- #1

- 31

- 2

Thanks!

Code:

```
void verlet(System& system, Trajectory& trajectory, double delta){
long n = trajectory.get_number_of_rows();
long n_bodies = system.get_number_of_bodies();
double delta2 = pow(delta, 2);
std::cout << "Starting integrator." << std::endl;
for (int i = 0; i < n; ++i) {
if(i == 0){
std::vector<Vector3 > x0 = system.get_positions();
std::vector<Vector3> v0 = system.get_velocities();
trajectory.set_position(x0, v0);
system.set_positions(x0);
system.set_velocities(v0);
}
else {
std::vector<Vector3> x0 = trajectory.get_positions_at_index(i-1);
std::vector<Vector3> v0 = trajectory.get_velocities_at_index(i-1);
std::vector<Vector3> a0 = system.get_accelerations();
std::vector<Vector3> x1 {};
for (long j = 0; j < n_bodies; ++j) {
x1.emplace_back(x0[j] + v0[j] * delta + delta2 * 0.5 * a0[j]);
}
system.set_positions(x1);
std::vector<Vector3 > a1 = system.get_accelerations();
std::vector<Vector3 > v1;
for (long k = 0; k < n_bodies; ++k) {
v1.emplace_back(v0[k] + 0.5 *( a0[k] + a1[k]) * delta );
}
system.set_velocities(v1);
trajectory.set_position(x1, v1);
}
}
std::cout << "Integration finished." << std::endl;
}
```