mirror of
https://github.com/Z3Prover/z3
synced 2025-06-27 08:28:44 +00:00
merge with Miguel's fixes
Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner
commit
d2395ad897
5 changed files with 134 additions and 60 deletions
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@ -217,7 +217,7 @@ namespace sat {
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bool lookahead::select(unsigned level) {
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init_pre_selection(level);
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unsigned level_cand = std::max(m_config.m_level_cand, m_freevars.size() / 50);
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unsigned max_num_cand = level == 0 ? m_freevars.size() : level_cand / level;
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unsigned max_num_cand = (level > 0 && m_config.m_preselect) ? level_cand / level : m_freevars.size();
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max_num_cand = std::max(m_config.m_min_cutoff, max_num_cand);
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double sum = 0;
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@ -251,30 +251,40 @@ namespace sat {
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}
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TRACE("sat", display_candidates(tout););
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SASSERT(!m_candidates.empty());
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if (m_candidates.size() > max_num_cand) {
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unsigned j = m_candidates.size()/2;
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while (j > 0) {
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--j;
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sift_up(j);
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}
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while (true) {
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m_candidates[0] = m_candidates.back();
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m_candidates.pop_back();
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if (m_candidates.size() == max_num_cand) break;
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sift_up(0);
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}
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heap_sort();
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while (m_candidates.size() > max_num_cand) {
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m_candidates.pop_back();
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}
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SASSERT(!m_candidates.empty() && m_candidates.size() <= max_num_cand);
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TRACE("sat", display_candidates(tout););
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return true;
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}
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void lookahead::sift_up(unsigned j) {
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void lookahead::heap_sort() {
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if (m_candidates.size() > 1) {
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heapify();
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for (unsigned i = m_candidates.size() - 1; i > 0; --i) {
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candidate c = m_candidates[i];
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m_candidates[i] = m_candidates[0];
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m_candidates[0] = c;
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sift_down(0, i);
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}
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}
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}
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void lookahead::heapify() {
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unsigned i = 1 + (m_candidates.size() - 2) / 2;
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while(i > 0) {
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sift_down(--i, m_candidates.size());
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}
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}
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void lookahead::sift_down(unsigned j, unsigned sz) {
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unsigned i = j;
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candidate c = m_candidates[j];
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for (unsigned k = 2*j + 1; k < m_candidates.size(); i = k, k = 2*k + 1) {
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// pick largest parent
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if (k + 1 < m_candidates.size() && m_candidates[k].m_rating < m_candidates[k+1].m_rating) {
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for (unsigned k = 2 * j + 1; k < sz; i = k, k = 2 * k + 1) {
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// pick smallest child
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if (k + 1 < sz && m_candidates[k].m_rating > m_candidates[k + 1].m_rating) {
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++k;
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}
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if (c.m_rating <= m_candidates[k].m_rating) break;
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@ -452,6 +462,9 @@ namespace sat {
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case heule_unit_reward:
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heule_unit_scores();
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break;
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case march_cu_reward:
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march_cu_scores();
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break;
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case unit_literal_reward:
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heule_schur_scores();
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break;
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@ -502,7 +515,7 @@ namespace sat {
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for (bool_var x : m_freevars) {
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literal l(x, false);
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m_rating[l.var()] = heule_unit_score(l) * heule_unit_score(~l);
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}
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}
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}
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double lookahead::heule_unit_score(literal l) {
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@ -524,7 +537,23 @@ namespace sat {
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}
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#endif
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return sum;
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}
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}
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void lookahead::march_cu_scores() {
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for (bool_var x : m_freevars) {
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literal l(x, false);
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double pos = march_cu_score(l), neg = march_cu_score(~l);
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m_rating[l.var()] = 1024 * pos * neg + pos + neg + 1;
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}
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}
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double lookahead::march_cu_score(literal l) {
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double sum = 1.0 + literal_big_occs(~l);
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for (literal lit : m_binary[l.index()]) {
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if (is_undef(lit)) sum += literal_big_occs(lit);
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}
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return sum;
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}
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void lookahead::ensure_H(unsigned level) {
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while (m_H.size() <= level) {
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@ -920,7 +949,8 @@ namespace sat {
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}
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void lookahead::init() {
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m_delta_trigger = m_num_vars/10;
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m_delta_trigger = 0.0;
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m_delta_decrease = 0.0;
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m_config.m_dl_success = 0.8;
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m_inconsistent = false;
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m_qhead = 0;
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@ -1104,6 +1134,7 @@ namespace sat {
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m_lookahead_reward += num_units;
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break;
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case heule_unit_reward:
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case march_cu_reward:
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case heule_schur_reward:
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break;
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default:
