Revert the changes. Going to add this as a new PR

flow/core/rewards.py

@@ -158,37 +158,6 @@ def min_delay_unscaled(env):
     cost = time_step * sum((v_top - vel) / v_top)
     return cost / (env.k.vehicle.num_vehicles + eps)
 
-def avg_delay_specified_vehicles(env, veh_ids):
-    """Calculates the average delay for a set of vehicles in the system
-    Parameters
-    ----------
-    env: flow.envs.Env
-        the environment variable, which contains information on the current
-        state of the system.
-    veh_ids: a list of the ids of the vehicles, for which we are calculating 
-             average delay
-    Returns
-    -------
-    float
-        average delay
-    """
-
-    vel = np.array(env.k.vehicle.get_speed(veh_ids))
-
-    vel[vel < -1e-6] = 0
-
-    sum = 0    
-    for edge in env.k.scenario.get_edge_list():
-        for veh_id in env.k.vehicle.get_ids_by_edge(edge):
-             v_top = env.k.scenario.speed_limit(edge)
-             sum += (v_top - env.k.vehicle.get_speed(veh_id)) / v_top
-    time_step = env.sim_step
-    try:
-        cost = time_step * sum
-        return cost / len(veh_ids)
-    except ZeroDivisionError:
-        return 0
-
 
 def penalize_standstill(env, gain=1):
     """A reward function that penalizes vehicle standstill