mirrors/z3
3
0
Fork 0
mirror of https://github.com/Z3Prover/z3 synced 2025-08-05 19:00:25 +00:00
Code Activity

core opt

Browse source
This commit is contained in:
Nikolaj Bjorner 2022-05-21 10:27:32 -04:00
parent 127af83c53
commit 386c511f54
8 changed files with 182 additions and 56 deletions
Download patch file Download diff file Expand all files Collapse all files

53
src/opt/opt_preprocess.cpp
View file

@ -15,6 +15,19 @@ Author:
Nikolaj Bjorner (nbjorner) 2022-04-11
Notes:
maxsat x, y, z, u . x + y + z <= 1 and F
=>
maxsst x or y or z, u . x + y + z <= 1 and F
lower bound increased by 2
maxsat x, y, z, u . x + y + z >= 2 and F
=>
maxsst x and y and z, u . x + y + z >= 2 and F
lower bound decreased by 2
--*/
#pragma once
@ -113,13 +126,28 @@ namespace opt {
m_trail.push_back(sf.s);
if (new_soft.contains(sf.s))
new_soft[sf.s] += sf.weight;
else
else {
new_soft.insert(sf.s, sf.weight);
fmls.push_back(sf.s);
fmls.push_back(sf.s);
}
}
return new_soft;
}
obj_map<expr, rational> preprocess::dualize(obj_map<expr, rational> const& soft, expr_ref_vector& fmls) {
obj_map<expr, rational> new_soft;
for (auto const& [k, v] : soft) {
expr* nk = mk_not(m, k);
m_trail.push_back(nk);
new_soft.insert(nk, v);
}
unsigned i = 0;
for (expr* f : fmls)
fmls[i++] = mk_not(m, f);
return new_soft;
}
bool preprocess::find_mutexes(vector<soft>& softs, rational& lower) {
expr_ref_vector fmls(m);
obj_map<expr, rational> new_soft = soft2map(softs, fmls);
@ -131,6 +159,24 @@ namespace opt {
return false;
for (auto& mux : mutexes)
process_mutex(mux, new_soft, lower);
if (mutexes.empty())
{
obj_map<expr, rational> dual_soft = dualize(new_soft, fmls);
mutexes.reset();
lbool is_sat = s.find_mutexes(fmls, mutexes);
if (is_sat == l_false)
return true;
if (is_sat == l_undef)
return false;
rational llower(0);
for (auto& mux : mutexes)
process_mutex(mux, dual_soft, llower);
if (dual_soft.size() != new_soft.size())
new_soft = dualize(dual_soft, fmls);
}
softs.reset();
for (auto const& [k, v] : new_soft)
softs.push_back(soft(expr_ref(k, m), v, false));
@ -175,7 +221,7 @@ namespace opt {
weight = w - weight;
lower += weight*rational(i);
IF_VERBOSE(1, verbose_stream() << "(opt.maxsat mutex size: " << i + 1 << " weight: " << weight << ")\n";);
sum2 += weight*rational(i+1);
sum2 += weight * rational(i + 1);
new_soft.insert(soft, weight);
for (; i > 0 && weights[i-1] == w; --i) {}
weight = w;
@ -183,6 +229,7 @@ namespace opt {
SASSERT(sum1 == sum2);
}
preprocess::preprocess(solver& s): m(s.get_manager()), s(s), m_trail(m) {}
bool preprocess::operator()(vector<soft>& soft, rational& lower) {