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fixing local search

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2018-03-15 06:48:26 -07:00
parent bf8ea92b99
commit 59b142f803
11 changed files with 107 additions and 57 deletions
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52
src/sat/sat_local_search.cpp
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@ -34,8 +34,13 @@ namespace sat {
// add sentinel variable.
m_vars.push_back(var_info());
for (unsigned v = 0; v < num_vars(); ++v) {
m_vars[v].m_value = (0 == (m_rand() % 2));
if (m_config.phase_sticky()) {
for (var_info& vi : m_vars)
vi.m_value = vi.m_bias < 100;
}
else {
for (var_info& vi : m_vars)
vi.m_value = (0 == (m_rand() % 2));
}
m_best_solution.resize(num_vars() + 1, false);
@ -70,13 +75,14 @@ namespace sat {
}
void local_search::init_cur_solution() {
for (unsigned v = 0; v < num_vars(); ++v) {
IF_VERBOSE(1, verbose_stream() << "(sat.local_search init-cur-solution)\n");
for (var_info& vi : m_vars) {
// use bias with a small probability
if (m_rand() % 10 < 5) {
m_vars[v].m_value = ((unsigned)(m_rand() % 100) < m_vars[v].m_bias);
if (m_rand() % 10 < 5 || m_config.phase_sticky()) {
vi.m_value = ((unsigned)(m_rand() % 100) < vi.m_bias);
}
else {
m_vars[v].m_value = (m_rand() % 2) == 0;
vi.m_value = (m_rand() % 2) == 0;
}
}
}
@ -189,8 +195,15 @@ namespace sat {
init_slack();
init_scores();
init_goodvars();
set_best_unsat();
}
void local_search::set_best_unsat() {
m_best_unsat = m_unsat_stack.size();
if (m_best_unsat == 1) {
constraint const& c = m_constraints[m_unsat_stack[0]];
IF_VERBOSE(2, display(verbose_stream() << "single unsat:", c));
}
}
void local_search::calculate_and_update_ob() {
@ -275,7 +288,9 @@ namespace sat {
m_constraints.back().push(t);
}
if (sz == 1 && k == 0) {
m_vars[c[0].var()].m_bias = c[0].sign() ? 0 : 100;
literal lit = c[0];
m_vars[lit.var()].m_bias = lit.sign() ? 100 : 0;
m_vars[lit.var()].m_value = lit.sign();
}
}
@ -289,8 +304,10 @@ namespace sat {
m_vars[t.var()].m_watch[is_pos(t)].push_back(pbcoeff(id, coeffs[i]));
m_constraints.back().push(t);
}
if (sz == 1 && k == 0) {
m_vars[c[0].var()].m_bias = c[0].sign() ? 0 : 100;
if (sz == 1 && k == 0) {
literal lit = c[0];
m_vars[lit.var()].m_bias = lit.sign() ? 100 : 0;
m_vars[lit.var()].m_value = lit.sign();
}
}
@ -304,6 +321,14 @@ namespace sat {
m_constraints.reset();
m_vars.reserve(s.num_vars());
if (m_config.phase_sticky()) {
unsigned v = 0;
for (var_info& vi : m_vars) {
if (vi.m_bias != 0 && vi.m_bias != 100)
vi.m_bias = s.m_phase[v] == POS_PHASE ? 100 : 0;
++v;
}
}
// copy units
unsigned trail_sz = s.init_trail_size();
@ -462,7 +487,7 @@ namespace sat {
for (step = 0; step < m_max_steps && !m_unsat_stack.empty(); ++step) {
pick_flip_walksat();
if (m_unsat_stack.size() < m_best_unsat) {
m_best_unsat = m_unsat_stack.size();
set_best_unsat();
m_last_best_unsat_rate = m_best_unsat_rate;
m_best_unsat_rate = (double)m_unsat_stack.size() / num_constraints();
}
@ -497,7 +522,7 @@ namespace sat {
}
}
if (m_unsat_stack.size() < m_best_unsat) {
m_best_unsat = m_unsat_stack.size();
set_best_unsat();
}
flipvar = pick_var_gsat();
flip_gsat(flipvar);
@ -876,10 +901,7 @@ namespace sat {
}
void local_search::set_parameters() {
SASSERT(s_id == 0);
m_rand.set_seed(m_config.seed());
//srand(m_config.seed());
s_id = m_config.strategy_id();
m_rand.set_seed(m_config.random_seed());
m_best_known_value = m_config.best_known_value();
switch (m_config.mode()) {