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forbidden intervals for strict inequalities

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2022-01-22 11:14:53 +01:00
parent 82798863ba
commit 417a5320c7
5 changed files with 95 additions and 19 deletions
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65
src/math/polysat/forbidden_intervals.cpp
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@ -52,12 +52,24 @@ namespace polysat {
// We keep the e1, e2 around in case we need side conditions such as e1=b1, e2=b2.
auto [ok1, a1, e1, b1] = linear_decompose(v, c->to_ule().lhs(), fi.side_cond);
auto [ok2, a2, e2, b2] = linear_decompose(v, c->to_ule().rhs(), fi.side_cond);
if (!ok1 || !ok2 || (a1.is_zero() && a2.is_zero()))
_backtrack.released = true;
// v > q
if (ok1 && !ok2 && match_non_zero(c, a1, b1, e1, fi))
return true;
// p > v
if (!ok1 && ok2 && match_non_max(c, a2, b2, e2, fi))
return true;
if (!ok1 || !ok2 || (a1.is_zero() && a2.is_zero())) {
_backtrack.released = false;
return false;
}
SASSERT(b1.is_val());
SASSERT(b2.is_val());
_backtrack.released = true;
if (match_linear1(c, a1, b1, e1, a2, b2, e2, fi))
return true;
@ -250,6 +262,55 @@ namespace polysat {
return false;
}
/**
* v > q
* forbidden interval for v is [0,1[
*
* Generalizations todo:
*
* v - k > q
* forbidden interval for v is [k,k+1[
*
* a*v - k > q, a odd
* forbidden interval for v is [a^-1*k, a^-1*k + 1[
*/
bool forbidden_intervals::match_non_zero(
signed_constraint const& c,
rational const & a1, pdd const& b1, pdd const& e1,
fi_record& fi) {
if (a1.is_odd() && b1.is_zero() && !c.is_positive()) {
auto& m = e1.manager();
rational lo_val(0);
auto lo = m.zero();
rational hi_val(1);
auto hi = m.one();
fi.coeff = 1;
fi.interval = eval_interval::proper(lo, lo_val, hi, hi_val);
if (b1 != e1)
fi.side_cond.push_back(s.eq(b1, e1));
return true;
}
return false;
}
/**
* p > v
* forbidden interval for v is [-1,0[
* p > v + k
* forbidden interval for v is [-k-1,-k[
*/
bool forbidden_intervals::match_non_max(
signed_constraint const& c,
rational const & a2, pdd const& b2, pdd const& e2,
fi_record& fi) {
if (a2.is_one() && b2.is_zero() && !c.is_positive()) {
// todo
}
return false;
}
void forbidden_intervals::add_non_unit_side_conds(fi_record& fi, pdd const& b1, pdd const& e1, pdd const& b2, pdd const& e2) {
if (fi.coeff == 1)
return;