diff --git a/lib/integrator.py b/lib/integrator.py
index 1cd5c6c..d148160 100755
--- a/lib/integrator.py
+++ b/lib/integrator.py
@@ -16,9 +16,11 @@ def dp_dt(m_array, q_array):
     """
     dp_array = np.zeros(q_array.shape)
     for i in range(q_array.shape[0]):
-        m_j = np.delete(m_array, i)
         q_j = np.delete(q_array, i, 0)
-        dp_array = -m_array[i]*np.sum((m_j/np.sum((q_j-q_array[i])**3, axis=1)).reshape((q_j.shape[0],1))*(q_j-q_array[i]), axis=0)
+        m_j = np.delete(m_array, i).reshape((q_j.shape[0],1))
+        dp_array[i] = -m_array[i]*np.sum(m_j/np.sum(np.sqrt(np.sum((q_j-q_array[i])**2, axis=0)))**3*(q_j-q_array[i]), axis=0)
+    dp_array[np.isnan(dp_array)] = 0.
+    print(dp_array)
     return dp_array
 
 def frogleap(duration, step, m_array, q_array, p_array, display=False):
@@ -38,11 +40,15 @@ def frogleap(duration, step, m_array, q_array, p_array, display=False):
         q_array, p_array = q_array , p_array - step*dp_dt(m_array, q_array)
         # half-step drift
         q_array, p_array = q_array + step/2*p_array/m_array , p_array
+        #print(p_array)
+        
+        # In center of mass frame
+        q_cm = np.sum(m_array.reshape((q_array.shape[0],1))*q_array, axis=0)/m_array.sum()
+        q_array -= q_cm
 
         if display:
             # display progression
-            q_cm = np.sum(m_array.reshape((q_array.shape[0],1))*q_array, axis=0)/m_array.sum()
-            d.on_running(q_array[:,0]-q_cm[0], q_array[:,1]-q_cm[1])
-            time.sleep(0.1)
+            d.on_running(q_array[:,0], q_array[:,1])
+            time.sleep(0.01)
 
     return q_array, p_array
diff --git a/lib/plots.py b/lib/plots.py
index ee1e6d9..a1e99d5 100755
--- a/lib/plots.py
+++ b/lib/plots.py
@@ -11,6 +11,8 @@ class DynamicUpdate():
     min_x = -10
     max_x = 10
 
+    plt.ion()
+
     def on_launch(self):
         #Set up plot
         self.figure, self.ax = plt.subplots()
diff --git a/main.py b/main.py
index 9d56173..2de7042 100755
--- a/main.py
+++ b/main.py
@@ -6,7 +6,7 @@ from lib.integrator import frogleap
 
 def main():
     #initialisation
-    m = np.array([100, 2, 2])
+    m = np.array([1e5, 1, 1])
 
     x1 = np.array([0, 0, 0])
     x2 = np.array([1, 0, 0])
@@ -14,11 +14,11 @@ def main():
     q = np.array([x1, x2, x3])
 
     v1 = np.array([0, 0, 0])
-    v2 = np.array([1, 0, 0])
-    v3 = np.array([1, 0, 0])
+    v2 = np.array([0, 0, 0])
+    v3 = np.array([0, 0, 0])
     p = m*np.array([v1, v2, v3])
 
-    q, p = frogleap(10, 1, m, q, p, display=True)
+    q, p = frogleap(10, 0.01, m, q, p, display=True)
     return 0
 
 if __name__ == '__main__':