fixed index number

flatland/envs/rail_generators.py

@@ -684,8 +684,7 @@ def sparse_rail_generator(max_num_cities: int = 5, grid_mode: bool = False, max_
             number_of_out_rails = np.random.randint(1, min(rails_between_cities, nr_of_connection_points) + 1)
             start_idx = int((nr_of_connection_points - number_of_out_rails) / 2)
             for direction in range(4):
-                connection_slots = np.arange(connections_per_direction[direction]) - int(
-                    connections_per_direction[direction] / 2)
+                connection_slots = nr_of_connection_points - start_idx
                 for connection_idx in range(connections_per_direction[direction]):
                     if direction == 0:
                         tmp_coordinates = (
@@ -700,7 +699,7 @@ def sparse_rail_generator(max_num_cities: int = 5, grid_mode: bool = False, max_
                         tmp_coordinates = (
                             city_position[0] + connection_slots[connection_idx], city_position[1] - city_radius)
                     connection_points_coordinates_inner[direction].append(tmp_coordinates)
-                    if connection_idx in range(start_idx, start_idx + number_of_out_rails + 1):
+                    if connection_idx in range(start_idx, start_idx + number_of_out_rails):
                         connection_points_coordinates_outer[direction].append(tmp_coordinates)
 
             inner_connection_points.append(connection_points_coordinates_inner)