activation.html



<!DOCTYPE html>
<!--[if IE 8]><html class="no-js lt-ie9" lang="en" > <![endif]-->
<!--[if gt IE 8]><!--> <html class="no-js" lang="en" > <!--<![endif]-->
<head>
  <meta charset="utf-8">
  
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  
  <title>Activation &mdash; PaddlePaddle  documentation</title>
  

    <link rel="stylesheet" href="../../_static/css/theme.css" type="text/css" />
  

        <link rel="index" title="Index"
              href="../../genindex.html"/>
        <link rel="search" title="Search" href="../../search.html"/>
    <link rel="top" title="PaddlePaddle  documentation" href="../../index.html"/>
        <link rel="up" title="Model Configuration" href="../model_configs.html"/>
        <link rel="next" title="Layers" href="layer.html"/>
        <link rel="prev" title="Model Configuration" href="../model_configs.html"/> 

  <link rel="stylesheet" href="https://cdn.jsdelivr.net/perfect-scrollbar/0.6.14/css/perfect-scrollbar.min.css" type="text/css" />
  <link rel="stylesheet" href="../../_static/css/override.css" type="text/css" />
  <script>
  var _hmt = _hmt || [];
  (function() {
    var hm = document.createElement("script");
    hm.src = "//hm.baidu.com/hm.js?b9a314ab40d04d805655aab1deee08ba";
    var s = document.getElementsByTagName("script")[0]; 
    s.parentNode.insertBefore(hm, s);
  })();
  </script>

  
  <script src="../../_static/js/modernizr.min.js"></script>

</head>

<body class="wy-body-for-nav" role="document">

  
  <header class="site-header">
    <div class="site-logo">
      <a href="/"><img src="../../_static/images/PP_w.png"></a>
    </div>
    <div class="site-nav-links">
      <div class="site-menu">
        <a class="fork-on-github" href="https://github.com/PaddlePaddle/Paddle" target="_blank"><i class="fa fa-github"></i>Fork me on Github</a>
        <div class="language-switcher dropdown">
          <a type="button" data-toggle="dropdown">
            <span>English</span>
            <i class="fa fa-angle-up"></i>
            <i class="fa fa-angle-down"></i>
          </a>
          <ul class="dropdown-menu">
            <li><a href="/doc_cn">中文</a></li>
            <li><a href="/doc">English</a></li>
          </ul>
        </div>
        <ul class="site-page-links">
          <li><a href="/">Home</a></li>
        </ul>
      </div>
      <div class="doc-module">
        
        <ul class="current">
<li class="toctree-l1"><a class="reference internal" href="../../overview.html">V2 API Overview</a></li>
<li class="toctree-l1 current"><a class="reference internal" href="../model_configs.html">Model Configuration</a></li>
<li class="toctree-l1"><a class="reference internal" href="../data.html">Data Reader Interface and DataSets</a></li>
<li class="toctree-l1"><a class="reference internal" href="../run_logic.html">Training and Inference</a></li>
<li class="toctree-l1"><a class="reference internal" href="../../fluid/index.html">Fluid</a></li>
</ul>

        
<div role="search">
  <form id="rtd-search-form" class="wy-form" action="../../search.html" method="get">
    <input type="text" name="q" placeholder="Search docs" />
    <input type="hidden" name="check_keywords" value="yes" />
    <input type="hidden" name="area" value="default" />
  </form>
</div>        
      </div>
    </div>
  </header>
  
