contractor default_strategy::build_contractor(box const & box,
scoped_vec<shared_ptr<constraint>> const & ctrs,
bool const complete,
SMTConfig const & config) const {
bool const use_cache = true;
// 1. Categorize constraints
vector<shared_ptr<nonlinear_constraint>> nl_ctrs;
vector<shared_ptr<ode_constraint>> ode_ctrs_rev;
vector<shared_ptr<generic_forall_constraint>> generic_forall_ctrs;
for (shared_ptr<constraint> const ctr : ctrs.get_reverse()) {
switch (ctr->get_type()) {
case constraint_type::Nonlinear: {
auto nl_ctr = dynamic_pointer_cast<nonlinear_constraint>(ctr);
nl_ctrs.push_back(nl_ctr);
break;
}
case constraint_type::ODE: {
auto ode_ctr = dynamic_pointer_cast<ode_constraint>(ctr);
ode_ctrs_rev.push_back(ode_ctr);
break;
}
case constraint_type::GenericForall: {
auto gf_ctr = dynamic_pointer_cast<generic_forall_constraint>(ctr);
generic_forall_ctrs.push_back(gf_ctr);
break;
}
case constraint_type::ForallT: {
// Do nothing
break;
}
default:
DREAL_LOG_FATAL << "Unknown Constraint Type: " << ctr->get_type() << " " << *ctr << endl;
}
}
vector<shared_ptr<ode_constraint>> ode_ctrs(ode_ctrs_rev);
reverse(ode_ctrs.begin(), ode_ctrs.end());
vector<contractor> ctcs;
ctcs.reserve(ctrs.size());
// 2.0 Build Sample Contractor
if (config.nra_sample > 0 && complete) {
ctcs.push_back(mk_contractor_sample(box, config.nra_sample, ctrs.get_vec()));
}
// 2.1 Build nonlinear contractors
vector<contractor> nl_ctcs;
for (auto const & nl_ctr : nl_ctrs) {
if (!nl_ctr->is_neq()) {
nl_ctcs.push_back(mk_contractor_ibex_fwdbwd(nl_ctr, use_cache));
} else {
// Case: != (not equal), do nothing
}
}
contractor nl_ctc = mk_contractor_seq(nl_ctcs);
ctcs.insert(ctcs.end(), nl_ctcs.begin(), nl_ctcs.end());
// 2.2. Build Polytope Contractor
if (config.nra_polytope) {
ctcs.push_back(mk_contractor_ibex_polytope(config.nra_precision, box.get_vars(), nl_ctrs));
}
// 2.3. Int Contractor
ctcs.push_back(mk_contractor_int(box));
// 2.4. Build generic forall contractors
for (auto const & generic_forall_ctr : generic_forall_ctrs) {
ctcs.push_back(mk_contractor_generic_forall(box, generic_forall_ctr));
}
if (complete && ode_ctrs.size() > 0) {
// Add ODE Contractors only for complete check
// 2.5. Build GSL Contractors (using CAPD4)
vector<contractor> ode_gsl_ctcs;
if (config.nra_ODE_sampling) {
// 2.5.1 Build Eval contractors
vector<contractor> eval_ctcs;
for (auto const & nl_ctr : nl_ctrs) {
eval_ctcs.push_back(mk_contractor_eval(nl_ctr, false));
}
contractor eval_ctc = mk_contractor_seq(eval_ctcs);
if (config.nra_parallel) {
vector<contractor> nl_ctcs2;
for (auto const & nl_ctr : nl_ctrs) {
if (!nl_ctr->is_neq()) {
nl_ctcs2.push_back(mk_contractor_ibex_fwdbwd(nl_ctr, false));
} else {
// Case: != (not equal), do nothing
}
}
contractor nl_ctc2 = mk_contractor_seq(nl_ctcs2);
for (auto const & ode_ctr : ode_ctrs) {
// Add Forward ODE Pruning (Underapproximation, using GNU GSL)
