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SIR model

This is a version of the SIR model for spread of disease and is based on the numberphile video. The x-axis shows units of time. These could be days, weeks, months etc depending on the units that you use for the other values. The y-axis shows:
SusceptibleThe fraction of the population that is able to be infected.
InfectedThe fraction of the population that has the disease and is able to infect others.
RecoveredThe fraction of the population that has been infected and recovered (or died). In this model we assume that you can only get the disease once. This is not the case for COVID19.
There are a number of parameters for you to adjust:
Infection rateThe number of contacts an infected person has per unit time which are sufficient to spread the disease. Not all of these contacts are susceptible.
Recovery rateThe fraction of the infected group that recovers per unit time.
Initial infection rateThe fraction of the population that was infected at the start of the model.
Time to plotThe maximum on the x-axis. Setting this too high can cuase the simulation to lag.
For more detail on how these equations are created, see The Mathematical Association of America.