Added homophily ratio in basic schelling example

[vbv-shm]

Changed homophily comparing logic as per discussion in #2515.
Now homophily_ratio is checked for agents to be happy. homophily_ratio is similar neighboring agents divided by the total number of neighbors.

[quaquel]

why 0.3? It would make more sense to go to 3/8 (8 is the neighborhood size of a Moore grid with a radius of 1 and all fields occupied.

[vbv-shm]

Thank you for reviewing. I will change 0.3 to 3/8 (0.375).

[vbv-shm]

@quaquel The step size of the slider is 0.1. So the ratio can either be 0.3 or 0.4.
If the ratio is 0.3, agents with 3 similar neighbors and 8 total neighbors will be happy, as 3/8 = 0.375.
And if the ratio is 0.4, agents with 3 similar neighbors and 8 total neighbors won't be happy.
So should I change 0.3 to 0.4?

[EwoutH]

Maybe we can change the step size to 0.125 as well?

[EwoutH]

Thanks for the PR! Could you update your PR description to contain all the necessary information to understand this change on its own? You can use this template if you want.

Edit: I saw there's also this PR open, which also modifies schelling:

• Fix: Schelling Model Neighbor Similarity Calculation #2518

Are there any conflicts between them? I would tend to let #2518 go first, since it was opened earlier. (or did we assign someone to this specific issue?)

[vbv-shm]

@EwoutH Thank you for the reply.
I have understood that #2815 will be given priority because it was opened first. Still, can I work on this PR just in case #2815 doesn't work out? Or is this PR required to be closed?
From now on, I will be careful not to open PR for some issue if PR is already opened.

[quaquel]

I have provided feedback in #2518, if that is not addressed in the coming days and there is no further response, I am fine with merging this instead.

[vbv-shm]

@quaquel Thank you. I understand.

[vbv-shm]

@EwoutH May you please run the benchmark tests?

[vbv-shm]

@quaquel @EwoutH Previously the benchmark tests were failing because I changed homophily to homophily_ratio in the Schelling example. homophily was provided by the configuration file while the model now takes homophily_ratio as input. In order to fix this, I changed homophily to homophily_ratio inside the configuration.
I am curious if my fix is right or not. Could you please run the benchmark tests so that changes can be checked?

[github-actions]

Performance benchmarks:

Model	Size	Init time [95% CI]	Run time [95% CI]
BoltzmannWealth	small	🔵 -2.4% [-3.0%, -1.7%]	🔵 -0.8% [-1.0%, -0.6%]
BoltzmannWealth	large	🔵 -1.3% [-2.5%, -0.1%]	🔵 +0.1% [-0.7%, +0.9%]
Schelling	small	🔵 -1.0% [-1.4%, -0.7%]	🟢 -12.7% [-13.3%, -12.1%]
Schelling	large	🔵 -0.2% [-0.7%, +0.4%]	🔴 +87.2% [+85.6%, +88.6%]
WolfSheep	small	🔵 -2.6% [-3.3%, -1.9%]	🟢 -6.8% [-7.2%, -6.3%]
WolfSheep	large	🟢 -4.8% [-5.5%, -3.9%]	🟢 -8.3% [-9.8%, -6.8%]
BoidFlockers	small	🔵 -1.5% [-2.2%, -0.9%]	🔵 +2.3% [+1.5%, +3.1%]
BoidFlockers	large	🔵 -2.8% [-3.9%, -1.6%]	🔵 +1.4% [+0.7%, +2.2%]

[vbv-shm]

Looks like benchmarks ran, but performance is not up to the mark. So changing homophily to homophily_ratio inside the configuration worked.

[EwoutH]

Thanks for your work. We’re currently waiting on #2518 to be performance validated, one that’s done we can continue with rebasing this PR and checking it’s performance properly.

It’s great it now runs without problem!

[vbv-shm]

Thank you