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Strengthen forbidden_intervals::match_non_zero

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This commit is contained in:
Jakob Rath 2022-12-22 16:30:23 +01:00
parent 21ea05b31c
commit e57bcdfeab
1 changed files with 28 additions and 4 deletions
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26
src/math/polysat/forbidden_intervals.cpp
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@ -432,14 +432,35 @@ namespace polysat {
* v - k > q * v - k > q
* forbidden interval for v is [k,k+1[ * forbidden interval for v is [k,k+1[
* *
* v > q
* forbidden interval for v is [0;q+1[ but at least [0;1[
*
* The following cases are implemented, and subsume the simple ones above.
*
* v - k > q
* forbidden interval for v is [k;k+q+1[ but at least [k;k+1[
*
* a*v - k > q, a odd * a*v - k > q, a odd
* forbidden interval for v is [a^-1*k, a^-1*k + 1[ * forbidden interval for v is [a^-1*k, a^-1*k + 1[
*/ */
bool forbidden_intervals::match_non_zero( bool forbidden_intervals::match_non_zero(
signed_constraint const& c, signed_constraint const& c,
rational const & a1, pdd const& b1, pdd const& e1, rational const& a1, pdd const& b1, pdd const& e1,
pdd const& q,
fi_record& fi) { fi_record& fi) {
_last_function = __func__; _last_function = __func__;
if (a1.is_one() && b1.is_val() && c.is_negative()) {
auto& m = e1.manager();
rational const& mod_value = m.two_to_N();
rational lo_val = (-b1).val();
pdd lo = -e1;
rational hi_val = mod(lo_val + 1, mod_value);
pdd hi = lo + q + 1;
fi.coeff = 1;
fi.interval = eval_interval::proper(lo, lo_val, hi, hi_val);
return true;
}
#if 0 // this case is subsumed by the next one, which even creates stronger intervals
if (a1.is_odd() && b1.is_zero() && c.is_negative()) { if (a1.is_odd() && b1.is_zero() && c.is_negative()) {
auto& m = e1.manager(); auto& m = e1.manager();
rational lo_val(0); rational lo_val(0);
@ -452,6 +473,7 @@ namespace polysat {
fi.side_cond.push_back(s.eq(b1, e1)); fi.side_cond.push_back(s.eq(b1, e1));
return true; return true;
} }
#endif
if (a1.is_odd() && b1.is_val() && c.is_negative()) { if (a1.is_odd() && b1.is_val() && c.is_negative()) {
auto& m = e1.manager(); auto& m = e1.manager();
rational const& mod_value = m.two_to_N(); rational const& mod_value = m.two_to_N();
@ -463,8 +485,10 @@ namespace polysat {
auto hi = lo + 1; auto hi = lo + 1;
fi.coeff = 1; fi.coeff = 1;
fi.interval = eval_interval::proper(lo, lo_val, hi, hi_val); fi.interval = eval_interval::proper(lo, lo_val, hi, hi_val);
#if 0 // side condition is not needed because we use e1 in the symbolic bounds
if (b1 != e1) if (b1 != e1)
fi.side_cond.push_back(s.eq(b1, e1)); fi.side_cond.push_back(s.eq(b1, e1));
#endif
return true; return true;
} }
return false; return false;