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Add (updated and general) solve_for functionality for arithmetic, add congruence_explain to API to retrieve explanation for why two terms are congruent Tweak handling of smt.qi.max_instantations

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Add API solve_for(vars).
It takes a list of variables and returns a triangular solved form for the variables.
Currently for arithmetic. The solved form is a list with elements of the form (var, term, guard).
Variables solved in the tail of the list do not occur before in the list.
For example it can return a solution [(x, z, True), (y, x + z, True)] because first x was solved to be z,
then y was solved to be x + z which is the same as 2z.

Add congruent_explain that retuns an explanation for congruent terms.
Terms congruent in the final state after calling SimpleSolver().check() can be queried for
an explanation, i.e., a list of literals that collectively entail the equality under congruence closure.
The literals are asserted in the final state of search.

Adjust smt_context cancellation for the smt.qi.max_instantiations parameter.
It gets checked when qi-queue elements are consumed.
Prior it was checked on insertion time, which didn't allow for processing as many
instantations as there were in the queue. Moreover, it would not cancel the solver.
So it would keep adding instantations to the queue when it was full / depleted the
configuration limit.
This commit is contained in:
Nikolaj Bjorner 2024-12-19 23:26:42 +01:00
parent e4ab2944fe
commit 87f7a20e14
31 changed files with 428 additions and 117 deletions
Download patch file Download diff file Expand all files Collapse all files

37
src/api/api_solver.cpp
View file

@ -967,20 +967,41 @@ extern "C" {
Z3_CATCH_RETURN(nullptr);
}
Z3_ast Z3_API Z3_solver_solve_for(Z3_context c, Z3_solver s, Z3_ast a) {
Z3_ast Z3_API Z3_solver_congruence_explain(Z3_context c, Z3_solver s, Z3_ast a, Z3_ast b) {
Z3_TRY;
LOG_Z3_solver_solve_for(c, s, a);
LOG_Z3_solver_congruence_explain(c, s, a, b);
RESET_ERROR_CODE();
init_solver(c, s);
ast_manager& m = mk_c(c)->m();
expr_ref term(m);
if (!to_solver_ref(s)->solve_for(to_expr(a), term))
term = to_expr(a);
mk_c(c)->save_ast_trail(term.get());
RETURN_Z3(of_expr(term.get()));
auto exp = to_solver_ref(s)->congruence_explain(to_expr(a), to_expr(b));
mk_c(c)->save_ast_trail(exp.get());
RETURN_Z3(of_expr(exp));
Z3_CATCH_RETURN(nullptr);
}
void Z3_API Z3_solver_solve_for(Z3_context c, Z3_solver s, Z3_ast_vector vars, Z3_ast_vector terms, Z3_ast_vector guards) {
Z3_TRY;
LOG_Z3_solver_solve_for(c, s, vars, terms, guards);
RESET_ERROR_CODE();
init_solver(c, s);
ast_manager& m = mk_c(c)->m();
auto& _vars = to_ast_vector_ref(vars);
auto& _terms = to_ast_vector_ref(terms);
auto& _guards = to_ast_vector_ref(guards);
vector<solver::solution> solutions;
for (auto t : _vars)
solutions.push_back({ to_expr(t), expr_ref(m), expr_ref(m) });
to_solver_ref(s)->solve_for(solutions);
_vars.reset();
_terms.reset();
_guards.reset();
for (solver::solution const& s : solutions) {
_vars.push_back(s.var);
_terms.push_back(s.term);
_guards.push_back(s.guard);
}
Z3_CATCH;
}
class api_context_obj : public user_propagator::context_obj {
api::context* c;
public:

28
src/api/python/z3/z3.py
View file

@ -7336,26 +7336,44 @@ class Solver(Z3PPObject):
return self.cube_vs
def root(self, t):
t = _py2expr(t, self.ctx)
"""Retrieve congruence closure root of the term t relative to the current search state
The function primarily works for SimpleSolver. Terms and variables that are
eliminated during pre-processing are not visible to the congruence closure.
"""
t = _py2expr(t, self.ctx)
return _to_expr_ref(Z3_solver_congruence_root(self.ctx.ref(), self.solver, t.ast), self.ctx)
def next(self, t):
t = _py2expr(t, self.ctx)
"""Retrieve congruence closure sibling of the term t relative to the current search state
The function primarily works for SimpleSolver. Terms and variables that are
eliminated during pre-processing are not visible to the congruence closure.
"""
t = _py2expr(t, self.ctx)
return _to_expr_ref(Z3_solver_congruence_next(self.ctx.ref(), self.solver, t.ast), self.ctx)
def solve_for(self, t):
t = _py2expr(t, self.ctx)
def explain_congruent(self, a, b):
"""Explain congruence of a and b relative to the current search state"""
a = _py2expr(a, self.ctx)
b = _py2expr(b, self.ctx)
return _to_expr_ref(Z3_solver_congruence_explain(self.ctx.ref(), self.solver, a.ast, b.ast), self.ctx)
def solve_for1(self, t):
"""Retrieve a solution for t relative to linear equations maintained in the current state.
The function primarily works for SimpleSolver and when there is a solution using linear arithmetic."""
return _to_expr_ref(Z3_solver_solve_for(self.ctx.ref(), self.solver, t.ast), self.ctx)
t = _py2expr(t, self.ctx)
return _to_expr_ref(Z3_solver_solve_for1(self.ctx.ref(), self.solver, t.ast), self.ctx)
def solve_for(self, ts):
"""Retrieve a solution for t relative to linear equations maintained in the current state."""
vars = AstVector(ctx=self.ctx);
terms = AstVector(ctx=self.ctx);
guards = AstVector(ctx=self.ctx);
for t in ts:
t = _py2expr(t, self.ctx)
vars.push(t)
Z3_solver_solve_for(self.ctx.ref(), self.solver, vars.vector, terms.vector, guards.vector)
return [(vars[i], terms[i], guards[i]) for i in range(len(vars))]
def proof(self):
"""Return a proof for the last `check()`. Proof construction must be enabled."""

