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Re: [sumo-user] vehicle parameters for the current step
Have you checked the actual value of sigma being used by the vehicles in the type parameter dialog of sumo-gui?

Am Mi., 22. Feb. 2023 um 14:38 Uhr schrieb Mahima <mahima13@xxxxxxxxx>:
But I am keeping sigma = 0.

For sigma 0, vMax should be used as next speed and not vDawdle.
vDawdle = MAX2(vMin, dawdle2(vMax, sigma, veh->getRNG()));

On Wed, Feb 22, 2023 at 4:32 PM Jakob Erdmann <namdre.sumo@xxxxxxxxx> wrote:
> This randomness calculation should be off when we use --random false.
No. This is not what option --random does.
As long as vehicles have sigma > 0 (default is 0.5) there will be random speed fluctuations between your partitions.

Am Mi., 22. Feb. 2023 um 14:23 Uhr schrieb Mahima <mahima13@xxxxxxxxx>:
Hi,

We have developed a parallel framework over SUMO. When I am copying vehicles from one partition to another. With the vehicles I am also copying the following lane change parameters. I am keeping sigma 0, --random false and same seed value for all the partitions and sequential SUMO.

"laneChangeModel.speedGainProbabilityRight"
"laneChangeModel.keepRightProbability"
"laneChangeModel.lookAheadSpeed"

After adding vehicles in the next partition, I am also moving them for the desired position in the current step and setting speed for the current step.
i am calculating the current step speed as follows:

double vthis=LastTimestepSpeed+ACCEL2SPEED(LastTimestepAcceleration);
Or if the vehicle has a Leader...then with the follow speed.

But if I compare travel time of this parallel framework with sequential SUMO, I am getting an accuracy error.

I have found that patchSpeedBeforeLC is calculating some different speed which is causing randomness.

  vDawdle = MAX2(vMin, dawdle2(vMax, sigma, veh->getRNG()));

This randomness calculation should be off when we use --random false.

Thanks,
Mahima

On Wed, Feb 22, 2023 at 1:41 PM Jakob Erdmann <namdre.sumo@xxxxxxxxx> wrote:
The function getStopSpeed is not only used for <stop> elements but also for approaching intersections where a vehicle needs to come to a stop.
From your description it is not clear what exactly you are doing and why you are observing a differences between some speeds and some other speeds.


Am Di., 21. Feb. 2023 um 14:24 Uhr schrieb Mahima <mahima13@xxxxxxxxx>:
Thanks for your reply.
Yes, sigma is already set as 0. The only difference I can see is the stop speed (getStopSpeed) is different.

How can I set the stop speed of a vehicle? Is it by using  libsumo::Vehicle::setStopParameter? But then I need to define the stop first...correct?

Thanks.

On Sun, Feb 19, 2023 at 3:28 PM Jakob Erdmann <namdre.sumo@xxxxxxxxx> wrote:
> Why does the vehicle need information about the vehicle on the previous edge for the car following model speed calculation?
This is likely a misunderstanding. What gives you that impression?

> How can I set the car following model parameters from the previous partition to the master partition such that it gives the same speed calculation of a vehicle?
The default car-following model doesn't have internal state so it should reproduce the same behavior when faced with the same situation (distance, ego speed, leader speed, deceleration capabilities, speedFactor). A possible cause for difference is the random component (sigma). You can check whether the differences are due to randomness by setting sigma=0.

Am So., 19. Feb. 2023 um 11:36 Uhr schrieb Mahima <mahima13@xxxxxxxxx>:
Hi,

Why does the vehicle need information about the vehicle on the previous edge for the car following model speed calculation?
How can I set the car following model parameters from the previous partition to the master partition such that it gives the same speed calculation of a vehicle?

Thanks

On Wed, Sep 28, 2022 at 9:48 AM Jakob Erdmann <namdre.sumo@xxxxxxxxx> wrote:
using getParameter / setParameter with the following values should be enough for the default lanechangem model:
"laneChangeModel.speedGainProbabilityRight"
"laneChangeModel.keepRightProbability"
"laneChangeModel.lookAheadSpeed"

Am Mo., 26. Sept. 2022 um 09:58 Uhr schrieb Mahima <mahima13@xxxxxxxxx>:
When I am copying a vehicle from one partition to the other on the same lane and position as it was on the previous partition, but in the current timestep if there was a lane change decision in the previous partition......which lane change API or flag will give me the same lane change decision in the master partition.
In this scenario, I am already making sure that the neighbouring vehicles for this vehicle are the same as on the previous partition. 

Please suggest.

On Mon, Sep 26, 2022 at 9:39 AM Jakob Erdmann <namdre.sumo@xxxxxxxxx> wrote:

Am So., 25. Sept. 2022 um 11:02 Uhr schrieb Mahima <mahima13@xxxxxxxxx>:
Hi,

Is there any way to read the vehicle's speed, lane and position in the current timestep?

libsumo::Vehicle::getLanePosition
libsumo::Vehicle::getSpeed
All these APIs, give information about the last timestep.

Thanks
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