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use lookahead for simplification

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2017-04-18 16:58:56 -07:00
parent 352f8b6cb9
commit a3f4d58b00
11 changed files with 183 additions and 45 deletions
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42
src/sat/sat_local_search.cpp
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@ -71,9 +71,8 @@ namespace sat {
void local_search::init_cur_solution() {
for (unsigned v = 0; v < num_vars(); ++v) {
// use bias with a small probability
if (m_rand() % 100 < 3) {
//m_vars[v].m_value = ((unsigned)(m_rand() % 100) < m_vars[v].m_bias);
m_vars[v].m_value = (50 < m_vars[v].m_bias);
if (m_rand() % 100 < 2) {
m_vars[v].m_value = ((unsigned)(m_rand() % 100) < m_vars[v].m_bias);
}
}
}
@ -138,20 +137,24 @@ namespace sat {
}
void local_search::reinit() {
// the following methods does NOT converge for pseudo-boolean
// can try other way to define "worse" and "better"
// the current best noise is below 1000
#if 0
if (m_best_unsat_rate > m_last_best_unsat_rate) {
// worse
m_noise -= m_noise * 2 * m_noise_delta;
m_best_unsat_rate *= 1000.0;
if (!m_is_pb) {
//
// the following methods does NOT converge for pseudo-boolean
// can try other way to define "worse" and "better"
// the current best noise is below 1000
//
if (m_best_unsat_rate > m_last_best_unsat_rate) {
// worse
m_noise -= m_noise * 2 * m_noise_delta;
m_best_unsat_rate *= 1000.0;
}
else {
// better
m_noise += (10000 - m_noise) * m_noise_delta;
}
}
else {
// better
m_noise += (10000 - m_noise) * m_noise_delta;
}
#endif
for (unsigned i = 0; i < m_constraints.size(); ++i) {
constraint& c = m_constraints[i];
c.m_slack = c.m_k;
@ -264,7 +267,7 @@ namespace sat {
unsigned id = m_constraints.size();
m_constraints.push_back(constraint(k));
for (unsigned i = 0; i < sz; ++i) {
m_vars.reserve(c[i].var() + 1);
m_vars.reserve(c[i].var() + 1);
literal t(~c[i]);
m_vars[t.var()].m_watch[is_pos(t)].push_back(pbcoeff(id, coeffs[i]));
m_constraints.back().push(t); // add coefficient to constraint?
@ -279,6 +282,7 @@ namespace sat {
}
void local_search::import(solver& s, bool _init) {
m_is_pb = false;
m_vars.reset();
m_constraints.reset();
@ -349,6 +353,7 @@ namespace sat {
// = ~c.lit() or (~c.lits() <= n - k)
// = k*c.lit() + ~c.lits() <= n
//
m_is_pb = true;
lits.reset();
coeffs.reset();
for (unsigned j = 0; j < n; ++j) lits.push_back(c[j]), coeffs.push_back(1);
@ -616,8 +621,7 @@ namespace sat {
// verify_unsat_stack();
}
void local_search::flip_gsat(bool_var flipvar)
{
void local_search::flip_gsat(bool_var flipvar) {
// already changed truth value!!!!
m_vars[flipvar].m_value = !cur_solution(flipvar);