17
src/api/z3_api.h
View file

@ -7076,14 +7076,23 @@ extern "C" {
*/
Z3_ast Z3_API Z3_solver_congruence_next(Z3_context c, Z3_solver s, Z3_ast a);
/**
\brief retrieve explanation for congruence.
\pre root(a) = root(b)
def_API('Z3_solver_congruence_explain', AST, (_in(CONTEXT), _in(SOLVER), _in(AST), _in(AST)))
*/
Z3_ast Z3_API Z3_solver_congruence_explain(Z3_context c, Z3_solver s, Z3_ast a, Z3_ast b);
/**
\brief retrieve a 'solution' for \c t as defined by equalities in maintained by solvers.
At this point, only linear solution are supported.
\brief retrieve a 'solution' for \c variables as defined by equalities in maintained by solvers.
At this point, only linear solution are supported.
The solution to \c variables may be presented in triangular form, such that
variables used in solutions themselves have solutions.
def_API('Z3_solver_solve_for', AST, (_in(CONTEXT), _in(SOLVER), _in(AST)))
def_API('Z3_solver_solve_for', VOID, (_in(CONTEXT), _in(SOLVER), _in(AST_VECTOR), _in(AST_VECTOR), _in(AST_VECTOR)))
*/
Z3_ast Z3_API Z3_solver_solve_for(Z3_context c, Z3_solver s, Z3_ast t);
void Z3_API Z3_solver_solve_for(Z3_context c, Z3_solver s, Z3_ast_vector variables, Z3_ast_vector terms, Z3_ast_vector guards);
/**
\brief register a callback to that retrieves assumed, inferred and deleted clauses during search.

