DefMemo

A memoization macro (defmemo) for Elixir.

Build Status

Adapted from : (Gustavo Brunoro) https://gist.github.com/brunoro/6159378

I found Gustavo's Gist when looking at memoization and elixir and fixed it to work with version 1.0.x. Since then I've fixed a few of the problems with the original implementation:

Usage

Add defmemo to your mix.exs file:

{:defmemo, "~> 0.1.0"}

And run:

mix deps.get

Before using a defmemo'd function start_link must be called. e.g.

DefMemo.start_link

or you can add :defmemo into the applications section of your mix.exs:

[applications: [:logger, :defmemo]]

Example

defmodule FibMemo do

  import DefMemo

     

  defmemo fibs(0), do: 0

  defmemo fibs(1), do: 1

  defmemo fibs(n), do: fibs(n - 1) + fibs(n - 2)



  def fib_10 do

    fibs(10)

  end

end

Performance

More or less what you would expect:

UNMEMOIZED VS MEMOIZED 

***********************

fib (unmemoized)

function -> {result, running time(μs)}

==================================

fibs(30) -> {832040, 31364}

fibs(30) -> {832040, 31281}



FibMemo (memoized)

==================================

fibs(30) -> {832040, 975}

fibs(30) -> {832040, 8}

fibs(50) -> {12586269025, 176}

fibs(50) -> {12586269025, 7}

TODO