https://github.com/os6sense/DefMemo

DefMemo - Ryuk's little puppy! Bring apples.
https://github.com/os6sense/DefMemo

Last synced: 3 months ago
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DefMemo - Ryuk's little puppy! Bring apples.

• Host: GitHub
• URL: https://github.com/os6sense/DefMemo
• Owner: os6sense
• License: mit
• Created: 2015-03-09T10:19:09.000Z (almost 10 years ago)
• Default Branch: master
• Last Pushed: 2017-03-12T13:41:12.000Z (almost 8 years ago)
• Last Synced: 2024-10-08T12:12:39.516Z (4 months ago)
• Language: Elixir
• Homepage:
• Size: 28.3 KB
• Stars: 33
• Watchers: 4
• Forks: 5
• Open Issues: 2
• Metadata Files:
  • Readme: README.md
  • License: LICENSE.txt

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README

        
DefMemo

=======

A memoization macro (defmemo) for Elixir.

[![Build Status](https://travis-ci.org/os6sense/DefMemo.svg?branch=master)](https://travis-ci.org/os6sense/DefMemo)

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:

- will correctly memoize the results of functions with identical signatures

  but in different modules.

- will work with 'when' guard clauses in function definitions. (That was fun!)

- Added lots of lovely tests.

Usage

=====

Add defmemo to your mix.exs file:

    {:defmemo, "~> 0.1.0"}

And run:

    mix deps.get

Before *using* a defmemo'd function (it's fine to define them), 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

===========

As you would expect for something like fibs, memoization provides dramatic

performance improvements:

    UNMEMOIZED VS MEMOIZED

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

    fib (unmemoized)

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

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

    fibs(30) -> {832040, 31089}

    fibs(30) -> {832040, 31833}

    FibMemo (memoized)

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

    fibs(30) -> {832040, 79}

    fibs(30) -> {832040, 3}

    fibs(50) -> {12586269025, 103}

    fibs(50) -> {12586269025, 3}

Note that these have also improved from version 0.1 to 0.1.1. The above numbers

are on the low end of the spectrum with access ranging from 2 to 15 μs for me.

TODO

====

- Add test for supervisor crashing.

- Look at injecting the type of result table used.

- Better documentation.

- More tests (alwaaaays with the testing!)

- Test with some biger data (e.g. for something like web crawling)

- ~~Supervisor ~~

- ~~Redis Based ResultTable - I've been playing with this - obviously there are

  limitations on type and it's slower than gen server but there are of course

  circumstances where it could be useful but for the most part its not a good

  "fit".~~