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Begin reorganizing resolve_value

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Jakob Rath 2021-09-07 11:40:50 +02:00
parent b4e14c31d0
commit 7d58296ad2
6 changed files with 113 additions and 25 deletions
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28
src/math/polysat/solver.cpp
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@ -526,31 +526,11 @@ namespace polysat {
}
// Value Resolution
// TODO: maybe don't do this automatically, because cjust-constraints are true and core constraints are false.
// issue: what if viable(v) is empty? then we only have cjust constraints and none of them is evaluable (at least not immediately because no value is set for this variable.)
// => think about what we want to do in this case (choose a value and evaluate? try all possible superpositions without caring about the value of the premises?)
// the last value_resolution method can then be the one that adds the cjusts and calls saturation and more general VE.
for (auto c : m_cjust[v])
m_conflict.insert(c);
// Variable elimination
while (true) {
// TODO:
// 1. Try variable elimination of 'v'
// 2. If not possible, try saturation and core reduction (actually reduction could be one specific VE method?).
// 3. as a last resort, substitute v by m_value[v]?
// TODO: maybe we shouldn't try to split up VE/Saturation in the implementation.
// it might be better to just have more general "core inferences" that may combine elimination/saturation steps that fit together...
// or even keep the whole "value resolution + VE/Saturation" as a single step. we might want to know which constraints come from the current cjusts?
if (m_conflict.try_eliminate(v))
return;
if (!m_conflict.try_saturate(v))
break;
if (!m_conflict.resolve_value(v, m_cjust[v])) {
// Failed to resolve => bail out
++m_stats.m_num_bailouts;
m_conflict.set_bailout();
}
// Failed to resolve => bail out
++m_stats.m_num_bailouts;
m_conflict.set_bailout();
}
/** Conflict resolution case where boolean literal 'lit' is on top of the stack */