ode_solver::ODE_result ode_solver::simple_ODE_backward(IVector & X_0, IVector const & X_t, interval const & T,
IVector const & inv, vector<IFunction> & funcs) {
// X_0 = X_0 \cup (X_t - + (d/dt Inv) * T)
for (int i = 0; i < X_0.dimension(); i++) {
interval & x_0 = X_0[i];
interval const & x_t = X_t[i];
IFunction & dxdt = funcs[i];
for (Enode * par : m_pars) {
double lb = get_lb(par);
double ub = get_ub(par);
string name = par->getCar()->getName();
dxdt.setParameter(name, interval(lb, ub));
}
try {
interval const new_x_0 = x_t - dxdt(inv) * T;
if (!intersection(new_x_0, x_0, x_0)) {
DREAL_LOG_INFO << "Simple_ODE: no intersection for X_0";
return ODE_result::UNSAT;
}
} catch (exception& e) {
DREAL_LOG_INFO << "Exception in Simple_ODE: " << e.what();
}
}
// update
IVector_to_varlist(X_0, m_0_vars);
return ODE_result::SAT;
}
void ode_solver::IVector_to_varlist(IVector const & v, vector<Enode*> & vars) {
for (auto i = 0; i < v.dimension(); i++) {
double lb = get_lb(vars[i]);
double ub = get_ub(vars[i]);
if (lb < v[i].leftBound())
set_lb(vars[i], v[i].leftBound());
if (ub > v[i].rightBound())
set_ub(vars[i], v[i].rightBound());
}
}
void printSample(const double &t, const IVector &x)
{
cout.setf(ios::scientific);
cout.setf(ios::showpos);
cout.precision(10);
cout << t << " ";
for(int i=0; i<x.dimension(); ++i)
cout << x[i].leftBound() << " " << x[i].rightBound() << " ";
cout << endl;
}
// Take an intersection of v and inv.
// If there is no intersection, return false.
bool ode_solver::check_invariant(IVector & v, IVector const & inv) {
if (!intersection(v, inv, v)) {
DREAL_LOG_INFO << "invariant violated!";
for (auto i = 0; i < v.dimension(); i++) {
if (v[i].leftBound() < inv[i].leftBound() || v[i].rightBound() > inv[i].rightBound()) {
DREAL_LOG_INFO << "inv[" << i << "] = " << inv[i];
DREAL_LOG_INFO << " v[" << i << "] = " << v[i];
}
}
return false;
}
return true;
}