153
src/math/lp/lar_solver.cpp
View file

@ -570,8 +570,6 @@ namespace lp {
A_r().pop(k);
}
void lar_solver::set_upper_bound_witness(lpvar j, u_dependency* dep) {
m_trail.push(vector_value_trail(m_columns, j));
m_columns[j].upper_bound_witness() = dep;
@ -617,35 +615,148 @@ namespace lp {
m_touched_rows.insert(rid);
}
bool lar_solver::solve_for(unsigned j, lar_term& t, mpq& coeff) {
t.clear();
IF_VERBOSE(10, verbose_stream() << "j " << j << " is fixed " << column_is_fixed(j) << " is-base " << is_base(j) << "\n");
if (column_is_fixed(j)) {
coeff = get_value(j);
return true;
void lar_solver::check_fixed(unsigned j) {
if (column_is_fixed(j))
return;
auto explain = [&](constraint_index ci, lp::explanation const& exp) {
u_dependency* d = nullptr;
for (auto const& e : exp)
if (e.ci() != ci)
d = join_deps(d, m_dependencies.mk_leaf(e.ci()));
return d;
};
if (!column_has_lower_bound(j) || column_lower_bound(j) != get_value(j)) {
push();
mpq val = get_value(j);
auto ci = add_var_bound(j, lconstraint_kind::LT, val);
auto r = solve();
lp::explanation exp;
if (r == lp_status::INFEASIBLE)
get_infeasibility_explanation(exp);
pop();
if (r == lp_status::INFEASIBLE) {
auto d = explain(ci, exp);
update_column_type_and_bound(j, lconstraint_kind::GE, val, d);
}
solve();
}
if (!column_has_upper_bound(j) || column_upper_bound(j) != get_value(j)) {
push();
auto val = get_value(j);
auto ci = add_var_bound(j, lconstraint_kind::GT, val);
auto r = solve();
lp::explanation exp;
if (r == lp_status::INFEASIBLE)
get_infeasibility_explanation(exp);
pop();
if (r == lp_status::INFEASIBLE) {
auto d = explain(ci, exp);
update_column_type_and_bound(j, lconstraint_kind::LE, val, d);
}
solve();
}
}
void lar_solver::solve_for(unsigned_vector const& js, vector<solution>& sols) {
uint_set tabu, fixed_checked;
for (auto j : js)
solve_for(j, tabu, sols);
solve(); // clear updated columns.
auto check = [&](unsigned j) {
if (fixed_checked.contains(j))
return;
fixed_checked.insert(j);
check_fixed(j);
};
for (auto const& [j, t] : sols) {
check(j);
for (auto const& v : t)
check(v.j());
}
}
void lar_solver::solve_for(unsigned j, uint_set& tabu, vector<solution>& sols) {
if (tabu.contains(j))
return;
tabu.insert(j);
IF_VERBOSE(10, verbose_stream() << "solve for " << j << " base " << is_base(j) << " " << column_is_fixed(j) << "\n");
if (column_is_fixed(j))
return;
if (!is_base(j)) {
for (const auto & c : A_r().m_columns[j]) {
for (const auto& c : A_r().m_columns[j]) {
lpvar basic_in_row = r_basis()[c.var()];
if (tabu.contains(basic_in_row))
continue;
pivot(j, basic_in_row);
IF_VERBOSE(10, verbose_stream() << "is base " << is_base(j) << " c.var() = " << c.var() << " basic_in_row = " << basic_in_row << "\n");
break;
}
}
if (!is_base(j))
return false;
if (!is_base(j))
return;
lar_term t;
auto const& col = m_columns[j];
auto const& r = basic2row(j);
for (auto const& c : r) {
if (c.var() == j)
continue;
if (column_is_fixed(c.var()))
coeff -= get_value(c.var());
else
t.add_monomial(-c.coeff(), c.var());
if (c.var() != j)
t.add_monomial(-c.coeff(), c.var());
}
for (auto const& v : t)
solve_for(v.j(), tabu, sols);
lp::impq lo, hi;
bool lo_valid = true, hi_valid = true;
for (auto const& v : t) {
if (v.coeff().is_pos()) {
if (lo_valid && column_has_lower_bound(v.j()))
lo += column_lower_bound(v.j()) * v.coeff();
else
lo_valid = false;
if (hi_valid && column_has_upper_bound(v.j()))
hi += column_upper_bound(v.j()) * v.coeff();
else
hi_valid = false;
}
else {
if (lo_valid && column_has_upper_bound(v.j()))
lo += column_upper_bound(v.j()) * v.coeff();
else
lo_valid = false;
if (hi_valid && column_has_lower_bound(v.j()))
hi += column_lower_bound(v.j()) * v.coeff();
else
hi_valid = false;
}
}
if (lo_valid && (!column_has_lower_bound(j) || lo > column_lower_bound(j).x)) {
u_dependency* dep = nullptr;
for (auto const& v : t) {
if (v.coeff().is_pos())
dep = join_deps(dep, m_columns[v.j()].lower_bound_witness());
else
dep = join_deps(dep, m_columns[v.j()].upper_bound_witness());
}
update_column_type_and_bound(j, lo.y == 0 ? lconstraint_kind::GE : lconstraint_kind::GT, lo.x, dep);
}
IF_VERBOSE(10, verbose_stream() << "j = " << j << " t = ";
print_term(t, verbose_stream()) << " coeff = " << coeff << "\n");
return true;
if (hi_valid && (!column_has_upper_bound(j) || hi < column_upper_bound(j).x)) {
u_dependency* dep = nullptr;
for (auto const& v : t) {
if (v.coeff().is_pos())
dep = join_deps(dep, m_columns[v.j()].upper_bound_witness());
else
dep = join_deps(dep, m_columns[v.j()].lower_bound_witness());
}
update_column_type_and_bound(j, hi.y == 0 ? lconstraint_kind::LE : lconstraint_kind::LT, hi.x, dep);
}
if (!column_is_fixed(j))
sols.push_back({j, t});
}

