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review comments by Elffers

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2019-07-21 06:52:02 -07:00
parent e593b5b2c8
commit a9a26e5f2e
4 changed files with 54 additions and 2 deletions
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7
src/sat/ba_solver.cpp
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@ -1400,6 +1400,12 @@ namespace sat {
unsigned ci = ineq.coeff(i);
unsigned q = ci % c;
if (q != 0 && !is_false(ineq.lit(i))) {
#if 1
// code review by Elffers:
ineq.weaken(i);
--i;
--sz;
#else
if (q == ci) {
ineq.weaken(i);
--i;
@ -1409,6 +1415,7 @@ namespace sat {
ineq.m_wlits[i].first -= q;
ineq.m_k -= q;
}
#endif
}
}
ineq.divide(c);

1
src/sat/sat_params.pyg
View file

@ -48,6 +48,7 @@ def_module_params('sat',
('drat.check_sat', BOOL, False, 'build up internal trace, check satisfying model'),
('cardinality.solver', BOOL, True, 'use cardinality solver'),
('pb.solver', SYMBOL, 'solver', 'method for handling Pseudo-Boolean constraints: circuit (arithmetical circuit), sorting (sorting circuit), totalizer (use totalizer encoding), binary_merge, segmented, solver (use native solver)'),
('pb.min_arity', UINT, 9, 'minimal arity to compile pb/cardinality constraints to CNF'),
('xor.solver', BOOL, False, 'use xor solver'),
('cardinality.encoding', SYMBOL, 'grouped', 'encoding used for at-most-k constraints: grouped, bimander, ordered, unate, circuit'),
('pb.resolve', SYMBOL, 'cardinality', 'resolution strategy for boolean algebra solver: cardinality, rounding'),

34
src/sat/sat_solver.cpp
View file

@ -3161,12 +3161,42 @@ namespace sat {
m_activity_inc = 128;
svector<bool_var> vars;
for (bool_var v = num_vars(); v-- > 0; ) {
vars.push_back(v);
if (!was_eliminated(v) && value(v) == l_undef) {
vars.push_back(v);
}
}
#if 1
//
// exp(logits[i]) / sum(exp(logits))
// =
// exp(log(exp(logits[i]) / sum(exp(logits))))
// =
// exp(log(exp(logits[i])) - log(sum(exp(logits))))
// =
// exp(logits[i] - lse)
svector<float> logits(vars.size(), 0.0);
float itau = 4.0;
float lse = 0;
float mid = m_rand.max_value()/2;
float max = 0;
for (float& f : logits) {
f = itau * (m_rand() - mid)/mid;
if (f > max) max = f;
}
for (float f : logits) {
lse += log(f - max);
}
lse = max + exp(lse);
for (unsigned i = 0; i < vars.size(); ++i) {
update_activity(vars[i], exp(logits[i] - lse));
}
#else
shuffle(vars.size(), vars.c_ptr(), m_rand);
for (bool_var v : vars) {
update_activity(v, m_rand(10));
update_activity(v, m_rand(10)/10.0);
}
#endif
m_reorder_inc += m_config.m_reorder_base;
m_reorder_lim += m_reorder_inc;
}