mirror of
https://github.com/Z3Prover/z3
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updates
Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner
parent
ba0ec79375
commit
1c7cb87900
3 changed files with 118 additions and 120 deletions
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@ -27,7 +27,6 @@ namespace sat {
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void local_search::init() {
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best_solution.resize(num_vars() + 1, false);
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constraint_slack.resize(num_constraints(), 0);
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cur_solution.resize(num_vars() + 1, false);
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m_index_in_unsat_stack.resize(num_constraints(), 0);
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coefficient_in_ob_constraint.resize(num_vars() + 1, 0);
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@ -39,22 +38,16 @@ namespace sat {
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for (bool_var v = 1; v <= num_vars(); ++v) {
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bool_vector is_neighbor(num_vars() + 1, false);
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var_neighbor.push_back(bool_var_vector());
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for (unsigned i = 0; i < m_vars[v].m_watch[true].size(); ++i) {
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unsigned c = m_vars[v].m_watch[true][i];
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for (unsigned j = 0; j < constraint_term[c].size(); ++j) {
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bool_var w = constraint_term[c][j].var_id;
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if (w == v || is_neighbor[w]) continue;
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is_neighbor[w] = true;
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var_neighbor.back().push_back(w);
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}
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}
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for (unsigned i = 0; i < m_vars[v].m_watch[false].size(); ++i) {
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unsigned c = m_vars[v].m_watch[false][i];
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for (unsigned j = 0; j < constraint_term[c].size(); ++j) {
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bool_var w = constraint_term[c][j].var_id;
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if (w == v || is_neighbor[w]) continue;
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is_neighbor[w] = true;
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var_neighbor.back().push_back(w);
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bool pol = true;
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for (unsigned k = 0; k < 2; pol = !pol, k++) {
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for (unsigned i = 0; i < m_vars[v].m_watch[pol].size(); ++i) {
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constraint const& c = m_constraints[m_vars[v].m_watch[pol][i]];
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for (unsigned j = 0; j < c.size(); ++j) {
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bool_var w = c[j].var();
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if (w == v || is_neighbor[w]) continue;
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is_neighbor[w] = true;
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var_neighbor.back().push_back(w);
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}
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}
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}
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}
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@ -78,14 +71,15 @@ namespace sat {
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// figure out slack, and init unsat stack
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void local_search::init_slack() {
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for (unsigned c = 0; c < num_constraints(); ++c) {
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for (unsigned i = 0; i < constraint_term[c].size(); ++i) {
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unsigned v = constraint_term[c][i].var_id;
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if (cur_solution[v] == constraint_term[c][i].sense)
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--constraint_slack[c];
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constraint & cn = m_constraints[c];
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for (unsigned i = 0; i < cn.size(); ++i) {
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bool_var v = cn[i].var();
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if (cur_solution[v] == is_pos(cn[i]))
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--cn.m_slack;
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}
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// constraint_slack[c] = constraint_k[c] - true_terms_count[c];
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// violate the at-most-k constraint
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if (constraint_slack[c] < 0)
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if (cn.m_slack < 0)
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unsat(c);
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}
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}
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@ -98,21 +92,21 @@ namespace sat {
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int_vector& falsep = m_vars[v].m_watch[!is_true];
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for (unsigned i = 0; i < falsep.size(); ++i) {
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int c = falsep[i];
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constraint& c = m_constraints[falsep[i]];
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// will --slack
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if (constraint_slack[c] <= 0) {
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if (c.m_slack <= 0) {
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dec_slack_score(v);
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if (constraint_slack[c] == 0)
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if (c.m_slack == 0)
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dec_score(v);
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}
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}
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for (unsigned i = 0; i < truep.size(); ++i) {
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int c = truep[i];
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constraint& c = m_constraints[truep[i]];
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// will --true_terms_count[c]
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// will ++slack
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if (constraint_slack[c] <= -1) {
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if (c.m_slack <= -1) {
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inc_slack_score(v);
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if (constraint_slack[c] == -1)
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if (c.m_slack == -1)
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inc_score(v);
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}
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}
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@ -131,7 +125,10 @@ namespace sat {
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}
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void local_search::reinit_orig() {
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constraint_slack = constraint_k;
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for (unsigned i = 0; i < m_constraints.size(); ++i) {
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constraint& c = m_constraints[i];
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c.m_slack = c.m_k;
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}
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// init unsat stack
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m_unsat_stack.reset();
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@ -142,16 +139,14 @@ namespace sat {
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// init varibale information
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// variable 0 is the virtual variable
