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interval conflict fixes

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This commit is contained in:
Jakob Rath 2023-12-22 11:01:23 +01:00
parent c6ee5b76ad
commit 4dc77036a6
1 changed files with 19 additions and 4 deletions
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23
src/math/polysat/viable.cpp
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@ -1952,6 +1952,7 @@ namespace polysat {
}
bool viable::set_conflict_by_interval(pvar v, unsigned w, ptr_vector<entry>& intervals, unsigned first_interval) {
LOG_H2("interval conflict: v" << v << " at width " << w << " with " << (intervals.size() - first_interval) << " intervals");
SASSERT(!intervals.empty());
SASSERT(first_interval < intervals.size());
auto& core = s.m_conflict;
@ -2011,6 +2012,12 @@ namespace polysat {
bool viable::set_conflict_by_interval_rec(pvar v, unsigned w, entry** intervals, unsigned num_intervals, conflict& core, bool& create_lemma, clause_builder& lemma, uint_set& vars_to_explain) {
// LOG_H3("interval conflict rec: v" << v << " at width " << w << " with " << num_intervals << " intervals");
// for (unsigned ii = 0; ii < num_intervals; ++ii) {
// entry* ee = intervals[ii];
// display_one(std::cerr << " entry " << ii << ": width=" << ee->bit_width << " ", ee->var, ee) << "\n";
// }
SASSERT(std::all_of(intervals, intervals + num_intervals, [w](entry const* e) { return e->bit_width <= w; }));
// TODO: assert invariants on intervals list
rational const& mod_value = rational::power_of_two(w);
@ -2050,6 +2057,7 @@ namespace polysat {
if (n->bit_width != w) {
// we have a hole starting with 'n', to be filled with intervals at lower bit-width.
// note that the next lower bit-width is not necessarily n->bit_width (e.g., the next layer may start with a hole itself)
// e.g. if bit-widths are: [64, 64, 16, 16, 32, 32, 64]
unsigned w2 = n->bit_width;
// first, find the next constraint after the hole
unsigned last_idx = j;
@ -2059,16 +2067,22 @@ namespace polysat {
w2 = intervals[k]->bit_width;
last_idx = k;
k = (k + 1) % num_intervals;
// by construction of the interval list, the hole cannot wrap around.
// we need to break out of the loop when k == 0, in case there was also a hole at the start of the intervals list.
if (k == 0)
break;
}
entry* after = intervals[k];
SASSERT(j < last_idx); // the hole cannot wrap around (but k may be 0)
SASSERT(j <= last_idx); // the hole cannot wrap around, by construction of the interval list (but k may be 0)
rational const& lower_mod_value = rational::power_of_two(w2);
SASSERT(distance(e->interval.hi_val(), after->interval.lo_val(), mod_value) < lower_mod_value); // otherwise we would have started the conflict at w2 already
// create temporary entry that covers the hole-complement on the lower level
if (!tmp)
if (!tmp) {
tmp = alloc_entry(v);
tmp->coeff = 1;
}
pdd dummy = s.var2pdd(v).mk_val(123); // we could create extract-terms for boundaries but let's skip that for now and just disable the lemma
create_lemma = false;
tmp->valid_for_lemma = false;
@ -2103,11 +2117,12 @@ namespace polysat {
tmp->bit_width = w;
tmp->interval = eval_interval::proper(dummy, e->interval.hi_val(), dummy, after->interval.lo_val());
i = last_idx;
e = tmp;
j = k;
n = after;
continue;
}
SASSERT_EQ(n->bit_width, w);
// We may have a bunch of intervals that contain the current value.
// Choose the one making the most progress.
// TODO: it should be the last one, otherwise we wouldn't have added it to relevant_intervals? then we can skip the progress computation.