Flux.jl/dev/data/onehot/index.html
2019-02-19 15:20:47 +00:00

41 lines
5.3 KiB
HTML
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

<!DOCTYPE html>
<html lang="en"><head><meta charset="UTF-8"/><meta name="viewport" content="width=device-width, initial-scale=1.0"/><title>One-Hot Encoding · Flux</title><script>(function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){
(i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o),
m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m)
})(window,document,'script','https://www.google-analytics.com/analytics.js','ga');
ga('create', 'UA-36890222-9', 'auto');
ga('send', 'pageview');
</script><link href="https://cdnjs.cloudflare.com/ajax/libs/normalize/4.2.0/normalize.min.css" rel="stylesheet" type="text/css"/><link href="https://fonts.googleapis.com/css?family=Lato|Roboto+Mono" rel="stylesheet" type="text/css"/><link href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.6.3/css/font-awesome.min.css" rel="stylesheet" type="text/css"/><link href="https://cdnjs.cloudflare.com/ajax/libs/highlight.js/9.12.0/styles/default.min.css" rel="stylesheet" type="text/css"/><script>documenterBaseURL="../.."</script><script src="https://cdnjs.cloudflare.com/ajax/libs/require.js/2.2.0/require.min.js" data-main="../../assets/documenter.js"></script><script src="../../siteinfo.js"></script><script src="../../../versions.js"></script><link href="../../assets/documenter.css" rel="stylesheet" type="text/css"/><link href="../../assets/flux.css" rel="stylesheet" type="text/css"/></head><body><nav class="toc"><h1>Flux</h1><select id="version-selector" onChange="window.location.href=this.value" style="visibility: hidden"></select><form class="search" id="search-form" action="../../search/"><input id="search-query" name="q" type="text" placeholder="Search docs"/></form><ul><li><a class="toctext" href="../../">Home</a></li><li><span class="toctext">Building Models</span><ul><li><a class="toctext" href="../../models/basics/">Basics</a></li><li><a class="toctext" href="../../models/recurrence/">Recurrence</a></li><li><a class="toctext" href="../../models/regularisation/">Regularisation</a></li><li><a class="toctext" href="../../models/layers/">Model Reference</a></li></ul></li><li><span class="toctext">Training Models</span><ul><li><a class="toctext" href="../../training/optimisers/">Optimisers</a></li><li><a class="toctext" href="../../training/training/">Training</a></li></ul></li><li class="current"><a class="toctext" href>One-Hot Encoding</a><ul class="internal"><li><a class="toctext" href="#Batches-1">Batches</a></li></ul></li><li><a class="toctext" href="../../gpu/">GPU Support</a></li><li><a class="toctext" href="../../saving/">Saving &amp; Loading</a></li><li><a class="toctext" href="../../performance/">Performance Tips</a></li><li><span class="toctext">Internals</span><ul><li><a class="toctext" href="../../internals/tracker/">Backpropagation</a></li></ul></li><li><a class="toctext" href="../../community/">Community</a></li></ul></nav><article id="docs"><header><nav><ul><li><a href>One-Hot Encoding</a></li></ul><a class="edit-page" href="https://github.com/FluxML/Flux.jl/blob/master/docs/src/data/onehot.md"><span class="fa"></span> Edit on GitHub</a></nav><hr/><div id="topbar"><span>One-Hot Encoding</span><a class="fa fa-bars" href="#"></a></div></header><h1><a class="nav-anchor" id="One-Hot-Encoding-1" href="#One-Hot-Encoding-1">One-Hot Encoding</a></h1><p>It&#39;s common to encode categorical variables (like <code>true</code>, <code>false</code> or <code>cat</code>, <code>dog</code>) in &quot;one-of-k&quot; or <a href="https://en.wikipedia.org/wiki/One-hot">&quot;one-hot&quot;</a> form. Flux provides the <code>onehot</code> function to make this easy.</p><pre><code class="language-none">julia&gt; using Flux: onehot, onecold
julia&gt; onehot(:b, [:a, :b, :c])
3-element Flux.OneHotVector:
false
true
false
julia&gt; onehot(:c, [:a, :b, :c])
3-element Flux.OneHotVector:
false
false
true</code></pre><p>The inverse is <code>onecold</code> (which can take a general probability distribution, as well as just booleans).</p><pre><code class="language-julia">julia&gt; onecold(ans, [:a, :b, :c])
:c
julia&gt; onecold([true, false, false], [:a, :b, :c])
:a
julia&gt; onecold([0.3, 0.2, 0.5], [:a, :b, :c])
:c</code></pre><h2><a class="nav-anchor" id="Batches-1" href="#Batches-1">Batches</a></h2><p><code>onehotbatch</code> creates a batch (matrix) of one-hot vectors, and <code>onecold</code> treats matrices as batches.</p><pre><code class="language-julia">julia&gt; using Flux: onehotbatch
julia&gt; onehotbatch([:b, :a, :b], [:a, :b, :c])
3×3 Flux.OneHotMatrix:
false true false
true false true
false false false
julia&gt; onecold(ans, [:a, :b, :c])
3-element Array{Symbol,1}:
:b
:a
:b</code></pre><p>Note that these operations returned <code>OneHotVector</code> and <code>OneHotMatrix</code> rather than <code>Array</code>s. <code>OneHotVector</code>s behave like normal vectors but avoid any unnecessary cost compared to using an integer index directly. For example, multiplying a matrix with a one-hot vector simply slices out the relevant row of the matrix under the hood.</p><footer><hr/><a class="previous" href="../../training/training/"><span class="direction">Previous</span><span class="title">Training</span></a><a class="next" href="../../gpu/"><span class="direction">Next</span><span class="title">GPU Support</span></a></footer></article></body></html>