Flux.jl/previews/PR1150/models/losses/index.html

12 lines
18 KiB
HTML
Raw Normal View History

2020-04-29 10:54:42 +00:00
<!DOCTYPE html>
<html lang="en"><head><meta charset="UTF-8"/><meta name="viewport" content="width=device-width, initial-scale=1.0"/><title>Loss Functions · 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', {'page': location.pathname + location.search + location.hash});
</script><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/5.11.2/css/fontawesome.min.css" rel="stylesheet" type="text/css"/><link href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/5.11.2/css/solid.min.css" rel="stylesheet" type="text/css"/><link href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/5.11.2/css/brands.min.css" rel="stylesheet" type="text/css"/><link href="https://cdnjs.cloudflare.com/ajax/libs/KaTeX/0.11.1/katex.min.css" rel="stylesheet" type="text/css"/><script>documenterBaseURL="../.."</script><script src="https://cdnjs.cloudflare.com/ajax/libs/require.js/2.3.6/require.min.js" data-main="../../assets/documenter.js"></script><script src="../../siteinfo.js"></script><script src="../../../versions.js"></script><link href="../../assets/flux.css" rel="stylesheet" type="text/css"/><link class="docs-theme-link" rel="stylesheet" type="text/css" href="../../assets/themes/documenter-dark.css" data-theme-name="documenter-dark"/><link class="docs-theme-link" rel="stylesheet" type="text/css" href="../../assets/themes/documenter-light.css" data-theme-name="documenter-light" data-theme-primary/><script src="../../assets/themeswap.js"></script></head><body><div id="documenter"><nav class="docs-sidebar"><div class="docs-package-name"><span class="docs-autofit">Flux</span></div><form class="docs-search" action="../../search/"><input class="docs-search-query" id="documenter-search-query" name="q" type="text" placeholder="Search docs"/></form><ul class="docs-menu"><li><a class="tocitem" href="../../">Home</a></li><li><span class="tocitem">Building Models</span><ul><li><a class="tocitem" href="../basics/">Basics</a></li><li><a class="tocitem" href="../recurrence/">Recurrence</a></li><li><a class="tocitem" href="../layers/">Model Reference</a></li><li class="is-active"><a class="tocitem" href>Loss Functions</a><ul class="internal"><li><a class="tocitem" href="#Loss-Functions-1"><span>Loss Functions</span></a></li></ul></li><li><a class="tocitem" href="../regularisation/">Regularisation</a></li><li><a class="tocitem" href="../advanced/">Advanced Model Building</a></li><li><a class="tocitem" href="../nnlib/">NNlib</a></li></ul></li><li><span class="tocitem">Handling Data</span><ul><li><a class="tocitem" href="../../data/onehot/">One-Hot Encoding</a></li><li><a class="tocitem" href="../../data/dataloader/">DataLoader</a></li></ul></li><li><span class="tocitem">Training Models</span><ul><li><a class="tocitem" href="../../training/optimisers/">Optimisers</a></li><li><a class="tocitem" href="../../training/training/">Training</a></li></ul></li><li><a class="tocitem" href="../../gpu/">GPU Support</a></li><li><a class="tocitem" href="../../saving/">Saving &amp; Loading</a></li><li><a class="tocitem" href="../../ecosystem/">The Julia Ecosystem</a></li><li><a class="tocitem" href="../../utilities/">Utility Functions</a></li><li><a class="tocitem" href="../../performance/">Performance Tips</a></li><li><a class="tocitem" href="../../datasets/">Datasets</a></li><li><a class="tocitem" href="../../community/">Community</a></li></ul><div class="docs-version-selector field has-addons"><div class="control"><span class="docs-label button is-static is-size-7">Version</span></div><div class="docs-selector control is-expanded"><div class="select is-fullwidth is-size-7"><select id="documenter-version-selector"></select></div></div></div></nav><div class="docs-main"><header class="docs-navbar"><nav class="breadcrumb"><ul class="is-hidden-mobile"><li><a class="is-disabled">Building Models</a></li><li class="is-active"><a href>Loss Functions</a></li></ul><ul class="is-hidden-tablet"><li class="is-active"><a href>Loss Functions</a></li></ul></nav><div class="docs-right"><a class="docs-edit-link" href="https://github.com/FluxML/Flux.jl/blob/master/docs/src/models/losses.md" title="Edit on GitHub"><span class="docs-icon fab"></span><span class="docs-label is-hidden-touch">Edit on GitHub</span></a><a class="docs-settings-b
