fixed bug in perimeter calculation

convergence_extension/perimeter_long_axis.py

@@ -7,7 +7,11 @@ from scipy.spatial import ConvexHull
 def perimeter(X, Y):
     points = np.column_stack((X, Y))
     hull = ConvexHull(points)
-    value = sum(np.linalg.norm(points[hull.vertices[i]] - points[hull.vertices[(i+1)%len(hull.vertices)]]) for i in range(len(hull.vertices)))
+    N = len(hull.vertices)
+    value = 0
+    for i in range(N):
+        value += np.linalg.norm(points[hull.vertices[i]] - points[hull.vertices[(i+1)%N]]) 
+        # The (i+1)%N part ensures that after the last vertex, we go back to the first vertex, creating a closed loop
     return value
 
 def long_axis(x, y):