Thank you so much for your answer Jakob! To answer your question (Just for clarity: are you comparing simulation runs with different values of --seed?): Yes, that's exactly what I was trying to do.
With your suggestion, I was able to see the randomness that I was looking for! Thanks! ________________________________ From: sumo-user <[email protected]> on behalf of Jakob Erdmann <[email protected]> Sent: Thursday, March 4, 2021 2:05 AM To: Sumo project User discussions <[email protected]> Subject: Re: [sumo-user] Using random seed 1) sigma (for the default carFollowModel) controls random slow-downs. Vehicles drive slower than their preferred/optimum speed in any given situation. This leads to a "ragged" look of the speed curve even in free flow conditions. In contrast, speedDev controls the deviation of preferred speed. This set a fixed random speedFactor value for each vehicle so in the absense of sigma each vehicle would drive with a constant speed in free flow but each vehicle would do this at a different speed. 2) departure time is only affected directly if option --random-depart-offset is set. You may see some effects from sigma and speedDev due to departDelay-interactions at high density though. Vehilce type drawing should be affected though. Just for clarity: are you comparing simulation runs with different values of --seed? Am Mi., 3. März 2021 um 20:10 Uhr schrieb Bae, Jong In <[email protected]<mailto:[email protected]>>: Hello, I've been working on using random seed and had some questions. I'm having trouble seeing the difference between before and after I assigned a random seed value. I attached a screenshot of my sumocfg file just in case my syntax is incorrect. 1. How is sigma different than speedDev? 2. According to this link (https://sumo.dlr.de/docs/Simulation/Randomness.html#random_number_generation_rng<https://nam12.safelinks.protection.outlook.com/?url=https%3A%2F%2Fsumo.dlr.de%2Fdocs%2FSimulation%2FRandomness.html%23random_number_generation_rng&data=04%7C01%7Cjbae42%40gatech.edu%7Cdfc76b752c5848c62acf08d8dedbe6bc%7C482198bbae7b4b258b7a6d7f32faa083%7C0%7C0%7C637504383337471464%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=iRrurE6yUZvKuDMS796hFXnr7qFwc9O9V9FZ%2B6tHASo%3D&reserved=0>), I should be seeing randomness in loading vehicles. To my understanding, I should expect to see randomness in the following two areas: (1) the entry time when vehicles enter the scenario should be different and (2) the sequence in vehicle type in vTypeDistribution should be different. However, I am not seeing any difference in the vehicles' entry time or the sequence in vehicle type in vTypeDistribution. But I am seeing randomness in speed (tested with only one vehicle also). So I think the random seed is in effect. I'm just not sure why I am not seeing randomness in the two areas mentioned above. Thank you so much for the help! _______________________________________________ sumo-user mailing list [email protected]<mailto:[email protected]> To unsubscribe from this list, visit https://www.eclipse.org/mailman/listinfo/sumo-user<https://nam12.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.eclipse.org%2Fmailman%2Flistinfo%2Fsumo-user&data=04%7C01%7Cjbae42%40gatech.edu%7Cdfc76b752c5848c62acf08d8dedbe6bc%7C482198bbae7b4b258b7a6d7f32faa083%7C0%7C0%7C637504383337481421%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=USjTFpE1DyPN6NVcchbdYIRVUKAe3UOQqNEQgNmceEE%3D&reserved=0>
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