39
src/math/lp/lar_solver.h
View file

@ -351,7 +351,15 @@ public:
* return the rest of the row as t comprising of non-fixed variables and coeff as sum of fixed variables.
* return false if j has no rows.
*/
bool solve_for(unsigned j, lar_term& t, mpq& coeff);
struct solution {
unsigned j;
lar_term t;
};
void solve_for(unsigned_vector const& js, vector<solution>& sol);
void check_fixed(unsigned j);
void solve_for(unsigned j, uint_set& tabu, vector<solution>& sol);
inline unsigned get_base_column_in_row(unsigned row_index) const {
return m_mpq_lar_core_solver.m_r_solver.get_base_column_in_row(row_index);
@ -591,21 +599,32 @@ public:
return m_columns[j].lower_bound_witness();
}
inline bool column_has_term(lpvar j) const { return m_columns[j].term() != nullptr; }
inline std::ostream& print_column_info(unsigned j, std::ostream& out) const {
m_mpq_lar_core_solver.m_r_solver.print_column_info(j, out);
if (column_has_term(j)) {
print_term_as_indices(get_term(j), out) << "\n";
} else if (column_has_term(j)) {
const lar_term& t = get_term(m_var_register.local_to_external(j));
print_term_as_indices(t, out) << "\n";
}
std::ostream& print_column_info(unsigned j, std::ostream& out) const {
m_mpq_lar_core_solver.m_r_solver.print_column_info(j, out);
if (column_has_term(j))
print_term_as_indices(get_term(j), out) << "\n";
display_column_explanation(out, j);
return out;
}
std::ostream& display_column_explanation(std::ostream& out, unsigned j) const {
const column& ul = m_columns[j];
svector<unsigned> vs1, vs2;
m_dependencies.linearize(ul.lower_bound_witness(), vs1);
m_dependencies.linearize(ul.upper_bound_witness(), vs2);
if (!vs1.empty())
out << "lo: " << vs1;
if (!vs2.empty())
out << "hi: " << vs2;
if (!vs1.empty() || !vs2.empty())
out << "\n";
return out;
}
void subst_known_terms(lar_term*);
inline std::ostream& print_column_bound_info(unsigned j, std::ostream& out) const {
std::ostream& print_column_bound_info(unsigned j, std::ostream& out) const {
return m_mpq_lar_core_solver.m_r_solver.print_column_bound_info(j, out);
}

1
src/muz/spacer/spacer_iuc_solver.h
View file

@ -124,6 +124,7 @@ public:
expr_ref_vector cube(expr_ref_vector&, unsigned) override { return expr_ref_vector(m); }
expr* congruence_root(expr* e) override { return e; }
expr* congruence_next(expr* e) override { return e; }
expr_ref congruence_explain(expr *a, expr *b) override { return expr_ref(m.mk_eq(a, b), m); }
void get_levels(ptr_vector<expr> const& vars, unsigned_vector& depth) override { m_solver.get_levels(vars, depth); }
expr_ref_vector get_trail(unsigned max_level) override { return m_solver.get_trail(max_level); }

1
src/opt/opt_solver.h
View file

@ -111,6 +111,7 @@ namespace opt {
expr_ref_vector cube(expr_ref_vector&, unsigned) override { return expr_ref_vector(m); }
expr* congruence_root(expr* e) override { return e; }
expr* congruence_next(expr* e) override { return e; }
expr_ref congruence_explain(expr* a, expr* b) override { return expr_ref(m.mk_eq(a, b), m); }
void set_phase(expr* e) override { m_context.set_phase(e); }
phase* get_phase() override { return m_context.get_phase(); }
void set_phase(phase* p) override { m_context.set_phase(p); }

1
src/sat/sat_solver/inc_sat_solver.cpp
View file

@ -480,6 +480,7 @@ public:
expr* congruence_next(expr* e) override { return e; }
expr* congruence_root(expr* e) override { return e; }
expr_ref congruence_explain(expr* a, expr* b) override { return expr_ref(m.mk_eq(a, b), m); }
lbool get_consequences_core(expr_ref_vector const& assumptions, expr_ref_vector const& vars, expr_ref_vector& conseq) override {

1
src/sat/sat_solver/sat_smt_solver.cpp
View file

@ -426,6 +426,7 @@ public:
expr* congruence_next(expr* e) override { return e; }
expr* congruence_root(expr* e) override { return e; }
expr_ref congruence_explain(expr* a, expr* b) override { return expr_ref(m.mk_eq(a, b), m); }
lbool find_mutexes(expr_ref_vector const& vars, vector<expr_ref_vector>& mutexes) override {

5
src/smt/qi_queue.cpp
View file

@ -153,6 +153,11 @@ namespace smt {
if (m_context.get_cancel_flag()) {
break;
}
if (m_stats.m_num_instances > m_params.m_qi_max_instances) {
m_context.set_reason_unknown("maximum number of quantifier instances was reached");
m_context.set_internal_completed();
break;
}
fingerprint * f = curr.m_qb;
quantifier * qa = static_cast<quantifier*>(f->get_data());

2
src/smt/qi_queue.h
View file

@ -51,7 +51,7 @@ namespace smt {
cost_evaluator m_evaluator;
cached_var_subst m_subst;
svector<float> m_vals;
double m_eager_cost_threshold;
double m_eager_cost_threshold = 0;
struct entry {
fingerprint * m_qb;
float m_cost;

