File talk:Sirsys-p9.png

Latest comment: 4 years ago by GregoryKaiser

I believe the code should read:

beta=0.001 v=0.1

(as it was in the original description of the graph)

Otherwise the 'infection' happens much more quickly.

However, I've never done this stuff before so am appealling for someone to check it.

The code omits the population size N, so it has to bake it into the beta constant. Looking at the original parameters beta=0.005, v=0.05 if you take the 500 out of beta then N=500, β=2.5, and γ=0.05; now find R_0 = β/γ = 2.5/0.05 = 50, compared to the population parameters N/S(0) = 500/499 = 1.002 which should take over very early on at about 50:1. So likewise looking at your numbers beta=0.001 and v=0.1 the takeover is much later on about 5:1, and the typo is likely in that v should probably be v=0.5 instead of 0.05 so they cross at about the same time; however I do like your N=500, β=0.5, γ=0.1 more because IMO they flatten out the curves nicely GregoryKaiser (talk) 16:18, 1 April 2020 (UTC)Reply