When models are changed from deterministic to stochastic in STEM, how is the probability calculated from the rate values for the parameters that are already entered?
Is it probability= 1- e^(-rate) ?
The reason I am asking is that as some of you know from the last STEM call, I would like to make the disease process (S to I compartment) stochastic, but the recovery process (I to R compartment) deterministic. This is because in my model, there is no recovery unless treatment is used. I use a trigger (with predicate and modifier) to implement treatment at a specific time, at which point the infectious recovery rate is changed from 0 to 1. I want 100% of individuals (or as close as possible) to move from the I to the R compartment at this point, but when I make the model stochastic, this doesn't always happen if I make the infectious recovery rate 1.
If I could know how the probability is calculated from the rate then I might be able to make the value for the recovery rate close to 100% probability, for example by making the recovery rate 10000.
I would appreciate any thoughts or help on this matter.
Emily NixonPhD Student
School of Biological Sciences
University of Bristol
Bristol Life Sciences Building
24 Tyndall Avenue
Tel +44 (0)117 394 1389