## How to write a decay function in Python

At my exercise of reinforcement learning, I needed to write a decay function for Ɛ-greedy strategy. The mathematical function should look something like:

`f(x) = decay^x`

But in the algorithm, I don't have access to the iterator value (x in the above formula), only the current epsilon (Ɛ) and the decay factor I defined.

It turns out it is not necessary to use x to obtain the same value. If `x`

is the current step in the iteration, all that is needed to do is:

`Ɛ = Ɛ * decay`

It would translate to

`Ɛ = Ɛ * decay ^ X`

Where `X`

would be the total amount of steps in the iteration. In python, the code would look like:

`self.epsilon = self.epsilon * self.decay`

Although simple, it took me some time to visualize both functions are equal but written in different forms.

**Tags: **decay, epsilon-greedy, programming, python, reinforcement learning