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

Polysat: conflict resolution wip (#5529)

Browse source 
* conflict_core doesn't need gc() anymore

* update comments, ensure_bvar for new constraints

* Make sure constraints can only be created through constraint_manager

* fix constraint::display if no boolean variable is assigned

* Move clause into separate file

* Add conflict_core binary resolution

* conflict_core additions

* reactivate conflict resolution outer loop

* wip

* seems commented includes break CI build
This commit is contained in:
Jakob Rath 2021-09-01 18:10:10 +02:00 • committed by GitHub
parent 8b374c3745
commit dc547510db
No known key found for this signature in database
GPG key ID: 4AEE18F83AFDEB23
16 changed files with 423 additions and 335 deletions
Download patch file Download diff file Expand all files Collapse all files

36
src/math/polysat/conflict_core.h
View file

@ -16,14 +16,12 @@ Author:
namespace polysat {
class solver;
/** Conflict state, represented as core (~negation of clause). */
class conflict_core {
vector<signed_constraint> m_constraints;
/** Storage for new constraints that may not yet have a boolean variable yet */
// TODO: not necessary anymore, if we keep constraint_manager::gc()
ptr_vector<constraint> m_storage;
// 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;
@ -35,21 +33,20 @@ namespace polysat {
// 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.
public:
~conflict_core() {
gc();
}
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_constraints.size() == 1 && !m_constraints[0]; }
bool empty() const {
return m_constraints.empty() && !m_needs_model;
return m_constraints.empty() && !m_needs_model && m_conflict_var == null_var;
}
void reset() {
m_constraints.reset();
m_needs_model = false;
gc();
m_conflict_var = null_var;
SASSERT(empty());
}
@ -58,20 +55,21 @@ namespace polysat {
/** 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 */
void set(pvar v, vector<signed_constraint> const& cjust_v);
void set(pvar v);
/** Garbage-collect temporary constraints */
void gc() {
for (auto* c : m_storage)
if (!c->has_bvar())
dealloc(c);
m_storage.reset();
}
void push(signed_constraint c);
/** Perform boolean resolution with the clause upon variable 'var'.
* Precondition: core/clause contain complementary 'var'-literals.
*/
void resolve(sat::bool_var var, clause const& cl);
void resolve(constraint_manager const& m, sat::bool_var var, clause const& cl);
/** Convert the core into a lemma to be learned. */
clause_ref build_lemma(solver& s, unsigned trail_idx);
using const_iterator = decltype(m_constraints)::const_iterator;
const_iterator begin() { return constraints().begin(); }
const_iterator end() { return constraints().end(); }
std::ostream& display(std::ostream& out) const;
};