ode_gsl_ctcs.push_back(mk_contractor_gsl(box, ode_ctr, eval_ctc, ode_direction::FWD, false, config.nra_ODE_fwd_timeout));
ode_gsl_ctcs.push_back(nl_ctc2);
}
} else {
for (auto const & ode_ctr : ode_ctrs) {
// Add Forward ODE Pruning (Underapproximation, using GNU GSL)
ode_gsl_ctcs.push_back(mk_contractor_gsl(box, ode_ctr, eval_ctc, ode_direction::FWD, use_cache, config.nra_ODE_fwd_timeout));
ode_gsl_ctcs.push_back(nl_ctc);
}
}
}
// 2.6. Build ODE Contractors (using CAPD4)
vector<contractor> ode_capd4_fwd_ctcs;
vector<contractor> ode_capd4_bwd_ctcs;
for (auto const & ode_ctr : ode_ctrs) {
// 2.6.1. Add Forward ODE Pruning (Overapproximation, using CAPD4)
if (config.nra_ODE_cache) {
ode_capd4_fwd_ctcs.emplace_back(
mk_contractor_cache(
mk_contractor_try(
mk_contractor_seq(mk_contractor_capd_full(box, ode_ctr, ode_direction::FWD, config.nra_ODE_taylor_order, config.nra_ODE_grid_size, use_cache, config.nra_ODE_fwd_timeout),
nl_ctc))));
} else {
ode_capd4_fwd_ctcs.emplace_back(
mk_contractor_try(
mk_contractor_seq(
mk_contractor_capd_full(box, ode_ctr, ode_direction::FWD, config.nra_ODE_taylor_order, config.nra_ODE_grid_size, use_cache, config.nra_ODE_fwd_timeout),
nl_ctc)));
}
}
if (!config.nra_ODE_forward_only) {
// 2.6.2. Add Backward ODE Pruning (Overapproximation, using CAPD4)
for (auto const & ode_ctr : ode_ctrs_rev) {
if (config.nra_ODE_cache) {
ode_capd4_bwd_ctcs.emplace_back(
mk_contractor_cache(
mk_contractor_try(
mk_contractor_seq(
mk_contractor_capd_full(box, ode_ctr, ode_direction::BWD, config.nra_ODE_taylor_order, config.nra_ODE_grid_size, use_cache, config.nra_ODE_bwd_timeout),
nl_ctc))));
} else {
ode_capd4_bwd_ctcs.emplace_back(
mk_contractor_try(
mk_contractor_seq(
mk_contractor_capd_full(box, ode_ctr, ode_direction::BWD, config.nra_ODE_taylor_order, config.nra_ODE_grid_size, use_cache, config.nra_ODE_bwd_timeout),
nl_ctc)));
}
}
}
if (config.nra_ODE_sampling) {
if (config.nra_parallel) {
ctcs.push_back(mk_contractor_parallel_any(
mk_contractor_try_or(mk_contractor_throw_if_empty(mk_contractor_seq(ode_gsl_ctcs)),
mk_contractor_empty()),
mk_contractor_seq(mk_contractor_seq(ode_capd4_fwd_ctcs),
mk_contractor_seq(ode_capd4_bwd_ctcs))));
} else {
ctcs.push_back(
mk_contractor_try_or(
// Try Underapproximation(GSL) if it fails try Overapproximation(CAPD4)
mk_contractor_throw_if_empty(mk_contractor_seq(ode_gsl_ctcs)),
mk_contractor_seq(mk_contractor_seq(ode_capd4_fwd_ctcs),
mk_contractor_seq(ode_capd4_bwd_ctcs))));
}
} else {
ctcs.insert(ctcs.end(), ode_capd4_fwd_ctcs.begin(), ode_capd4_fwd_ctcs.end());
ctcs.insert(ctcs.end(), ode_capd4_bwd_ctcs.begin(), ode_capd4_bwd_ctcs.end());
}
}
if (complete) {
// 2.7 Build Eval contractors
vector<contractor> eval_ctcs;
for (auto const & nl_ctr : nl_ctrs) {
eval_ctcs.push_back(mk_contractor_eval(nl_ctr, use_cache));
}
return mk_contractor_seq(mk_contractor_fixpoint(default_strategy::term_cond, ctcs),
mk_contractor_seq(eval_ctcs));