Huber loss = |
| δ * (|ŷ - y| - 0.5 * δ), otherwise</code></pre></div><a class="docs-sourcelink" target="_blank" href="https://github.com/FluxML/Flux.jl/blob/bf9fe18c47e89df1f0f09df06be3b7f2c7925a3e/src/layers/losses.jl#L33-L42">source</a></section></article><article class="docstring"><header><a class="docstring-binding" id="Flux.crossentropy" href="#Flux.crossentropy"><code>Flux.crossentropy</code></a><span class="docstring-category">Function</span></header><section><div><pre><code class="language-julia">crossentropy(ŷ, y; weight=nothing, dims=1, ϵ=eps(eltype(ŷ)), agg=mean)</code></pre><p>Return the cross entropy between the given probability distributions; calculated as</p><pre><code class="language-none">agg(.-sum(weight .* y .* log.(ŷ .+ ϵ); dims=dims))agg=mean,</code></pre><p><code>weight</code> can be <code>nothing</code>, a number or an array. <code>weight=nothing</code> acts like <code>weight=1</code> but is faster.</p><p>See also: <a href="#Flux.logitcrossentropy"><code>Flux.logitcrossentropy</code></a>, <a href="#Flux.binarycrossentropy"><code>Flux.binarycrossentropy</code></a>, <a href="#Flux.logitbinarycrossentropy"><code>Flux.logitbinarycrossentropy</code></a></p></div><a class="docs-sourcelink" target="_blank" href="https://github.com/FluxML/Flux.jl/blob/bf9fe18c47e89df1f0f09df06be3b7f2c7925a3e/src/layers/losses.jl#L54-L66">source</a></section></article><article class="docstring"><header><a class="docstring-binding" id="Flux.logitcrossentropy" href="#Flux.logitcrossentropy"><code>Flux.logitcrossentropy</code></a><span class="docstring-category">Function</span></header><section><div><pre><code class="language-julia">logitcrossentropy(ŷ, y; weight=nothing, agg=mean, dims=1)</code></pre><p>Return the crossentropy computed after a <a href="../nnlib/#NNlib.logsoftmax"><code>Flux.logsoftmax</code></a> operation; calculated as</p><pre><code class="language-none">agg(.-sum(weight .* y .* logsoftmax(ŷ; dims=dims); dims=dims))</code></pre><p><code>logitcrossentropy(ŷ, y)</code> is mathematically equivalent to <a href="#Flux.crossentropy"><code>Flux.crossentropy(softmax(log.(ŷ)), y)</code></a> but it is more numerically stable.</p><p>See also: <a href="#Flux.crossentropy"><code>Flux.crossentropy</code></a>, <a href="#Flux.binarycrossentropy"><code>Flux.binarycrossentropy</code></a>, <a href="#Flux.logitbinarycrossentropy"><code>Flux.logitbinarycrossentropy</code></a></p></div><a class="docs-sourcelink" target="_blank" href="https://github.com/FluxML/Flux.jl/blob/bf9fe18c47e89df1f0f09df06be3b7f2c7925a3e/src/layers/losses.jl#L71-L83">source</a></section></article><article class="docstring"><header><a class="docstring-binding" id="Flux.binarycrossentropy" href="#Flux.binarycrossentropy"><code>Flux.binarycrossentropy</code></a><span class="docstring-category">Function</span></header><section><div><pre><code class="language-julia">binarycrossentropy(ŷ, y; ϵ=eps(ŷ))</code></pre><p>Return <span>$-y*\log(ŷ + ϵ) - (1-y)*\log(1-ŷ + ϵ)$</span>. The <code>ϵ</code> term provides numerical stability.</p><p>Typically, the prediction <code></code> is given by the output of a <a href="../nnlib/#NNlib.sigmoid"><code>sigmoid</code></a> activation.</p><p>See also: <a href="#Flux.crossentropy"><code>Flux.crossentropy</code></a>, <a href="#Flux.logitcrossentropy"><code>Flux.logitcrossentropy</code></a>, <a href="#Flux.logitbinarycrossentropy"><code>Flux.logitbinarycrossentropy</code></a></p></div><a class="docs-sourcelink" target="_blank" href="https://github.com/FluxML/Flux.jl/blob/bf9fe18c47e89df1f0f09df06be3b7f2c7925a3e/src/layers/losses.jl#L88-L96">source</a></section></article><article class="docstring"><header><a class="docstring-binding" id="Flux.logitbinarycrossentropy" href="#Flux.logitbinarycrossentropy"><code>Flux.logitbinarycrossentropy</code></a><span class="docstring-category">Function</span></header><section><div><pre><code class="language-julia">logitbinarycrossentropy(ŷ, y; agg=mean)</code></pre><p><code>logitbinarycrossentropy(ŷ, y)</code> is mathematically equivale