) {
m_candidates.push_back(candidate(x, m_rating[x]));
sum += m_rating[x];
}
@ -1857,6 +1862,31 @@ namespace sat {
return search();
}
literal select_lookahead(bool_var_vector const& vars) {
m_search_mode = lookahead_mode::searching;
scoped_level _sl(*this, c_fixed_truth);
init();
if (inconsistent()) return null_literal;
inc_istamp();
for (auto v : vars) {
m_select_lookahead_vars.insert(v);
}
literal l = choose();
m_select_lookahead_vars.reset();
if (inconsistent()) return null_literal;
// assign unit literals that were found during search for lookahead.
unsigned num_assigned = 0;
for (literal lit : m_trail) {
if (!m_s.was_eliminated(lit.var()) && m_s.value(lit) != l_true) {
m_s.assign(lit, justification());
++num_assigned;
}
}
IF_VERBOSE(1, verbose_stream() << "(sat-lookahead :units " << num_assigned << ")\n";);
return l;
}
/**
\brief simplify set of clauses by extracting units from a lookahead at base level.
*/