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Added missing minimality lemma for pseudo_inverse

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Clemens Eisenhofer 2023-01-15 12:11:15 +01:00
parent caf624589e
commit b33911de13
1 changed files with 10 additions and 8 deletions
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18
src/math/polysat/op_constraint.cpp
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@ -640,9 +640,8 @@ namespace polysat {
return s.mk_clause(~invc, ~s.eq(r()), s.eq(p()), true);
// p assigned => r = pseudo_inverse(eval(p))
if (pv.is_val() && !rv.is_val()) {
if (pv.is_val() && !rv.is_val())
return s.mk_clause(~invc, ~s.eq(p(), pv), s.eq(r(), pv.val().pseudo_inverse(m.power_of_2())), true);
}
if (!pv.is_val() || !rv.is_val())
return {};
@ -659,21 +658,24 @@ namespace polysat {
rational prodv = (pv * rv).val();
SASSERT(prodv != rational::power_of_two(parity_pv)); // Why did it evaluate to false in this case?
unsigned lower = 0, upper = p().power_of_2();
// binary search for the parity
// binary search for the parity (otw. we would have justifications like "parity_at_most(k) && parity_at_least(k)" for at most "k" widths
while (lower + 1 < upper) {
unsigned middle = (upper + lower) / 2;
LOG("Splitting on " << middle);
if (parity_pv >= middle) {
if (parity_pv >= middle) { // parity at least middle
lower = middle;
LOG("Its in [" << lower << "; " << upper << ")");
if (prodv < rational::power_of_two(middle))
if (prodv < rational::power_of_two(middle)) // product is for sure not 2^parity
return s.mk_clause(~invc, ~s.parity_at_least(p(), middle), s.uge(prod, rational::power_of_two(middle)), false);
}
else {
else { // parity at most middle
upper = middle;
LOG("Its in [" << lower << "; " << upper << ")");
if (prodv >= rational::power_of_two(middle))
return s.mk_clause(~invc, s.parity_at_least(p(), middle), s.ult(prod, rational::power_of_two(middle)), false);
if (prodv > rational::power_of_two(middle)) // product is for sure not 2^parity
return s.mk_clause(~invc, s.parity_at_least(p(), middle), s.ule(prod, rational::power_of_two(middle)), false);
if (rv.val() >= rational::power_of_two(p().power_of_2() - middle)) // enforce that pseudo-inverse is smaller than 2^k-parity (minimal pseudo-inverse)
return s.mk_clause(~invc, s.parity_at_least(p(), middle), s.ule(r(), rational::power_of_two(p().power_of_2() - middle) - 1), false);
}
}
UNREACHABLE();