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@ -1496,6 +1527,9 @@ namespace sat {
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case heule_unit_reward:
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m_lookahead_reward += pow(0.5, nonfixed);
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break;
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case march_cu_reward:
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m_lookahead_reward += 3.3 * pow(0.5, nonfixed - 2);
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break;
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case ternary_reward:
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if (nonfixed == 2) {
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m_lookahead_reward += (*m_heur)[l1.index()] * (*m_heur)[l2.index()];
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@ -1697,6 +1731,9 @@ namespace sat {
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case heule_unit_reward:
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m_lookahead_reward += 0.25;
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break;
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case march_cu_reward:
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m_lookahead_reward += 3.3;
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break;
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case unit_literal_reward:
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break;
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}
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@ -1727,6 +1764,9 @@ namespace sat {
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case heule_unit_reward:
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m_lookahead_reward += pow(0.5, sz);
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break;
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case march_cu_reward:
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m_lookahead_reward += 3.3 * pow(0.5, sz - 2);
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break;
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case ternary_reward:
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m_lookahead_reward = (double)0.001;
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break;
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@ -1736,10 +1776,17 @@ namespace sat {
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}
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// Sum_{ clause C that contains ~l } 1
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// FIXME: counts occurences of ~l; misleading
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double lookahead::literal_occs(literal l) {
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double result = m_binary[l.index()].size();
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// unsigned_vector const& nclauses = m_nary[(~l).index()];
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result += m_nary_count[(~l).index()];
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result += literal_big_occs(l);
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return result;
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}
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// Sum_{ clause C that contains ~l such that |C| > 2} 1
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// FIXME: counts occurences of ~l; misleading
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double lookahead::literal_big_occs(literal l) {
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double result = m_nary_count[(~l).index()];
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result += m_ternary_count[(~l).index()];
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return result;
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}
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@ -1753,36 +1800,37 @@ namespace sat {
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}
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}
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void lookahead::propagate() {
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while (!inconsistent() && m_qhead < m_trail.size()) {
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unsigned i = m_qhead;
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unsigned sz = m_trail.size();
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for (; i < sz && !inconsistent(); ++i) {
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for (; i < m_trail.size() && !inconsistent(); ++i) {
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literal l = m_trail[i];
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TRACE("sat", tout << "propagate " << l << " @ " << m_level << "\n";);
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propagate_binary(l);
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}
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while (m_qhead < sz && !inconsistent()) {
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while (m_qhead < m_trail.size() && !inconsistent()) {
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propagate_clauses(m_trail[m_qhead++]);
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}
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SASSERT(m_qhead == sz || (inconsistent() && m_qhead < sz));
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SASSERT(m_qhead == m_trail.size() || (inconsistent() && m_qhead < m_trail.size()));
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}
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TRACE("sat_verbose", display(tout << scope_lvl() << " " << (inconsistent()?"unsat":"sat") << "\n"););
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}
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void lookahead::compute_lookahead_reward() {
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init_lookahead_reward();
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TRACE("sat", display_lookahead(tout); );
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m_delta_decrease = pow(m_config.m_delta_rho, 1.0 / (double)m_lookahead.size());
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unsigned base = 2;
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bool change = true;
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bool first = true;
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literal last_changed = null_literal;
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while (change && !inconsistent()) {
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change = false;
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for (unsigned i = 0; !inconsistent() && i < m_lookahead.size(); ++i) {
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checkpoint();
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literal lit = m_lookahead[i].m_lit;
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if (lit == last_changed) {
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break;
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}
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if (is_fixed_at(lit, c_fixed_truth)) continue;
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unsigned level = base + m_lookahead[i].m_offset;
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if (m_stamp[lit.var()] >= level) {
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@ -1795,7 +1843,7 @@ namespace sat {
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unsigned old_trail_sz = m_trail.size();
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reset_lookahead_reward(lit);
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push_lookahead1(lit, level);
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if (!first) do_double(lit, base);
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do_double(lit, base);
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bool unsat = inconsistent();
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unsigned num_units = m_trail.size() - old_trail_sz;
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pop_lookahead1(lit, num_units);
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@ -1806,6 +1854,7 @@ namespace sat {
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propagate();
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init_lookahead_reward();
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change = true;
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last_changed = lit;
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}
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else {
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update_lookahead_reward(lit, level);
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@ -1815,13 +1864,9 @@ namespace sat {
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if (c_fixed_truth - 2 * m_lookahead.size() < base) {
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break;
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}
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if (first && !change) {
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first = false;
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change = true;
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}
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reset_lookahead_reward();
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init_lookahead_reward();
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// base += 2 * m_lookahead.size();
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base += 2 * m_lookahead.size();
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}
