Re: [sumo-user] Need Assistance with TraCI Constants and Subscription Do

[Hriday Sanghvi <sanghvih@xxxxxx>]

Thank you for the advice Mirko,

One more question. Can I use tc.LCA_CHANGE_TO_HELP with any domain? Or is that also used internally as a constant? Would love to use it as an additional metric, seeing how many times a vehicle changes its lane to help another vehicle (if that's what it's for).

Sincerely,

Hriday

On Thu, 21 Dec 2023 at 08:16, Mirko Barthauer <m.barthauer@xxxxxxxxxxx> wrote:

Dear Hriday,

 

you can find a list of which values can be retrieved in each domain in the docs. tc.VAR_ALLOWED_SPEED is for vehicles (max speed on lane is tc.VAR_MAXSPEED). There is no getter for tc.VAR_PREV_SPEED as this a value provided by the user anyway. The remaining ones you listed do not belong to the variables to retrieve but are simple constants used in some TraCI functions.

 

Best regards

Mirko

 

 

 

-----Original-Nachricht-----

Betreff: [sumo-user] Need Assistance with TraCI Constants and Subscription Domains in SUMO

Datum: 2023-12-20T17:41:22+0100

Von: "Hriday Sanghvi via sumo-user" <sumo-user@xxxxxxxxxxx>

An: "Sumo project User discussions" <sumo-user@xxxxxxxxxxx>

 

 

 

Hello, my version info:

 

TraCI VERSION 21
'SUMO 79d8ebc13' (updated today)

Ubuntu 18.04.6 LTS

 

On seeing traci.exceptions.TraCIException: Could not add subscription. Get Vehicle Variable: unsupported variable 0x23 specified for some traci constants I was trying to use for subscriptions, I realized that maybe the domain I was using was wrong. So I figured the domain out for some of them like tc.VAR_COLLISIONS is used in traci.simulation.subscribe(), tc.VAR_ACCEL in traci.vehicletype.subscribe() tc.VAR_SPEED in traci.vehicle.subscribe() - all by trial and error/guesswork. I still can't figure out the correct domains for the following constants:

tc.VAR_ALLOWED_SPEED (assumed it was lane domain, but nope)
tc.VAR_PREV_SPEED (should have been vehicle domain, but nope)

However, for some constants:

tc.LCA_WANTS_LANECHANGE,
tc.LCA_WANTS_LANECHANGE_OR_STAY,
tc.LANE_CHANGES,
tc.LANE_ALLOWED,
tc.LANECHANGE_LEFT,
tc.LANECHANGE_RIGHT,

the error is very different:
Traceback (most recent call last):
File "code_tester.py", line 38, in <module>
tc.LCA_WANTS_LANECHANGE, # (or whatever the constant is in the list)
File "/home/alice/sumo/tools/traci/domain.py", line 188, in subscribe
self._connection._subscribe(self._subscribeID, begin, end, objectID, varIDs, parameters)
File "/home/alice/sumo/tools/traci/connection.py", line 295, in _subscribe
result = self._sendCmd(cmdID, (begin, end), objID, format, *args)
File "/home/alice/sumo/tools/traci/connection.py", line 212, in _sendCmd
packed = self._pack(format, *values)
File "/home/alice/sumo/tools/traci/connection.py", line 170, in _pack
packed += struct.pack("!B", int(v))
struct.error: ubyte format requires 0 <= number <= 255

How can I fix this from my end? I have attached the minimum code to reproduce this as a zip. P.S. The reason I have to use TraCI for this case is because that's the only way I have been able to use the GUI for years.

 

Thank you.

 

Sincerely,

Hriday