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Question: direct link between time step size and platoon size #50

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EwoutH opened this issue Mar 26, 2024 · 2 comments
Closed

Question: direct link between time step size and platoon size #50

EwoutH opened this issue Mar 26, 2024 · 2 comments

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@EwoutH
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EwoutH commented Mar 26, 2024

I noticed that the time step size (DELTAT) is directly linked to the platoon size (DELTAN) through the reaction time (REACTION_TIME), as shown in the initialization DELTAT = REACTION_TIME * DELTAN.

I'm curious why this is modelled this way, could you clarify the rationale behind this direct linkage between time step size and platoon size?

@toruseo
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toruseo commented Mar 27, 2024

There is a theoretical reason. In this way, we can compute the exact solution of KW model (the underlying traffic flow model of UXsim) efficiently. In short, it eliminates numerical errors. If we use different setting, it will induce so-called numerical diffusion or instability.

If you want know the details, you need to read a paper: http://www.sciencedirect.com/science/article/pii/S0191261513000349

@EwoutH
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EwoutH commented Mar 31, 2024

Thanks!

By the way, it might be useful if the Discussions tab could be enabled on this repository. Then users would have a place to discuss questions, configurations and new ideas, without adding noise here in the issues.

It can be enabled very easily, see Enabling GitHub Discussions on your repository.

@EwoutH EwoutH closed this as completed Mar 31, 2024
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