Change API of dsp/ode.hpp

include/dsp/ode.hpp

@@ -3,10 +3,14 @@
 
 namespace rack {
 
-typedef void (*stepCallback)(float x, const float y[], float dydt[]);
+/** The callback function `f` in each of these stepping functions must have the signature
+	void f(float x, const float y[], float dydt[])
+A capturing lambda is ideal for this.
+*/
 
-/** Solve an ODE system using the 1st order Euler method */
-inline void stepEuler(stepCallback f, float x, float dx, float y[], int len) {
+/** Solves an ODE system using the 1st order Euler method */
+template<typename F>
+void stepEuler(float x, float dx, float y[], int len, F f) {
 	float k[len];
 
 	f(x, y, k);
@@ -15,8 +19,28 @@ inline void stepEuler(stepCallback f, float x, float dx, float y[], int len) {
 	}
 }
 
-/** Solve an ODE system using the 4th order Runge-Kutta method */
-inline void stepRK4(stepCallback f, float x, float dx, float y[], int len) {
+/** Solves an ODE system using the 2nd order Runge-Kutta method */
+template<typename F>
+void stepRK2(float x, float dx, float y[], int len, F f) {
+	float k1[len];
+	float k2[len];
+	float yi[len];
+
+	f(x, y, k1);
+
+	for (int i = 0; i < len; i++) {
+		yi[i] = y[i] + k1[i] * dx / 2.f;
+	}
+	f(x + dx / 2.f, yi, k2);
+
+	for (int i = 0; i < len; i++) {
+		y[i] += dx * k2[i];
+	}
+}
+
+/** Solves an ODE system using the 4th order Runge-Kutta method */
+template<typename F>
+void stepRK4(float x, float dx, float y[], int len, F f) {
 	float k1[len];
 	float k2[len];
 	float k3[len];
@@ -26,14 +50,14 @@ inline void stepRK4(stepCallback f, float x, float dx, float y[], int len) {
 	f(x, y, k1);
 
 	for (int i = 0; i < len; i++) {
-		yi[i] = y[i] + k1[i] * dx / 2.0;
+		yi[i] = y[i] + k1[i] * dx / 2.f;
 	}
-	f(x + dx / 2.0, yi, k2);
+	f(x + dx / 2.f, yi, k2);
 
 	for (int i = 0; i < len; i++) {
-		yi[i] = y[i] + k2[i] * dx / 2.0;
+		yi[i] = y[i] + k2[i] * dx / 2.f;
 	}
-	f(x + dx / 2.0, yi, k3);
+	f(x + dx / 2.f, yi, k3);
 
 	for (int i = 0; i < len; i++) {
 		yi[i] = y[i] + k3[i] * dx;
@@ -41,7 +65,7 @@ inline void stepRK4(stepCallback f, float x, float dx, float y[], int len) {
 	f(x + dx, yi, k4);
 
 	for (int i = 0; i < len; i++) {
-		y[i] += dx * (k1[i] + 2.0 * k2[i] + 2.0 * k3[i] + k4[i]) / 6.0;
+		y[i] += dx * (k1[i] + 2.f * k2[i] + 2.f * k3[i] + k4[i]) / 6.f;
 	}
 }
 

include/util/common.hpp

@@ -116,14 +116,14 @@ Example:
 		fclose(file);
 	});
 */
-template <typename F>
+template<typename F>
 struct DeferWrapper {
 	F f;
 	DeferWrapper(F f) : f(f) {}
 	~DeferWrapper() { f(); }
 };
 
-template <typename F>
+template<typename F>
 DeferWrapper<F> deferWrapper(F f) {
 	return DeferWrapper<F>(f);
 }