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if you are really reading this commit message, you must be a programmer who has no life.

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Nikolaj Bjorner 2021-11-18 10:10:50 -08:00
parent a5fdf6ba8a
commit de424713e4
6 changed files with 33 additions and 16 deletions
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27
src/math/polysat/solver.cpp
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@ -125,13 +125,15 @@ namespace polysat {
m_constraints.ensure_bvar(c.get());
sat::literal lit = c.blit();
LOG("New constraint: " << c);
if (m_bvars.is_false(lit) || c.is_currently_false(*this)) {
set_conflict(c /*, dep */);
return;
if (m_bvars.is_false(lit))
set_conflict(c);
else {
m_bvars.asserted(lit, m_level, dep);
m_trail.push_back(trail_instr_t::assign_bool_i);
m_search.push_boolean(lit);
if (c.is_currently_false(*this))
set_conflict(c);
}
m_bvars.asserted(lit, m_level, dep);
m_trail.push_back(trail_instr_t::assign_bool_i);
m_search.push_boolean(lit);
#if ENABLE_LINEAR_SOLVER
m_linear_solver.new_constraint(*c.get());
@ -577,6 +579,13 @@ namespace polysat {
/**
* Revert a decision that caused a conflict.
* Variable v was assigned by a decision at position i in the search stack.
*
* C & v = val is conflict.
*
* C => v != val
*
* l1 \/ l2 \/ ... \/ lk \/ v != val
*
*/
void solver::revert_decision(pvar v) {
rational val = m_value[v];
@ -594,7 +603,11 @@ namespace polysat {
// The justification for this restriction is the guessed constraint from the lemma.
// cjust[v] will be updated accordingly by decide_bool.
m_viable.add_non_viable(v, val);
// m_viable.add_non_viable(v, val);
// TBD: review with Jakob: add_non_viable seems redundant. The lemma contains the disjunction that v != val
// other literals in the lemma could be chosen, but they prune decisions further down.
// when the v != val literal is selected the viability constraint gets asserted.
learn_lemma(v, *lemma);
if (!is_conflict())