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add facility to support propagation

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This commit is contained in:
Nikolaj Bjorner 2024-01-06 16:26:03 -08:00
parent 30c0771d24
commit 11c529162d
2 changed files with 47 additions and 10 deletions
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54
src/sat/smt/polysat/viable.cpp
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@ -89,7 +89,8 @@ namespace polysat {
m_num_bits = c.size(v);
m_fixed_bits.init(v);
init_overlaps(v);
m_conflict = false;
m_conflict = false;
m_propagation = false;
// verbose_stream() << "find viable v" << v << " starting with " << lo << "\n";
@ -100,13 +101,21 @@ namespace polysat {
if (m_conflict)
return find_t::empty;
if (!n) {
if (check_fixed_bits(v, lo) &&
check_disequal_lin(v, lo) &&
check_equal_lin(v, lo))
return find_t::multiple;
++rounds;
}
if (n)
continue;
++rounds;
if (!check_fixed_bits(v, lo))
continue;
if (!check_disequal_lin(v, lo))
continue;
if (!check_equal_lin(v, lo))
continue;
if (is_propagation(lo)) {
m_propagation = true;
return find_t::singleton;
}
return find_t::multiple;
}
return find_t::resource_out;
@ -487,13 +496,29 @@ namespace polysat {
return false;
}
bool viable::is_propagation(rational const& val) {
// disable for now
return false;
if (m_explain.empty())
return false;
auto last = m_explain.back();
auto first = m_explain[0];
if (first.e->interval.lo_val() == val + 1 &&
last.e->interval.hi_val() == val &&
first.e->bit_width == last.e->bit_width &&
first.e->bit_width == c.size(m_var)) {
return true;
}
return false;
}
/*
* Explain why the current variable is not viable or
* or why it can only have a single value.
*/
dependency_vector viable::explain() {
dependency_vector result;
SASSERT(is_conflict());
uint_set seen;
auto last = m_explain.back();
auto after = last;
@ -511,6 +536,7 @@ namespace polysat {
SASSERT(m_explain.size() == 1);
}
SASSERT(m_conflict || m_propagation);
for (unsigned i = m_explain.size() - 1; i-- > 0; ) {
auto e = m_explain[i];
auto index = e.e->constraint_index;
@ -529,6 +555,16 @@ namespace polysat {
result.push_back(c.get_dependency(index));
if (e.e == last.e)
break;
}
if (m_propagation) {
NOT_IMPLEMENTED_YET();
auto first = m_explain[0];
// add constraint that:
auto sc = cs.eq(last.e->interval.hi() + 1, first.e->interval.lo());
result.push_back(c.propagate(sc, c.explain_weak_eval(sc)));
// assume first and last have same bit-width
}
return result;
}

3
src/sat/smt/polysat/viable.h
View file

@ -134,10 +134,11 @@ namespace polysat {
bool check_fixed_bits(pvar v, rational const& val);
bool is_propagation(rational const& val);
pvar m_var = null_var;
bool m_conflict = false;
bool m_propagation = false;
unsigned m_num_bits = 0;
fixed_bits m_fixed_bits;
offset_slices m_overlaps;