Motivationn & Definition

In this post, we explain the concept of Log-Sum-Exp .

Suppose we have three extremely small numbers: $a_1 = e^{-200}, a_2 = e^{-201}, a_3 = e^{-202}$. We are interested in the log of their sum.

There are two issues to solve here:

  1. The sum will still be very small. To make the result more readible, we want to take the logarithm of it.
  2. Dealing with extremely small numbers may lead to <a …