23
src/smt/smt_context.cpp
View file

@ -104,7 +104,7 @@ namespace smt {
*/
bool context::get_cancel_flag() {
if (l_true == m_sls_completed && !m.limit().suspended()) {
if (l_true == m_internal_completed && !m.limit().suspended()) {
m_last_search_failure = CANCELED;
return true;
}
@ -3509,11 +3509,11 @@ namespace smt {
display_profile(verbose_stream());
if (r == l_true && get_cancel_flag())
r = l_undef;
if (r == l_undef && m_sls_completed == l_true && has_sls_model()) {
if (r == l_undef && m_internal_completed == l_true && has_sls_model()) {
m_last_search_failure = OK;
r = l_true;
}
m_sls_completed = l_false;
m_internal_completed = l_false;
if (r == l_true && gparams::get_value("model_validate") == "true") {
recfun::util u(m);
if (u.get_rec_funs().empty() && m_proto_model) {
@ -3753,7 +3753,7 @@ namespace smt {
m_phase_default = false;
m_case_split_queue ->init_search_eh();
m_next_progress_sample = 0;
m_sls_completed = l_undef;
m_internal_completed = l_undef;
if (m.has_type_vars() && !m_theories.get_plugin(poly_family_id))
register_plugin(alloc(theory_polymorphism, *this));
TRACE("literal_occ", display_literal_num_occs(tout););
@ -4653,16 +4653,13 @@ namespace smt {
if (th == nullptr)
return false;
return th->get_value(n, value);
}
void context::solve_for(vector<solution>& sol) {
for (auto th : m_theories)
if (th)
th->solve_for(sol);
}
bool context::solve_for(enode * n, expr_ref & term) {
sort * s = n->get_sort();
family_id fid = s->get_family_id();
theory * th = get_theory(fid);
if (th == nullptr)
return false;
return th->solve_for(n, term);
}
bool context::update_model(bool refinalize) {
final_check_status fcs = FC_DONE;

12
src/smt/smt_context.h
View file

@ -130,7 +130,7 @@ namespace smt {
class parallel* m_par = nullptr;
unsigned m_par_index = 0;
bool m_internalizing_assertions = false;
lbool m_sls_completed = l_undef;
lbool m_internal_completed = l_undef;
// -----------------------------------
@ -291,9 +291,9 @@ namespace smt {
bool get_cancel_flag();
void set_sls_completed() {
if (m_sls_completed == l_undef)
m_sls_completed = l_true;
void set_internal_completed() {
if (m_internal_completed == l_undef)
m_internal_completed = l_true;
}
region & get_region() {
@ -1377,13 +1377,13 @@ namespace smt {
// -----------------------------------
//
// Model checking... (must be improved)
// Value extraction and solving
//
// -----------------------------------
public:
bool get_value(enode * n, expr_ref & value);
bool solve_for(enode* n, expr_ref& term);
void solve_for(vector<solution>& sol);
// -----------------------------------
//

29
src/smt/smt_kernel.cpp
View file

@ -20,6 +20,7 @@ Revision History:
#include "smt/smt_context.h"
#include "smt/smt_lookahead.h"
#include "ast/ast_smt2_pp.h"
#include "ast/ast_util.h"
#include "smt/params/smt_params_helper.hpp"
namespace smt {
@ -213,11 +214,14 @@ namespace smt {
return out;
}
bool kernel::solve_for(expr* e, expr_ref& term) {
smt::enode* n = m_imp->m_kernel.find_enode(e);
if (!n)
return false;
return m_imp->m_kernel.solve_for(n, term);
void kernel::solve_for(vector<solver::solution>& sol) {
vector<smt::solution> solution;
for (auto const& [v, t, g] : sol)
solution.push_back({ v, t, g });
m_imp->m_kernel.solve_for(solution);
sol.reset();
for (auto s : solution)
sol.push_back({ s.var, s.term, s.guard });
}
expr* kernel::congruence_root(expr * e) {
@ -234,6 +238,21 @@ namespace smt {
return n->get_next()->get_expr();
}
expr_ref kernel::congruence_explain(expr* a, expr* b) {
auto& ctx = m_imp->m_kernel;
ast_manager& m = ctx.get_manager();
smt::enode* n1 = ctx.find_enode(a);
smt::enode* n2 = ctx.find_enode(b);
if (!n1 || !n2 || n1->get_root() != n2->get_root())
return expr_ref(m.mk_eq(a, b), m);
literal_vector lits;
ctx.get_cr().eq2literals(n1, n2, lits);
expr_ref_vector es(m);
for (auto lit : lits)
es.push_back(ctx.literal2expr(lit));
return mk_and(es);
}
void kernel::collect_statistics(::statistics & st) const {
m_imp->m_kernel.collect_statistics(st);
}

4
src/smt/smt_kernel.h
View file

@ -246,7 +246,9 @@ namespace smt {
expr* congruence_root(expr* e);
bool solve_for(expr* e, expr_ref& term);
expr_ref congruence_explain(expr* a, expr* b);
void solve_for(vector<solver::solution>& s);
/**
\brief retrieve depth of variables from decision stack.

