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First version of refine_disequal_lin

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This commit is contained in:
Jakob Rath 2021-12-23 18:36:27 +01:00
parent eb9bfbb3d8
commit 28864e563c
5 changed files with 103 additions and 8 deletions
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63
src/math/polysat/viable.cpp
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@ -276,7 +276,67 @@ namespace polysat {
auto* e = m_diseq_lin[v];
if (!e)
return true;
LOG("refine-disequal-lin is TBD");
entry* first = e;
rational const& max_value = s.var2pdd(v).max_value();
rational mod_value = max_value + 1;
do {
LOG("refine-disequal-lin for src: " << e->src);
// We have:
// a1*v + b1 > a2*v + b2 if e->src.is_positive()
// a1*v + b1 >= a2*v + b2 if e->src.is_negative()
// Note that e->interval is meaningless in this case,
// we just use it to transport the values a1,b1,a2,b2.
rational const& a1 = e->interval.lo_val();
rational const& b1 = e->interval.lo().val();
rational const& a2 = e->interval.hi_val();
rational const& b2 = e->interval.hi().val();
rational lhs = a1 * val + b1;
rational rhs = a2 * val + b2;
auto delta_l = [&](rational const& val) {
rational m1 = ceil((rhs + 1) / a2);
int corr = e->src.is_negative() ? 1 : 0;
rational m3 = (lhs - rhs + corr) / (a1 - a2);
if (m3 <= 0)
m3 = m1; // remove m3 from the minimum
return std::min(m1, m3) - 1;
};
auto delta_u = [&](rational const& val) {
rational m1 = ceil((mod_value - lhs) / a1);
rational m2 = mod_value - val;
int corr = e->src.is_negative() ? 1 : 0;
rational m3 = (lhs - rhs + corr) / (a2 - a1);
if (m3 <= 0)
m3 = m2; // remove m3 from the minimum
return std::min(m1, std::min(m2, m3)) - 1;
};
if (lhs > rhs || (e->src.is_negative() && lhs == rhs)) {
rational lo = val - delta_l(val);
rational hi = val + delta_u(val) + 1;
// TODO: increase interval
LOG("refine-disequal-lin: " << " [" << lo << ", " << hi << "[");
// SASSERT(false);
SASSERT(0 <= lo);
SASSERT(hi <= max_value);
pdd lop = s.var2pdd(v).mk_val(lo);
pdd hip = s.var2pdd(v).mk_val(hi);
entry* ne = alloc_entry();
ne->src = e->src;
ne->side_cond = e->side_cond;
ne->coeff = 1;
ne->interval = eval_interval::proper(lop, lo, hip, hi);
intersect(v, ne);
return false;
}
e = e->next();
}
while (e != first);
return true;
}
@ -313,6 +373,7 @@ namespace polysat {
}
while (e != first);
return false;
#undef CHECK_RETURN
}
bool viable::is_viable(pvar v, rational const& val) {