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Re: [sumo-user] vehicle parameters for the current step
Yes, I have checked sigma is 0.

Do we have a similar function in libsumo like processLinkApproaches() that can give me vSafe? 

Just found out that to calculate speed for the next step, sumo calculates using processLinkApproaches() and NOT as follows. 
double vthis=LastTimestepSpeed+ACCEL2SPEED(LastTimestepAcceleration);

Thanks for your help.

On Wed, Feb 22, 2023 at 4:41 PM Jakob Erdmann <namdre.sumo@xxxxxxxxx> wrote:
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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