double nonlinear_constraint::eval_error(box const & b) const {
// Construct iv from box b
if (get_var_array().size() > 0) {
ibex::IntervalVector iv(get_var_array().size());
for (int i = 0; i < get_var_array().size(); i++) {
iv[i] = b[get_var_array()[i].name];
DREAL_LOG_DEBUG << get_var_array()[i].name << " = " << iv[i];
}
return eval_error(iv);
} else {
ibex::IntervalVector iv(1);
return eval_error(iv);
}
}
void contractor_generic_forall::handle_disjunction(contractor_status & cs, vector<Enode *> const &vec, bool const p) {
DREAL_LOG_DEBUG << "contractor_generic_forall::handle_disjunction" << endl;
unordered_set<Enode *> forall_vars;
for (Enode * e : vec) {
std::unordered_set<Enode *> const & vars = e->get_forall_vars();
forall_vars.insert(vars.begin(), vars.end());
}
unordered_map<Enode*, ibex::Interval> subst;
if (!forall_vars.empty()) {
// Step 2. Find a counter-example
// Solve(¬ l_1 ∧ ¬ l_2 ∧ ... ∧ ¬ l_n)
//
// Make each ¬ l_i as a contractor ctc_i
// Make a fixed_point contractor with ctc_is.
// Pass it to icp::solve
box counterexample = find_CE(cs.m_box, forall_vars, vec, p, cs.m_config);
if (counterexample.is_empty()) {
// Step 2.1. (NO Counterexample)
// Return B.
DREAL_LOG_DEBUG << "handle_disjunction: no counterexample found." << endl
<< "current box = " << endl
<< cs.m_box << endl;
return;
} else {
// Step 2.2. (There IS a counterexample C)
//
// Using C, prune B.
//
// We've found a counterexample (c1, c2) where ¬ f(c1, c2) holds
// Prune X using a point 'y = c2'. (technically, a point in c2, which is an interval)
subst = make_subst_from_value(counterexample, forall_vars);
}
}
// Step 3. Compute B_i = prune(B, l_i)
// Update B with ∨ B_i
// i
thread_local static vector<box> boxes;
boxes.clear();
auto vars = cs.m_box.get_vars();
unordered_set<Enode*> const var_set(vars.begin(), vars.end());
for (Enode * e : vec) {
if (!e->get_exist_vars().empty()) {
lbool polarity = p ? l_True : l_False;
if (e->isNot()) {
polarity = !polarity;
e = e->get1st();
}
auto ctr = make_shared<nonlinear_constraint>(e, var_set, polarity, subst);
if (ctr->get_var_array().size() == 0) {
auto result = ctr->eval(cs.m_box);
if (result.first != false) {
boxes.emplace_back(cs.m_box);
}
} else {
contractor ctc = mk_contractor_ibex_fwdbwd(ctr);
contractor_status bt(cs.m_box, cs.m_config);
ctc.prune(bt);
cs.m_output.union_with(bt.m_output);
unordered_set<shared_ptr<constraint>> const & used_ctrs = bt.m_used_constraints;
cs.m_used_constraints.insert(used_ctrs.begin(), used_ctrs.end());
boxes.emplace_back(bt.m_box);
}
}
}
if (boxes.size() > 0) {
cs.m_box = hull(boxes);
} else {
cs.m_box.set_empty();
}
return;
}
