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extend dcert to disunification constraints that arithmetic theory needs to satisfy

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2020-01-25 22:38:13 -06:00
parent 5497022f5c
commit eb3fc4f47e
4 changed files with 78 additions and 15 deletions
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49
src/qe/qe_mbi.cpp
View file

@ -46,7 +46,6 @@ Notes:
namespace qe {
void mbi_plugin::set_shared(expr* a, expr* b) {
TRACE("qe", tout << mk_pp(a, m) << " " << mk_pp(b, m) << "\n";);
struct fun_proc {
obj_hashtable<func_decl> s;
void operator()(app* a) { if (is_uninterp(a)) s.insert(a->get_decl()); }
@ -75,6 +74,9 @@ namespace qe {
};
intersect_proc symbols_in_b(*this, symbols_in_a.s);
quick_for_each_expr(symbols_in_b, marks, b);
TRACE("qe",
tout << mk_pp(a, m) << "\n" << mk_pp(b, m) << "\n";
for (func_decl* f : m_shared) tout << f->get_name() << " "; tout << "\n";);
}
lbool mbi_plugin::check(expr_ref_vector& lits, model_ref& mdl) {
@ -349,17 +351,58 @@ namespace qe {
/**
\brief add difference certificates to formula.
\brief add difference certificates to formula.
*/
void uflia_mbi::add_dcert(model_ref& mdl, expr_ref_vector& lits) {
term_graph tg(m);
add_arith_dcert(*mdl.get(), lits);
func_decl_ref_vector shared(m_shared_trail);
tg.set_vars(shared, false);
lits.append(tg.dcert(*mdl.get(), lits));
TRACE("qe", tout << "project: " << lits << "\n";);
}
/**
Add disequalities between functions that appear in arithmetic context.
*/
void uflia_mbi::add_arith_dcert(model& mdl, expr_ref_vector& lits) {
obj_map<func_decl, ptr_vector<app>> apps;
arith_util a(m);
for (expr* e : subterms(lits)) {
if (a.is_int_real(e) && is_uninterp(e) && to_app(e)->get_num_args() > 0) {
func_decl* f = to_app(e)->get_decl();
auto* v = apps.insert_if_not_there2(f, ptr_vector<app>());
v->get_data().m_value.push_back(to_app(e));
}
}
for (auto const& kv : apps) {
ptr_vector<app> const& es = kv.m_value;
expr_ref_vector values(m);
for (expr* e : kv.m_value) values.push_back(mdl(e));
for (unsigned i = 0; i < es.size(); ++i) {
expr* v1 = values.get(i);
for (unsigned j = i + 1; j < es.size(); ++j) {
expr* v2 = values.get(j);
if (v1 != v2) {
add_arith_dcert(mdl, lits, es[i], es[j]);
}
}
}
}
}
void uflia_mbi::add_arith_dcert(model& mdl, expr_ref_vector& lits, app* a, app* b) {
arith_util arith(m);
SASSERT(a->get_decl() == b->get_decl());
for (unsigned i = a->get_num_args(); i-- > 0; ) {
expr* arg1 = a->get_arg(i), *arg2 = b->get_arg(i);
if (arith.is_int_real(arg1) && mdl(arg1) != mdl(arg2)) {
lits.push_back(m.mk_not(m.mk_eq(arg1, arg2)));
return;
}
}
}
/**
* \brief project private symbols.
*/

2
src/qe/qe_mbi.h
View file

@ -123,6 +123,8 @@ namespace qe {
void order_avars(app_ref_vector& avars);
void add_dcert(model_ref& mdl, expr_ref_vector& lits);
void add_arith_dcert(model& mdl, expr_ref_vector& lits);
void add_arith_dcert(model& mdl, expr_ref_vector& lits, app* a, app* b);
app_ref_vector get_arith_vars(expr_ref_vector const& lits);
vector<def> arith_project(model_ref& mdl, app_ref_vector& avars, expr_ref_vector& lits);
void project_euf(model_ref& mdl, expr_ref_vector& lits);

