mirrors/z3
3
0
Fork 0
mirror of https://github.com/Z3Prover/z3 synced 2025-08-25 20:46:01 +00:00
Code Activity

reorganize variable tracking for lemmas

Browse source 
this is going to break a bunch
This commit is contained in:
Nikolaj Bjorner 2021-09-12 18:05:29 +02:00
parent deeb6c7784
commit f5fd295e01
9 changed files with 191 additions and 136 deletions
Download patch file Download diff file Expand all files Collapse all files

27
src/math/polysat/conflict_core.h
View file

@ -25,18 +25,29 @@ namespace polysat {
/** Conflict state, represented as core (~negation of clause). */
class conflict_core {
vector<signed_constraint> m_constraints;
vector<signed_constraint> m_constraints; // constraints used as premises
uint_set m_vars; // variable assignments used as premises
// If this is not null_var, the conflict was due to empty viable set for this variable.
// Can be treated like "v = x" for any value x.
pvar m_conflict_var = null_var;
/** True iff the conflict depends on the current variable assignment. (If so, additional constraints must be added to the final learned clause.) */
bool m_needs_model = false;
// NOTE: for now we keep this simple implementation.
// The drawback is that we may get weaker lemmas in some cases (but they are still correct).
// For example: if we have 4x+y=2 and y=0, then we have a conflict no matter the value of x, so we should drop x=? from the core.
unsigned_vector m_pvar2count; // reference count of variables
void inc_pref(pvar v);
void dec_pref(pvar v);
bool_vector m_bvar2mark; // mark of Boolean variables
void set_bmark(sat::bool_var b);
void unset_bmark(sat::bool_var b);
void set_mark(constraint* c);
void unset_mark(constraint* c);
/** Whether we are in a bailout state. We enter a bailout state when we give up on proper conflict resolution. */
bool m_bailout = false;
std::optional<clause_builder> m_bailout_lemma;
@ -56,19 +67,20 @@ namespace polysat {
~conflict_core();
vector<signed_constraint> const& constraints() const { return m_constraints; }
bool needs_model() const { return m_needs_model; }
pvar conflict_var() const { return m_conflict_var; }
bool is_bailout() const { return m_bailout; }
void set_bailout() { SASSERT(!is_bailout()); m_bailout = true; }
bool empty() const {
return m_constraints.empty() && !m_needs_model && m_conflict_var == null_var;
return m_constraints.empty() && m_vars.empty() && conflict_var() == null_var;
}
void reset() {
for (auto c : m_constraints)
unset_mark(c.get());
m_constraints.reset();
m_needs_model = false;
m_vars.reset();
m_conflict_var = null_var;
m_saturation_premises.reset();
m_bailout = false;
@ -76,6 +88,9 @@ namespace polysat {
SASSERT(empty());
}
bool is_pmarked(pvar v) const;
bool is_bmarked(sat::bool_var b) const;
/** conflict because the constraint c is false under current variable assignment */
void set(signed_constraint c);
/** conflict because there is no viable value for the variable v */