7
src/smt/smt_quantifier.cpp
View file

@ -133,7 +133,7 @@ namespace smt {
q::quantifier_stat_gen m_qstat_gen;
ptr_vector<quantifier> m_quantifiers;
scoped_ptr<quantifier_manager_plugin> m_plugin;
unsigned m_num_instances;
unsigned m_num_instances = 0;
imp(quantifier_manager & wrapper, context & ctx, smt_params & p, quantifier_manager_plugin * plugin):
m_wrapper(wrapper),
@ -142,7 +142,6 @@ namespace smt {
m_qi_queue(m_wrapper, ctx, p),
m_qstat_gen(ctx.get_manager(), ctx.get_region()),
m_plugin(plugin) {
m_num_instances = 0;
m_qi_queue.setup();
}
@ -297,9 +296,7 @@ namespace smt {
vector<std::tuple<enode *, enode *>> & used_enodes) {
max_generation = std::max(max_generation, get_generation(q));
if (m_num_instances > m_params.m_qi_max_instances) {
return false;
}
get_stat(q)->update_max_generation(max_generation);
fingerprint * f = m_context.add_fingerprint(q, q->get_id(), num_bindings, bindings, def);
if (f) {

3
src/smt/smt_solver.cpp
View file

@ -337,7 +337,8 @@ namespace {
expr* congruence_next(expr* e) override { return m_context.congruence_next(e); }
expr* congruence_root(expr* e) override { return m_context.congruence_root(e); }
bool solve_for(expr* e, expr_ref& term) override { return m_context.solve_for(e, term); }
expr_ref congruence_explain(expr* a, expr* b) override { return m_context.congruence_explain(a, b); }
void solve_for(vector<solver::solution>& s) override { m_context.solve_for(s); }
expr_ref_vector cube(expr_ref_vector& vars, unsigned cutoff) override {

8
src/smt/smt_theory.h
View file

@ -29,6 +29,12 @@ namespace smt {
class model_generator;
class model_value_proc;
struct solution {
expr* var;
expr_ref term;
expr_ref guard;
};
class theory {
protected:
theory_id m_id;
@ -605,7 +611,7 @@ namespace smt {
virtual char const * get_name() const { return "unknown"; }
virtual bool solve_for(enode* n, expr_ref& r) { return false; }
virtual void solve_for(vector<solution>& s) {}
// -----------------------------------
//