12
src/qe/qe_solve_plugin.cpp
View file

@ -100,7 +100,7 @@ namespace qe {
v = e;
a_val = rational(1)/a_val;
t = mk_term(is_int, a_val, sign, done);
TRACE("qe", tout << mk_pp(lhs, m) << " " << mk_pp(rhs, m) << " " << mk_pp(e, m) << " := " << t << "\n";);
TRACE("qe", tout << mk_pp(e, m) << " := " << t << "\n";);
return true;
}
else {
@ -147,7 +147,7 @@ namespace qe {
}
expr_ref mk_eq_core (expr *e1, expr *e2) {
expr_ref mk_eq_core(expr *e1, expr *e2) {
expr_ref v(m), t(m);
if (solve(e1, e2, v, t)) {
return expr_ref(m.mk_eq(v, t), m);
@ -201,7 +201,7 @@ namespace qe {
return a.mk_ge(arg, mk_zero());
}
bool mk_le_core (expr *arg1, expr * arg2, expr_ref &result) {
bool mk_le_core(expr *arg1, expr * arg2, expr_ref &result) {
// t <= -1 ==> t < 0 ==> ! (t >= 0)
rational n;
if (a.is_int (arg1) && a.is_minus_one (arg2)) {
@ -220,16 +220,16 @@ namespace qe {
return false;
}
expr * mk_zero () {
expr * mk_zero() {
return a.mk_numeral (rational (0), true);
}
bool is_one (expr const * n) const {
bool is_one(expr const * n) const {
rational val;
return a.is_numeral (n, val) && val.is_one ();
}
bool mk_ge_core (expr * arg1, expr * arg2, expr_ref &result) {
bool mk_ge_core(expr * arg1, expr * arg2, expr_ref &result) {
// t >= 1 ==> t > 0 ==> ! (t <= 0)
rational n;
if (a.is_int (arg1) && is_one (arg2)) {

30
src/qe/qe_term_graph.cpp
View file

@ -725,9 +725,22 @@ namespace qe {
TRACE("qe", tout << "skipping " << mk_pp(lit, m) << "\n";);
}
}
remove_duplicates(res);
TRACE("qe", tout << "literals: " << res << "\n";);
}
void remove_duplicates(expr_ref_vector& v) {
obj_hashtable<expr> seen;
unsigned j = 0;
for (expr* e : v) {
if (!seen.contains(e)) {
v[j++] = e;
seen.insert(e);
}
}
v.shrink(j);
}
vector<ptr_vector<term>> m_decl2terms; // terms that use function f
ptr_vector<func_decl> m_decls;
@ -1202,22 +1215,27 @@ namespace qe {
hashtable<pair_t, pair_t::hash, pair_t::eq> diseqs;
expr_ref_vector result(m);
add_lits(lits);
auto const partitions = get_partition(mdl);
svector<pair_t> todo;
// TBD:
// M(f(a1 + 5)) != M(f(x1 + 5)) => a1 + 5 != x1 + 5 part of dcert.
// collect subterms in arith, put equal function subterms in certifiability set
for (expr* e : lits) {
expr* ne, *a, *b;
if (m.is_not(e, ne) && m.is_eq(ne, a, b) && (is_uninterp(a) || is_uninterp(b))) {
todo.push_back(pair_t(a, b));
diseqs.insert(pair_t(a, b));
}
else if (is_uninterp(e)) {
todo.push_back(pair_t(e, m.mk_false()));
diseqs.insert(pair_t(e, m.mk_false()));
}
else if (m.is_not(e, ne) && is_uninterp(ne)) {
todo.push_back(pair_t(ne, m.mk_true()));
}
diseqs.insert(pair_t(ne, m.mk_true()));
}
}
for (auto& p : todo) diseqs.insert(p);
for (auto& p : diseqs) todo.push_back(p);
auto const partitions = get_partition(mdl);
obj_map<expr, unsigned> term2pid;
unsigned id = 0;
for (auto const& vec : partitions) {