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time_stamp.reserve(m_vars.size());
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cscc.reserve(m_vars.size());
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m_vars[0].m_score = INT_MIN;
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m_vars[0].m_conf_change = false;
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m_vars[0].m_slack_score = INT_MIN;
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cscc[0] = 0;
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time_stamp[0] = max_steps + 1;
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m_vars[0].m_cscc = 0;
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m_vars[0].m_time_stamp = max_steps + 1;
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for (unsigned i = 1; i < m_vars.size(); ++i) {
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time_stamp[i] = 0;
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cscc[i] = 1;
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m_vars[i].m_time_stamp = 0;
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m_vars[i].m_cscc = 1;
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m_vars[i].m_conf_change = true;
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m_vars[i].m_in_goodvar_stack = false;
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m_vars[i].m_score = 0;
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@ -191,17 +186,14 @@ namespace sat {
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}
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void local_search::add_cardinality(unsigned sz, literal const* c, unsigned k) {
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unsigned id = num_constraints();
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constraint_term.push_back(svector<term>());
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unsigned id = m_constraints.size();
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m_constraints.push_back(constraint(k));
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for (unsigned i = 0; i < sz; ++i) {
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m_vars.reserve(c[i].var() + 1);
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term t;
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t.var_id = c[i].var();
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t.sense = c[i].sign();
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m_vars[t.var_id].m_watch[t.sense].push_back(id);
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constraint_term[id].push_back(t);
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literal t(~c[i]);
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m_vars[t.var()].m_watch[is_pos(t)].push_back(id);
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m_constraints.back().m_literals.push_back(t);
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}
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constraint_k.push_back(k);
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}
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local_search::local_search(solver& s) {
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@ -314,7 +306,7 @@ namespace sat {
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}
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flipvar = pick_var();
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flip(flipvar);
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time_stamp[flipvar] = step;
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m_vars[flipvar].m_time_stamp = step;
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}
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if (tries % 10 == 0) {
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// take a look at watch
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@ -344,7 +336,7 @@ namespace sat {
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// already changed truth value!!!!
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cur_solution[flipvar] = !cur_solution[flipvar];
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unsigned v, c;
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unsigned v;
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int org_flipvar_score = score(flipvar);
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int org_flipvar_slack_score = slack_score(flipvar);
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@ -354,37 +346,37 @@ namespace sat {
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// update related clauses and neighbor vars
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for (unsigned i = 0; i < truep.size(); ++i) {
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c = truep[i];
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constraint & c = m_constraints[truep[i]];
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//++true_terms_count[c];
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--constraint_slack[c];
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switch (constraint_slack[c]) {
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--c.m_slack;
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switch (c.m_slack) {
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case -2: // from -1 to -2
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for (unsigned j = 0; j < constraint_term[c].size(); ++j) {
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v = constraint_term[c][j].var_id;
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for (unsigned j = 0; j < c.size(); ++j) {
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v = c[j].var();
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// flipping the slack increasing var will no long sat this constraint
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if (cur_solution[v] == constraint_term[c][j].sense) {
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if (cur_solution[v] == is_pos(c[j])) {
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//score[v] -= constraint_weight[c];
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dec_score(v);
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}
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}
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break;
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case -1: // from 0 to -1: sat -> unsat
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for (unsigned j = 0; j < constraint_term[c].size(); ++j) {
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v = constraint_term[c][j].var_id;
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++cscc[v];
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for (unsigned j = 0; j < c.size(); ++j) {
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v = c[j].var();
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inc_cscc(v);
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//score[v] += constraint_weight[c];
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inc_score(v);
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// slack increasing var
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if (cur_solution[v] == constraint_term[c][j].sense)
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if (cur_solution[v] == is_pos(c[j]))
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inc_slack_score(v);
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}
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unsat(c);
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unsat(truep[i]);
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break;
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case 0: // from 1 to 0
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for (unsigned j = 0; j < constraint_term[c].size(); ++j) {
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v = constraint_term[c][j].var_id;
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for (unsigned j = 0; j < c.size(); ++j) {
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v = c[j].var();
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// flip the slack decreasing var will falsify this constraint
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if (cur_solution[v] != constraint_term[c][j].sense) {
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if (cur_solution[v] != is_pos(c[j])) {
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//score[v] -= constraint_weight[c];
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dec_score(v);
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dec_slack_score(v);
