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Separate constraint creation from activation; add sign/polarity to constraints (#5217)

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* Separate constraint creation from activation

* Basic recursive handling of disjunctive lemmas for unit tests

* Set learned constraint to true immediately

* Preliminary support for negated constraints
This commit is contained in:
Jakob Rath 2021-04-26 18:55:58 +02:00 • committed by GitHub
parent 2fac9e6e66
commit 9e505d60f0
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GPG key ID: 4AEE18F83AFDEB23
12 changed files with 244 additions and 73 deletions
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38
src/math/polysat/solver.h
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@ -65,6 +65,13 @@ namespace polysat {
scoped_ptr_vector<constraint> m_constraints;
scoped_ptr_vector<constraint> m_redundant;
// Map boolean variables to constraints
bool_var m_next_bvar = 2; // TODO: later, bool vars come from external supply
ptr_vector<constraint> m_bv2constraint;
void insert_bv2c(bool_var bv, constraint* c) { m_bv2constraint.setx(bv, c, nullptr); }
void erase_bv2c(bool_var bv) { m_bv2constraint[bv] = nullptr; }
constraint* get_bv2c(bool_var bv) const { return m_bv2constraint.get(bv, nullptr); }
// Per variable information
vector<bdd> m_viable; // set of viable values.
vector<rational> m_value; // assigned value
@ -204,7 +211,7 @@ namespace polysat {
void backjump(unsigned new_level);
void add_lemma(constraint* c);
void add_constraint(constraint* c);
void new_constraint(constraint* c);
bool invariant();
bool invariant(scoped_ptr_vector<constraint> const& cs);
@ -222,9 +229,20 @@ namespace polysat {
/**
* End-game satisfiability checker.
*
* Returns l_undef if the search cannot proceed.
* Possible reasons:
* - Resource limits are exhausted.
* - A disjunctive lemma should be learned. The disjunction needs to be handled externally.
*/
lbool check_sat();
/**
* Returns the disjunctive lemma that should be learned,
* or an empty vector if check_sat() terminated for a different reason.
*/
bool_var_vector get_lemma() { NOT_IMPLEMENTED_YET(); return {}; };
/**
* retrieve unsat core dependencies
*/
@ -241,10 +259,17 @@ namespace polysat {
pdd var(pvar v) { return m_vars[v]; }
/**
* Add polynomial constraints
* Create polynomial constraints (but do not activate them).
* Each constraint is tracked by a dependency.
* assign sets the 'index'th bit of var.
*/
bool_var new_eq(pdd const& p, unsigned dep = null_dependency);
bool_var new_diseq(pdd const& p, unsigned dep = null_dependency);
bool_var new_ule(pdd const& p, pdd const& q, unsigned dep = null_dependency, csign_t sign = pos_t);
bool_var new_ult(pdd const& p, pdd const& q, unsigned dep = null_dependency);
bool_var new_sle(pdd const& p, pdd const& q, unsigned dep = null_dependency, csign_t sign = pos_t);
bool_var new_slt(pdd const& p, pdd const& q, unsigned dep = null_dependency);
/** Create and activate polynomial constraints. */
void add_eq(pdd const& p, unsigned dep = null_dependency);
void add_diseq(pdd const& p, unsigned dep = null_dependency);
void add_ule(pdd const& p, pdd const& q, unsigned dep = null_dependency);
@ -252,6 +277,11 @@ namespace polysat {
void add_sle(pdd const& p, pdd const& q, unsigned dep = null_dependency);
void add_slt(pdd const& p, pdd const& q, unsigned dep = null_dependency);
/**
* Activate the constraint corresponding to the given boolean variable.
* Note: to deactivate, use push/pop.
*/
void assign_eh(bool_var v, bool is_true);
/**
* main state transitions.
@ -264,7 +294,7 @@ namespace polysat {
* Adds so-called user-scope.
*/
void push();
void pop(unsigned num_scopes);
void pop(unsigned num_scopes = 1);
std::ostream& display(std::ostream& out) const;