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Polysat: constraint refactor cont'd, deduplicate constraints (#5520)

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* Assign boolean variables only to long-lived constraints, and deduplicate constraints when they are created

* scoped_signed_constraint

* update other classes

* fix

* Don't use scoped_ptr<constraint> with dedup()
This commit is contained in:
Jakob Rath 2021-08-30 19:00:27 +02:00 • committed by GitHub
parent ebaea2159e
commit 0c1e44da77
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16 changed files with 365 additions and 298 deletions
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28
src/math/polysat/conflict_core.h
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@ -18,8 +18,14 @@ namespace polysat {
/** Conflict state, represented as core (~negation of clause). */
class conflict_core {
// TODO: core needs to own the constraint literals...
vector<constraint_literal> m_constraints;
vector<signed_constraint> m_constraints;
/** Storage for new constraints that may not yet have a boolean variable yet */
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;
/** 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;
@ -28,8 +34,11 @@ 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<constraint_literal> const& constraints() const { return m_constraints; }
vector<signed_constraint> const& constraints() const { return m_constraints; }
bool needs_model() const { return m_needs_model; }
bool empty() const {
@ -39,15 +48,24 @@ namespace polysat {
void reset() {
m_constraints.reset();
m_needs_model = false;
gc();
SASSERT(empty());
}
/** for bailing out with a conflict at the base level */
void set(std::nullptr_t);
/** conflict because the constraint c is false under current variable assignment */
void set(constraint_literal c);
void set(signed_constraint c);
/** conflict because there is no viable value for the variable v */
void set(pvar v, vector<constraint_literal> const& cjust_v);
void set(pvar v, vector<signed_constraint> const& cjust_v);
/** Garbage-collect temporary constraints */
void gc() {
for (auto* c : m_storage)
if (!c->has_bvar())
dealloc(c);
m_storage.reset();
}
std::ostream& display(std::ostream& out) const;
};