145
src/smt/theory_lra.cpp
View file

@ -3169,7 +3169,7 @@ public:
typedef std::pair<lp::constraint_index, rational> constraint_bound;
vector<constraint_bound> m_lower_terms;
vector<constraint_bound> m_upper_terms;
void propagate_eqs(lp::lpvar t, lp::constraint_index ci1, lp::lconstraint_kind k, api_bound& b, rational const& value) {
u_dependency* ci2 = nullptr;
auto pair = [&]() { return lp().dep_manager().mk_join(lp().dep_manager().mk_leaf(ci1), ci2); };
@ -3392,9 +3392,8 @@ public:
}
void set_evidence(lp::constraint_index idx, literal_vector& core, svector<enode_pair>& eqs) {
if (idx == UINT_MAX) {
return;
}
if (idx == UINT_MAX)
return;
switch (m_constraint_sources[idx]) {
case inequality_source: {
literal lit = m_inequalities[idx];
@ -3629,33 +3628,116 @@ public:
return lp().has_upper_bound(vi, dep, val, is_strict);
}
bool solve_for(enode* n, expr_ref& term) {
theory_var v = n->get_th_var(get_id());
if (!is_registered_var(v))
return false;
lpvar vi = get_lpvar(v);
lp::lar_term t;
rational coeff;
if (!lp().solve_for(vi, t, coeff))
return false;
rational lc(1);
if (is_int(v)) {
lc = denominator(coeff);
for (auto const& cv : t)
lc = lcm(denominator(cv.coeff()), lc);
if (lc != 1) {
coeff *= lc;
t *= lc;
}
}
term = mk_term(t, is_int(v));
if (coeff != 0)
term = a.mk_add(a.mk_numeral(coeff, is_int(v)), term);
if (lc != 1)
term = a.mk_idiv(term, a.mk_numeral(lc, true));
return true;
void solve_fixed(enode* n, lpvar j, expr_ref& term, expr_ref& guard) {
term = a.mk_numeral(lp().get_value(j), a.is_int(n->get_expr()));
reset_evidence();
add_explain(j);
guard = extract_explain();
}
void add_explain(unsigned j) {
auto d = lp().get_bound_constraint_witnesses_for_column(j);
set_evidence(d, m_core, m_eqs);
}
expr_ref extract_explain() {
expr_ref_vector es(m);
for (auto [l, r] : m_eqs)
es.push_back(a.mk_eq(l->get_expr(), r->get_expr()));
for (auto l : m_core)
es.push_back(ctx().literal2expr(l));
// remove duplicats from es:
std::stable_sort(es.data(), es.data() + es.size());
unsigned j = 0;
for (unsigned i = 0; i < es.size(); ++i) {
if (i > 0 && es.get(i) == es.get(i - 1))
continue;
es[j++] = es.get(i);
}
es.shrink(j);
return mk_and(es);
}
void solve_term(enode* n, lp::lar_term & lt, expr_ref& term, expr_ref& guard) {
bool is_int = a.is_int(n->get_expr());
bool all_int = is_int;
lp::lar_term t;
rational coeff(0);
expr_ref_vector guards(m);
reset_evidence();
for (auto const& cv : lt) {
if (lp().column_is_fixed(cv.j())) {
coeff += lp().get_value(cv.j()) * cv.coeff();
add_explain(cv.j());
}
else
t.add_monomial(cv.coeff(), cv.j());
}
guards.push_back(extract_explain());
rational lc = denominator(coeff);
for (auto const& cv : t) {
lc = lcm(denominator(cv.coeff()), lc);
all_int &= lp().column_is_int(cv.j());
}
if (lc != 1)
t *= lc, coeff *= lc;
term = mk_term(t, is_int);
if (coeff != 0)
term = a.mk_add(term, a.mk_numeral(coeff, is_int));
if (lc == 1) {
guard = mk_and(guards);
return;
}
expr_ref lce(a.mk_numeral(lc, true), m);
if (all_int)
guards.push_back(m.mk_eq(a.mk_mod(term, lce), a.mk_int(0)));
else if (is_int)
guards.push_back(a.mk_is_int(a.mk_div(term, lce)));
term = a.mk_idiv(term, lce);
guard = mk_and(guards);
}
void solve_for(vector<solution>& solutions) {
unsigned_vector vars;
unsigned j = 0;
for (auto [e, t, g] : solutions) {
auto n = get_enode(e);
if (!n) {
solutions[j++] = { e, t, g };
continue;
}
theory_var v = n->get_th_var(get_id());
if (!is_registered_var(v))
solutions[j++] = { e, t, g };
else
vars.push_back(get_lpvar(v));
}
solutions.shrink(j);
expr_ref term(m), guard(m);
vector<lp::lar_solver::solution> sols;
lp().solve_for(vars, sols);
uint_set seen;
for (auto& s : sols) {
auto n = get_enode(lp().local_to_external(s.j));
if (lp().column_is_fixed(s.j))
solve_fixed(n, s.j, term, guard);
else
solve_term(n, s.t, term, guard);
solutions.push_back({ n->get_expr(), term, guard});
seen.insert(s.j);
}
for (auto j : vars) {
if (seen.contains(j) || !lp().column_is_fixed(j))
continue;
auto n = get_enode(lp().local_to_external(j));
solve_fixed(n, j, term, guard);
solutions.push_back({ n->get_expr(), term, guard });
}
}
bool get_upper(enode* n, expr_ref& r) {
bool is_strict;
rational val;
@ -4166,8 +4248,9 @@ bool theory_lra::get_lower(enode* n, rational& r, bool& is_strict) {
bool theory_lra::get_upper(enode* n, rational& r, bool& is_strict) {
return m_imp->get_upper(n, r, is_strict);
}
bool theory_lra::solve_for(enode* n, expr_ref& r) {
return m_imp->solve_for(n, r);
void theory_lra::solve_for(vector<solution>& sol) {
m_imp->solve_for(sol);
}
void theory_lra::display(std::ostream & out) const {

2
src/smt/theory_lra.h
View file

@ -93,7 +93,7 @@ namespace smt {
bool get_upper(enode* n, expr_ref& r);
bool get_lower(enode* n, rational& r, bool& is_strict);
bool get_upper(enode* n, rational& r, bool& is_strict);
bool solve_for(enode* n, expr_ref& r) override;
void solve_for(vector<solution>& s) override;
void display(std::ostream & out) const override;

2
src/smt/theory_sls.cpp
View file

@ -58,7 +58,7 @@ namespace smt {
}
void theory_sls::set_finished() {
ctx.set_sls_completed();
ctx.set_internal_completed();
}
bool theory_sls::get_smt_value(expr* v, expr_ref& value) {

1
src/solver/combined_solver.cpp
View file

@ -277,6 +277,7 @@ public:
expr* congruence_next(expr* e) override { switch_inc_mode(); return m_solver2->congruence_next(e); }
expr* congruence_root(expr* e) override { switch_inc_mode(); return m_solver2->congruence_root(e); }
expr_ref congruence_explain(expr* a, expr* b) override { switch_inc_mode(); return m_solver2->congruence_explain(a, b); }
expr * get_assumption(unsigned idx) const override {

1
src/solver/simplifier_solver.cpp
View file

@ -365,6 +365,7 @@ public:
expr* congruence_root(expr* e) override { return s->congruence_root(e); }
expr* congruence_next(expr* e) override { return s->congruence_next(e); }
expr_ref congruence_explain(expr* a, expr* b) override { return s->congruence_explain(a, b); }
std::ostream& display(std::ostream& out, unsigned n, expr* const* assumptions) const override {
return s->display(out, n, assumptions);
}

