The EMA is a very handy tool. It lets us calculate an average over recent data. But, unlike a Simple Moving Average, we don't have to keep a window of samples around—we can update an EMA "online," one sample at a time.
But the perennial question is: how do you start an EMA?
First, here are a couple of wrong ways.
Continue reading "The correct way to start an Exponential Moving Average (EMA)"In Fixing dispatch, we refactored some code that dispatched things from a switch-statement or cascading if-statements to dispatching by polymorphism.
This time, we'll refactor a different piece of dispatch in a completely different way, and cover another design principle.
Continue reading "Deciding once"A fun thing about refactoring code is that after one refactor is finished, the next candidate is easier to see.
In An abstraction gone wrong, we refactored the state variable of a simple tokenizer from an integer into an object. Now that that's done, another problem is staring at us in the face. It's in this code:
if (state == INITIAL) { // ... } else if (state == IN_NUMBER) { // ... } else if (state == IN_STRING) { // ... } else if (state == AFTER_STRING) { // ... } else if (state == ESCAPING) { // ... }Continue reading "Fixing dispatch"