Skip to main content

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [List Home]
[stem-dev] Rate to probability, deterministic to stochastic

Hi all,

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.

Best wishes,


Emily Nixon
PhD Student

School of Biological Sciences

University of Bristol
Bristol Life Sciences Building
24 Tyndall Avenue

Tel +44 (0)117 394 1389

Back to the top