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reset_lookahead_reward();
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TRACE("sat", display_lookahead(tout); );
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@ -1877,6 +1922,7 @@ namespace sat {
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case ternary_reward: return l + r + (1 << 10) * l * r;
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case heule_schur_reward: return l * r;
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case heule_unit_reward: return l * r;
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case march_cu_reward: return 1024 * (1024 * l * r + l + r);
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case unit_literal_reward: return l * r;
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default: UNREACHABLE(); return l * r;
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}
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@ -1966,18 +2012,21 @@ namespace sat {
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}
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}
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void lookahead::do_double(literal l, unsigned& base) {
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if (!inconsistent() && scope_lvl() > 1 && dl_enabled(l)) {
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void lookahead::do_double(literal l, unsigned& base) {
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if (!inconsistent() && dl_enabled(l)) {
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if (get_lookahead_reward(l) > m_delta_trigger) {
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if (dl_no_overflow(base)) {
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++m_stats.m_double_lookahead_rounds;
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double_look(l, base);
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m_delta_trigger = get_lookahead_reward(l);
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dl_disable(l);
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if (!inconsistent()) {
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m_delta_trigger = get_lookahead_reward(l);
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dl_disable(l);
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}
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}
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}
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else {
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m_delta_trigger *= m_config.m_delta_rho;
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SASSERT(m_delta_decrease > 0.0);
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m_delta_trigger *= m_delta_decrease;
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}
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}
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}
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@ -1985,21 +2034,30 @@ namespace sat {
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void lookahead::double_look(literal l, unsigned& base) {
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SASSERT(!inconsistent());
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SASSERT(dl_no_overflow(base));
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unsigned dl_truth = base + 2 * m_lookahead.size() * (m_config.m_dl_max_iterations + 1);
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base += m_lookahead.size();
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unsigned dl_truth = base + m_lookahead.size() * m_config.m_dl_max_iterations;
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scoped_level _sl(*this, dl_truth);
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IF_VERBOSE(2, verbose_stream() << "double: " << l << " depth: " << m_trail_lim.size() << "\n";);
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init_lookahead_reward();
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assign(l);
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propagate();
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bool change = true;
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literal last_changed = null_literal;
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unsigned num_iterations = 0;
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while (change && num_iterations < m_config.m_dl_max_iterations && !inconsistent()) {
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change = false;
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num_iterations++;
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base += 2*m_lookahead.size();
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for (unsigned i = 0; !inconsistent() && i < m_lookahead.size(); ++i) {
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literal lit = m_lookahead[i].m_lit;
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if (is_fixed_at(lit, dl_truth)) continue;
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if (lit == last_changed) {
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SASSERT(change == false);
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break;
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}
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if (is_fixed_at(lit, dl_truth)) continue;
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if (base + m_lookahead.size() + m_lookahead[i].m_offset >= dl_truth) {
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change = false;
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break;
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}
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if (push_lookahead2(lit, base + m_lookahead[i].m_offset)) {
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TRACE("sat", tout << "unit: " << ~lit << "\n";);
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++m_stats.m_double_lookahead_propagations;
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@ -2008,10 +2066,12 @@ namespace sat {
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assign(~lit);
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propagate();
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change = true;
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last_changed = lit;
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init_lookahead_reward();
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}
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}
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SASSERT(dl_truth - 2 * m_lookahead.size() > base);
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base += 2 * m_lookahead.size();
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SASSERT(dl_truth >= base);
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}
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reset_lookahead_reward();
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SASSERT(m_level == dl_truth);
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@ -2051,14 +2111,13 @@ namespace sat {
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void lookahead::propagated(literal l) {
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assign(l);
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switch (m_search_mode) {
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case lookahead_mode::searching:
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break;
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case lookahead_mode::lookahead1:
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for (unsigned i = m_trail.size() - 1; i < m_trail.size() && !inconsistent(); ++i) {
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literal l = m_trail[i];
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TRACE("sat", tout << "propagate " << l << " @ " << m_level << "\n";);
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propagate_binary(l);
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}
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if (m_search_mode == lookahead_mode::lookahead1) {
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m_wstack.push_back(l);
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break;
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case lookahead_mode::lookahead2:
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break;
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}
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}
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@ -2166,10 +2225,11 @@ namespace sat {
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backtrack(m_cube_state.m_cube, m_cube_state.m_is_decision);
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return l_undef;
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}
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int prev_nfreevars = m_freevars.size();
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literal lit = choose();
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if (inconsistent()) {
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TRACE("sat", tout << "inconsistent: " << m_cube_state.m_cube << "\n";);
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m_cube_state.m_freevars_threshold = m_freevars.size();
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m_cube_state.m_freevars_threshold = prev_nfreevars;
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if (!backtrack(m_cube_state.m_cube, m_cube_state.m_is_decision)) return l_false;
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continue;
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}
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