How to deal with underflow in scientific computing?

Question

I am working on probabilistic models, and when doing inference on those models, the estimated probabilities can become very small. In order to avoid underflow, I am currently wo

Answer 1

I don't understand why this works, but this formula seems to work and is simpler:

c = a + log(1 + exp(b - a))

Where c = log(exp(a)+exp(b))