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@ -396,15 +388,15 @@ namespace sat {
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}
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}
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for (unsigned i = 0; i < falsep.size(); ++i) {
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c = falsep[i];
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constraint& c = m_constraints[falsep[i]];
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//--true_terms_count[c];
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++constraint_slack[c];
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switch (constraint_slack[c]) {
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++c.m_slack;
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switch (c.m_slack) {
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case 1: // from 0 to 1
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for (unsigned j = 0; j < constraint_term[c].size(); ++j) {
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v = constraint_term[c][j].var_id;
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for (unsigned j = 0; j < c.size(); ++j) {
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v = c[j].var();
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// flip the slack decreasing var will no long falsify this constraint
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if (cur_solution[v] != constraint_term[c][j].sense) {
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if (cur_solution[v] != is_pos(c[j])) {
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//score[v] += constraint_weight[c];
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inc_score(v);
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inc_slack_score(v);
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@ -412,22 +404,22 @@ namespace sat {
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}
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break;
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case 0: // from -1 to 0: unsat -> sat
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for (unsigned j = 0; j < constraint_term[c].size(); ++j) {
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v = constraint_term[c][j].var_id;
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++cscc[v];
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for (unsigned j = 0; j < c.size(); ++j) {
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v = c[j].var();
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inc_cscc(v);
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//score[v] -= constraint_weight[c];
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dec_score(v);
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// slack increasing var no longer sat this var
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if (cur_solution[v] == constraint_term[c][j].sense)
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if (cur_solution[v] == is_pos(c[j]))
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dec_slack_score(v);
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}
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sat(c);
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sat(falsep[i]);
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break;
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case -1: // from -2 to -1
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for (unsigned j = 0; j < constraint_term[c].size(); ++j) {
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v = constraint_term[c][j].var_id;
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for (unsigned j = 0; j < c.size(); ++j) {
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v = c[j].var();
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// flip the slack increasing var will satisfy this constraint
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if (cur_solution[v] == constraint_term[c][j].sense) {
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if (cur_solution[v] == is_pos(c[j])) {
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//score[v] += constraint_weight[c];
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inc_score(v);
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}
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@ -440,9 +432,8 @@ namespace sat {
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m_vars[flipvar].m_score = -org_flipvar_score;
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m_vars[flipvar].m_slack_score = -org_flipvar_slack_score;
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m_vars[flipvar].m_conf_change = false;
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cscc[flipvar] = 0;
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m_vars[flipvar].m_cscc = 0;
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/* update CCD */
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// remove the vars no longer goodvar in goodvar stack
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@ -483,7 +474,7 @@ namespace sat {
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((v_imp == b_imp) &&
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((conf_change(v) && !conf_change(best_var)) ||
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((conf_change(v) == conf_change(best_var)) &&
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(time_stamp[v] < time_stamp[best_var]))));
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(time_stamp(v) < time_stamp(best_var)))));
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}
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bool local_search::tie_breaker_ccd(bool_var v, bool_var best_var) {
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@ -496,13 +487,13 @@ namespace sat {
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((score(v) == score(best_var)) &&
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((slack_score(v) > slack_score(best_var)) ||
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((slack_score(v) == slack_score(best_var)) &&
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((cscc[v] > cscc[best_var]) ||
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((cscc[v] == cscc[best_var]) &&
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(time_stamp[v] < time_stamp[best_var])))))));
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((cscc(v) > cscc(best_var)) ||
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((cscc(v) == cscc(best_var)) &&
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(time_stamp(v) < time_stamp(best_var))))))));
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}
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bool_var local_search::pick_var() {
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int c, v;
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int v;
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bool_var best_var = 0;
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// SAT Mode
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@ -530,12 +521,12 @@ namespace sat {
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}
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// Diversification Mode
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c = m_unsat_stack[rand() % m_unsat_stack.size()]; // a random unsat constraint
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constraint const& c = m_constraints[m_unsat_stack[rand() % m_unsat_stack.size()]]; // a random unsat constraint
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// Within c, from all slack increasing var, choose the oldest one
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unsigned c_size = constraint_term[c].size();
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unsigned c_size = c.size();
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for (unsigned i = 0; i < c_size; ++i) {
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v = constraint_term[c][i].var_id;
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if (cur_solution[v] == constraint_term[c][i].sense && time_stamp[v] < time_stamp[best_var])
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v = c[i].var();
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if (cur_solution[v] == is_pos(c[i]) && time_stamp(v) < time_stamp(best_var))
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best_var = v;
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}
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return best_var;
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