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very basic refinement loop breaking

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This commit is contained in:
Jakob Rath 2022-12-15 13:39:48 +01:00
parent 3d06a90e7f
commit 5de0007157
3 changed files with 158 additions and 26 deletions
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23
src/math/polysat/solver.cpp
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@ -647,22 +647,29 @@ namespace polysat {
rational val;
justification j;
switch (m_viable.find_viable(v, val)) {
case dd::find_t::empty:
case find_t::empty:
// NOTE: all such cases should be discovered elsewhere (e.g., during propagation/narrowing)
// (fail here in debug mode so we notice if we miss some)
DEBUG_CODE( UNREACHABLE(); );
m_free_pvars.unassign_var_eh(v);
set_conflict(v, false);
return;
case dd::find_t::singleton:
case find_t::singleton:
// NOTE: this case may happen legitimately if all other possibilities were excluded by brute force search
// NOTE 2: probably not true anymore; viable::intersect should trigger all propagations now
DEBUG_CODE( UNREACHABLE(); );
j = justification::propagation(m_level);
break;
case dd::find_t::multiple:
case find_t::multiple:
j = justification::decision(m_level + 1);
break;
case find_t::resource_out:
// the value is not viable, so assign_verify will call the univariate solver.
j = justification::decision(m_level + 1);
break;
default:
UNREACHABLE();
break;
}
assign_verify(v, val, j);
}
@ -731,20 +738,24 @@ namespace polysat {
}
if (c) {
LOG_H2("Chosen assignment " << assignment_pp(*this, v, val) << " is not actually viable!");
LOG("Current assignment: " << assignments_pp(*this));
++m_stats.m_num_viable_fallback;
// Try to find a valid replacement value
switch (m_viable_fallback.find_viable(v, val)) {
case dd::find_t::singleton:
case dd::find_t::multiple:
case find_t::singleton:
case find_t::multiple:
LOG("Fallback solver: " << assignment_pp(*this, v, val));
SASSERT(!j.is_propagation()); // all excluded values are true negatives, so if j.is_propagation() the univariate solver must return unsat
j = justification::decision(m_level + 1);
break;
case dd::find_t::empty:
case find_t::empty:
LOG("Fallback solver: unsat");
m_free_pvars.unassign_var_eh(v);
set_conflict(v, true);
return;
case find_t::resource_out:
UNREACHABLE(); // TODO: abort solving
return;
}
}
if (j.is_decision())