} else {
return mk_contractor_fixpoint(default_strategy::term_cond, ctcs);
}
}
contractor nra_solver::build_contractor(box const & box, scoped_vec<constraint *> const &ctrs, bool const complete) {
vector<nonlinear_constraint const *> nl_ctrs;
vector<contractor> nl_ctcs;
nl_ctcs.reserve(ctrs.size());
vector<contractor> nl_eval_ctcs;
nl_eval_ctcs.reserve(ctrs.size());
vector<contractor> ode_ctcs;
ode_ctcs.reserve(ctrs.size());
// Add contractor_sample if --sample option is used
if (config.nra_sample > 0 && complete) {
nl_ctcs.push_back(mk_contractor_sample(config.nra_sample, ctrs.get_vec()));
}
for (constraint * const ctr : ctrs) {
if (ctr->get_type() == constraint_type::Nonlinear) {
nonlinear_constraint const * const nl_ctr = dynamic_cast<nonlinear_constraint *>(ctr);
if (nl_ctr->get_numctr()) {
nl_ctcs.push_back(mk_contractor_ibex_fwdbwd(box, nl_ctr));
nl_ctrs.push_back(nl_ctr);
} else {
// This is identity, do nothing
}
nl_eval_ctcs.push_back(mk_contractor_eval(box, nl_ctr));
#ifdef SUPPORT_ODE
} else if (ctr->get_type() == constraint_type::ODE) {
// TODO(soonhok): add heuristics to choose fwd/bwd
// TODO(soonhok): perform ODE only for complete check
ode_ctcs.emplace_back(
mk_contractor_try(
mk_contractor_capd_fwd_full(box, dynamic_cast<ode_constraint *>(ctr), config.nra_ODE_taylor_order, config.nra_ODE_grid_size)));
ode_ctcs.emplace_back(
mk_contractor_try(
mk_contractor_capd_bwd_full(box, dynamic_cast<ode_constraint *>(ctr), config.nra_ODE_taylor_order, config.nra_ODE_grid_size)));
#endif
}
}
if (config.nra_polytope) {
nl_ctcs.push_back(mk_contractor_ibex_polytope(config.nra_precision, nl_ctrs));
}
nl_ctcs.push_back(mk_contractor_int());
// Add contractor_sample if --sample option is used
if (config.nra_aggressive > 0 && complete) {
nl_ctcs.push_back(mk_contractor_sample(config.nra_aggressive, ctrs.get_vec()));
}
auto term_cond = [this](dreal::box const & old_box, dreal::box const & new_box) {
if (new_box.max_diam() < config.nra_precision) {
return true;
}
double const threshold = 0.01;
// If there is a dimension which is improved more than
// threshold, we stop the current fixed-point computation.
bool is_corner_case = true;
for (unsigned i = 0; i < old_box.size(); i++) {
double const new_box_i = new_box[i].diam();
double const old_box_i = old_box[i].diam();
if (new_box_i == numeric_limits<double>::infinity()) {
continue;
}
if (old_box_i == 0) {
// The i-th dimension was already a point, nothing to improve.
continue;
}
double const improvement = 1 - new_box_i / old_box_i;
assert(!std::isnan(improvement));
if (improvement >= threshold) {
return false;
} else {
is_corner_case = false;
}
}
if (is_corner_case && new_box == old_box) {
// We only do the equality check if it's a corner case
// where every dimension has either [ENTIRE] or a point
// value.
return false;
}
return true;
};
return mk_contractor_fixpoint(term_cond, nl_ctcs, ode_ctcs, nl_eval_ctcs);
}