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Re: [sumo-user] Running different scenarios with the same random seeds

I looked at your simulation and observed the following:
- the number of left-turns is mostly irrelevant to delay since the total flow is low enough to allow for easy merging
- the difference in delay is dominated by the flow the southern approach.
All the extra vehicles turning left at cluster_n07_n24 make a right-turn at junction n08 thereby creating gaps for the traffic from the south.
The results do look plausible to me.
Possibly, the vissim junction model allows for more aggressive entering.

regards,
Jakob



Am Mo., 21. Okt. 2019 um 23:49 Uhr schrieb Usama Shahdah <usama.elrawy@xxxxxxxxx>:
Hi Jakob,

Thank you so much for your replay.

1) For the random seeds issues, I found that I used to set the option (--random=true). That's why I get different results for the same seeds. I did not notice that --random --> Initialises the random number generator with the current system time; default: false.
 
Now when setting the same random seed (with --random=false), I get exactly the same results.

2) The calculated average delay is based on this thread: https://www.eclipse.org/lists/sumo-user/msg01176.html

3) The calculated delay (between 1800 sec. and 5400 sec.) is similar to the TimeLoss value as in: https://sumo.dlr.de/docs/Simulation/Output.html#aggregated_traffic_measures

4) I ran sumo and duarouter using three different random seeds for both the 10% LT and 30% LT scenarios, but still getting the wrong results. I am not sure what I am doing wrong, so I attached the files I used, along with the results I got from VISSIM.

Please note that I used the w99 cfm in the attached files. I did used different CFMs before, but still get the same odd results.

Please note that, I did changed the visibility for all connectors to 150 m.

It is also worth noting that the SSM output files in the case of 30% LT is larger than in the case of the 10%LT.

Any help in what I am doing wrong will be much appreciated.
(Note: to be able to attach the files, the extension of All bat files is changed to( .bat.2), so please remove the .2 to run or access the original bat file)

Best regards,
Usama

Hello,
I'm not sure whether I'm understanding you correctly but maybe this helps:
- you can set the random seed for sumo, duarouter, randomTrips etc.
explicitly with the option --seed
- two runs of the same application with the same seed will behave in the
exact same way
- If the delays between two sets of scenarios are implausible, please try
to narrow down whether that is due to invalid vehicle behavior or invalid
measures. You could check against the total timeLoss computed by sumo (
https://sumo.dlr.de/docs/Simulation/Output.html#aggregated_traffic_measures,
https://sumo.dlr.de/docs/Simulation/Output/TripInfo.html#generated_output)

regards,
Jakob

Am Fr., 18. Okt. 2019 um 17:26 Uhr schrieb Usama Shahdah <
usama.elrawy@xxxxxxxxx>:

> Hi Michael,
>>
> First of all thanks for your reply.
>
> what I usually do is running sumo 10 times or more with different random
> seeds for duarouter to ensure random trips and different random numbers for
> sumo. Then estimate the average delay for each run then get the average
> delay for the ten runs. So I am using random seeds when running duarouter.
>
> I do not think using only the meanTimeLossWithin alone is correct and this
> is based on my understanding of E3 output file here:
> https://sumo.dlr.de/docs/Simulation/Output/Multi-Entry-Exit_Detectors_(E3).html
>
> as it mentioned that the meanTimeLossWithin is The average time loss
> collected by vehicles that have entered but not yet left the area during
> the written interval.
>
> Anyway after comparing the results when using 10% LT and 30% LT of the
> approach demand for the 10 runs, the delay for the 30% LT is always less
> than the 10% LT whatever I change the cfm and lane change parameters. And
> this does not make sense at all. To confirm that there is something wrong I
> simulated the same Uturn intersection in vissim for 10 runs and the results
> were making sense, as the 30%LT scenarios always give higher delay than the
> 10% scenarios.
>
> in vissim if I run the simulation with the same exact random seed for
> let's say 5 runs, I will get exactly the same results for of course the
> same traffic volume and same scenario.
>
> so my question is: it is possible to use the same random seed to do the
> simulation, so I can compare different scenarios with exactly the same
> random seeds for the 10 runs. If course every run will have different
> random seed.
>
> In sumo, the random seed used is a starting seed to use, so when using
> this same seed I got different results for the same traffic volume and same
> scenario.
>
> Hopefully I am clear this time.
>
> Regards,
> Usama
>
> Hi,
>
>> I am not sure how duarouter can help here. It does not calculate any
>> delays. I think you should rather run many simulations with different
>> random seeds and then do statistics. Also why can't you use
>> meanTimeLossWithin directly?
>>
>> Best regards,
>> Michael
>>
>> Am 16.10.19 um 22:39 schrieb Usama Shahdah:
>> > Hi:
>> >
>> > I would like to compare different scenarios (for Unturn intersections)
>> > with different left turn movements (eg. 10%, 20% and 30% LT) using the
>> > same random seed for both duarouter and sumo simulation.
>> >
>> > Is there a way to do so? and how?
>> >
>> > The issue I have right now is that for high traffic volumes (1250
>> > veh/hr/ approach) and above, the delay for 30% LT is lower than for
>> > 10%LT, which does not make sense to me.
>> >
>> > Please note that I am using E3 detector to estimate the delay, and I am
>> > using the following formula to do so:
>> >
>> > Average Delay= (sum[meanTimeLoss * vehicleSum]?+ Sum[meanTimeLossWithin
>> > * vehicleSumWithin]) /( vehicleSum + vehicleSumWithin)
>> >
>> > Any help will be appreciated.
>> >
>> > Regards,
>> > Usama

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