Added parameters

readme.md

@@ -39,20 +39,30 @@ use differential_equations::controller::PIController;
 use differential_equations::callback::stop;
 use differential_equations::problem::*;
 
-// Define the system
-fn derivative(_t: f64, y: Vector3<f64>) -> Vector3<f64> { y }
+// Define the system (parameters, derivative, and initial state)
+type Params = (f64, bool);
+let params = (34.0, true);
+
+fn derivative(t: f64, y: Vector3<f64>, p: &Params) -> Vector3<f64> {
+  if p.1 { -y } else { y * t }
+}
+
 let y0 = Vector3::new(1.0, 1.0, 1.0);
 
-let ode = ODE::new(&derivative, 0.0, 10.0, y0);
+// Set up the problem (ODE, Integrator, Controller, and Callbacks)
+let ode = ODE::new(&derivative, 0.0, 10.0, y0, params);
 let dp45 = DormandPrince45::new(1e-12_f64, 1e-5_f64);
 let controller = PIController::default();
 
 let value_too_high = Callback {
-    event: &|_: f64, y: SVector<f64,3>| { 10.0 - y[0] },
+  event: &|_: f64, y: Vector3<f64>, _: &Params| { 10.0 - y[0] },
     effect: &stop,
 };
 
+// Solve the problem
 let mut problem = Problem::new(ode, dp45, controller).with_callback(value_too_high);
 let solution = problem.solve();
+
+// Can interpolate solutions to whatever you want
 let interpolated_answer = solution.interpolate(8.2);
 ```