1
src/solver/slice_solver.cpp
View file

@ -393,6 +393,7 @@ public:
expr* congruence_root(expr* e) override { return s->congruence_root(e); }
expr* congruence_next(expr* e) override { return s->congruence_next(e); }
expr_ref congruence_explain(expr* a, expr* b) override { return s->congruence_explain(a, b); }
std::ostream& display(std::ostream& out, unsigned n, expr* const* assumptions) const override {
return s->display(out, n, assumptions);
}

13
src/solver/solver.h
View file

@ -27,6 +27,7 @@ class solver;
class model_converter;
class solver_factory {
public:
virtual ~solver_factory() = default;
@ -249,9 +250,17 @@ public:
virtual expr* congruence_next(expr* e) = 0;
/**
\brief try to solve for term e (when e is arithmetical).
\brief expose explanation for congruence.
*/
virtual bool solve_for(expr* e, expr_ref& term) { return false; }
virtual expr_ref congruence_explain(expr* a, expr* b) = 0;
struct solution {
expr* var;
expr_ref term;
expr_ref guard;
};
virtual void solve_for(vector<solution>& s) {}
/**
\brief Display the content of this solver.

3
src/solver/solver_pool.cpp
View file

@ -81,7 +81,7 @@ public:
}
void push_params() override {m_base->push_params();}
void pop_params() override {m_base->pop_params();}
void collect_param_descrs(param_descrs & r) override { m_base->collect_param_descrs(r); }
void collect_statistics(statistics & st) const override { m_base->collect_statistics(st); }
unsigned get_num_assertions() const override { return m_base->get_num_assertions(); }
@ -264,6 +264,7 @@ public:
expr* congruence_next(expr* e) override { return e; }
expr* congruence_root(expr* e) override { return e; }
expr_ref congruence_explain(expr* a, expr* b) override { return expr_ref(m.mk_eq(a, b), m); }
ast_manager& get_manager() const override { return m_base->get_manager(); }

1
src/solver/tactic2solver.cpp
View file

@ -145,6 +145,7 @@ public:
expr* congruence_next(expr* e) override { return e; }
expr* congruence_root(expr* e) override { return e; }
expr_ref congruence_explain(expr* a, expr* b) override { return expr_ref(get_manager().mk_eq(a, b), get_manager()); }
model_converter_ref get_model_converter() const override { return m_mc; }

1
src/tactic/fd_solver/bounded_int2bv_solver.cpp
View file

@ -212,6 +212,7 @@ public:
ast_manager& get_manager() const override { return m; }
expr* congruence_next(expr* e) override { return m_solver->congruence_next(e); }
expr* congruence_root(expr* e) override { return m_solver->congruence_root(e); }
expr_ref congruence_explain(expr* a, expr* b) override { return m_solver->congruence_explain(a, b); }
expr_ref_vector cube(expr_ref_vector& vars, unsigned backtrack_level) override { flush_assertions(); return m_solver->cube(vars, backtrack_level); }
lbool find_mutexes(expr_ref_vector const& vars, vector<expr_ref_vector>& mutexes) override { return m_solver->find_mutexes(vars, mutexes); }
lbool get_consequences_core(expr_ref_vector const& asms, expr_ref_vector const& vars, expr_ref_vector& consequences) override {

1
src/tactic/fd_solver/enum2bv_solver.cpp
View file

@ -133,6 +133,7 @@ public:
}
expr* congruence_next(expr* e) override { return m_solver->congruence_next(e); }
expr* congruence_root(expr* e) override { return m_solver->congruence_root(e); }
expr_ref congruence_explain(expr* a, expr* b) override { return m_solver->congruence_explain(a, b); }
lbool get_consequences_core(expr_ref_vector const& asms, expr_ref_vector const& vars, expr_ref_vector& consequences) override {

1
src/tactic/fd_solver/pb2bv_solver.cpp
View file

@ -124,6 +124,7 @@ public:
expr_ref_vector cube(expr_ref_vector& vars, unsigned backtrack_level) override { flush_assertions(); return m_solver->cube(vars, backtrack_level); }
expr* congruence_next(expr* e) override { return m_solver->congruence_next(e); }
expr* congruence_root(expr* e) override { return m_solver->congruence_root(e); }
expr_ref congruence_explain(expr* a, expr* b) override { return m_solver->congruence_explain(a, b); }
lbool find_mutexes(expr_ref_vector const& vars, vector<expr_ref_vector>& mutexes) override { return m_solver->find_mutexes(vars, mutexes); }
lbool get_consequences_core(expr_ref_vector const& asms, expr_ref_vector const& vars, expr_ref_vector& consequences) override {
flush_assertions();

2
src/tactic/fd_solver/smtfd_solver.cpp
View file

@ -2070,6 +2070,8 @@ namespace smtfd {
expr* congruence_root(expr* e) override { return e; }
expr* congruence_next(expr* e) override { return e; }
expr_ref congruence_explain(expr* a, expr* b) override { return expr_ref(m.mk_eq(a, b), m); }
lbool get_consequences_core(expr_ref_vector const& asms, expr_ref_vector const& vars, expr_ref_vector& consequences) override {
return l_undef;