Programming Elixir 1.2

A Fibonacci Server

Let’s round out this chapter with an example program. Its task is to calculate fib(n) for a list of n, where fib(n) is the n^th Fibonacci number. (The Fibonacci sequence starts 0, 1. Each subsequent number is the sum of the preceding two numbers in the sequence.)^[28] I chose this not because it is something we all do every day, but because the naïve calculation of Fibonacci numbers 10 through 37 takes a measurable number of seconds on typical computers.

The twist is that we’ll write our program to calculate different Fibonacci numbers in parallel. To do this, we’ll write a trivial server process that does the calculation, and a scheduler that assigns work to a calculation process when it becomes free. The following diagram ...