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variations on unit-walk

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2019-02-13 17:43:15 -08:00
parent 83f0fd5cc2
commit 5cdfa7cd1c
9 changed files with 163 additions and 154 deletions
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30
src/sat/sat_local_search.cpp
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@ -591,18 +591,40 @@ namespace sat {
m_unsat_stack.push_back(c);
}
void local_search::pick_flip_lookahead() {
unsigned num_unsat = m_unsat_stack.size();
constraint const& c = m_constraints[m_unsat_stack[m_rand() % num_unsat]];
literal best = null_literal;
unsigned best_make = UINT_MAX;
for (literal lit : c.m_literals) {
if (!is_unit(lit) && is_true(lit)) {
flip_walksat(lit.var());
if (propagate(~lit) && best_make > m_unsat_stack.size()) {
best = lit;
best_make = m_unsat_stack.size();
}
flip_walksat(lit.var());
propagate(lit);
}
}
if (best != null_literal) {
flip_walksat(best.var());
propagate(~best);
}
else {
std::cout << "no best\n";
}
}
void local_search::pick_flip_walksat() {
reflip:
bool_var best_var = null_bool_var;
unsigned n = 1;
bool_var v = null_bool_var;
unsigned num_unsat = m_unsat_stack.size();
constraint const& c = m_constraints[m_unsat_stack[m_rand() % m_unsat_stack.size()]];
// VERIFY(c.m_k < constraint_value(c));
constraint const& c = m_constraints[m_unsat_stack[m_rand() % num_unsat]];
unsigned reflipped = 0;
bool is_core = m_unsat_stack.size() <= 10;
// TBD: dynamic noise strategy
//if (m_rand() % 100 < 98) {
if (m_rand() % 10000 <= m_noise) {
// take this branch with 98% probability.
// find the first one, to fast break the rest