added back formula

forces.hpp

@@ -3,25 +3,34 @@
 #include "pedestrian.hpp"
 #include <cmath>
 
+// $\tau_{\alpha}$
 const double tau_alpha = 0.5;
 
+// $V^0_{\alpha \beta}$
 const double V0_AB = 2.1;
 
+// $\sigma$
 const double SIGMA = 0.3;
 
+// $U^0_{\alpha B}$
 const double U0_AB = 10.0;
 
+// $R$
 const double R = 0.2;
 
+// $c$
 const double c = 0.5;
 
+// $\varphi$
 const double phi = 100.0 / 180.0 * M_PI;
 
 const double cos_phi = cos(phi);
 
+// $\varDelta_{t}$
+// step size = 0.2 seconds
 const double delta_t = 2;
 
-const double dt = 0.01;
+const double dt = 0.001;
 
 // # Optional (forces.cpp: compute_repulsive_effects_from_pedestrians)
 // const double DISTANCE = 2.0;