Hands-On Design Patterns and Best Practices with Julia

Improving the performance of the Fibonacci function

First, let's analyze how bad the performance is by revising the function to keep track of the number of executions. The code is as follows:

function fib(n)    if n < 3        return (result = 1, counter = 1)    else        result1, counter1 = fib(n - 1)        result2, counter2 = fib(n - 2)        return (result = result1 + result2, counter = 1 + counter1 + counter2)    endend

Every time the fib function is called, it keeps tracks a counter. If the value of n is smaller than 3, then it returns the count of 1 along with the result. If n is a larger number, then it aggregates the counts from the recursive calls to fib function.

Let's run it several times with various input values:

This simple example just illustrated how quickly ...