  <div class="main-content-wrap">

    
    <nav class="doc-menu-vertical" role="navigation">
        
          
          <ul class="current">
<li class="toctree-l1"><a class="reference internal" href="../../overview.html">V2 API Overview</a></li>
<li class="toctree-l1 current"><a class="reference internal" href="../model_configs.html">Model Configuration</a><ul class="current">
<li class="toctree-l2 current"><a class="current reference internal" href="#">Activation</a></li>
<li class="toctree-l2"><a class="reference internal" href="layer.html">Layers</a></li>
<li class="toctree-l2"><a class="reference internal" href="evaluators.html">Evaluators</a></li>
<li class="toctree-l2"><a class="reference internal" href="optimizer.html">Optimizer</a></li>
<li class="toctree-l2"><a class="reference internal" href="pooling.html">Pooling</a></li>
<li class="toctree-l2"><a class="reference internal" href="networks.html">Networks</a></li>
<li class="toctree-l2"><a class="reference internal" href="attr.html">Parameter Attribute</a></li>
</ul>
</li>
<li class="toctree-l1"><a class="reference internal" href="../data.html">Data Reader Interface and DataSets</a><ul>
<li class="toctree-l2"><a class="reference internal" href="../data/data_reader.html">Data Reader Interface</a></li>
<li class="toctree-l2"><a class="reference internal" href="../data/image.html">Image Interface</a></li>
<li class="toctree-l2"><a class="reference internal" href="../data/dataset.html">Dataset</a></li>
</ul>
</li>
<li class="toctree-l1"><a class="reference internal" href="../run_logic.html">Training and Inference</a></li>
<li class="toctree-l1"><a class="reference internal" href="../../fluid/index.html">Fluid</a><ul>
<li class="toctree-l2"><a class="reference internal" href="../../fluid/layers.html">layers</a></li>
<li class="toctree-l2"><a class="reference internal" href="../../fluid/data_feeder.html">data_feeder</a></li>
<li class="toctree-l2"><a class="reference internal" href="../../fluid/executor.html">executor</a></li>
<li class="toctree-l2"><a class="reference internal" href="../../fluid/initializer.html">initializer</a></li>
<li class="toctree-l2"><a class="reference internal" href="../../fluid/evaluator.html">evaluator</a></li>
<li class="toctree-l2"><a class="reference internal" href="../../fluid/nets.html">nets</a></li>
<li class="toctree-l2"><a class="reference internal" href="../../fluid/optimizer.html">optimizer</a></li>
<li class="toctree-l2"><a class="reference internal" href="../../fluid/param_attr.html">param_attr</a></li>
<li class="toctree-l2"><a class="reference internal" href="../../fluid/profiler.html">profiler</a></li>
<li class="toctree-l2"><a class="reference internal" href="../../fluid/regularizer.html">regularizer</a></li>
<li class="toctree-l2"><a class="reference internal" href="../../fluid/io.html">io</a></li>
</ul>
</li>
</ul>

        
    </nav>
    
    <section class="doc-content-wrap">

      
<div role="navigation" aria-label="breadcrumbs navigation">
  <ul class="wy-breadcrumbs">
      
        <li><a href="../model_configs.html">Model Configuration</a> > </li>
      
    <li>Activation</li>
  </ul>
</div>
      
      <div class="wy-nav-content" id="doc-content">
        <div class="rst-content">
          <div role="main" class="document" itemscope="itemscope" itemtype="http://schema.org/Article">
           <div itemprop="articleBody">
            
  <div class="section" id="activation">
<h1>Activation<a class="headerlink" href="#activation" title="Permalink to this headline">¶</a></h1>
<div class="section" id="abs">
<h2>Abs<a class="headerlink" href="#abs" title="Permalink to this headline">¶</a></h2>
<dl class="class">
<dt>
<em class="property">class </em><code class="descclassname">paddle.v2.activation.</code><code class="descname">Abs</code></dt>
<dd><p>Abs Activation.</p>
<p>Forward:    <span class="math">\(f(z) = abs(z)\)</span></p>
<p>Derivative:</p>
<div class="math">
\[\begin{split}1 &amp;\quad if \quad z &gt; 0 \\
-1 &amp;\quad if \quad z &lt; 0 \\
0 &amp;\quad if \quad z = 0\end{split}\]</div>
</dd></dl>

</div>
<div class="section" id="exp">
<h2>Exp<a class="headerlink" href="#exp" title="Permalink to this headline">¶</a></h2>
<dl class="class">
<dt>
<em class="property">class </em><code class="descclassname">paddle.v2.activation.</code><code class="descname">Exp</code></dt>
<dd><p>Exponential Activation.</p>
<div class="math">
\[f(z) = e^z.\]</div>
</dd></dl>

</div>
<div class="section" id="identity">
<h2>Identity<a class="headerlink" href="#identity" title="Permalink to this headline">¶</a></h2>
<dl class="attribute">
<dt>
<code class="descclassname">paddle.v2.activation.</code><code class="descname">Identity</code></dt>
<dd><p>alias of <code class="xref py py-class docutils literal"><span class="pre">Linear</span></code></p>
</dd></dl>

</div>
<div class="section" id="linear">
<h2>Linear<a class="headerlink" href="#linear" title="Permalink to this headline">¶</a></h2>
<dl class="class">
<dt>
<em class="property">class </em><code class="descclassname">paddle.v2.activation.</code><code class="descname">Linear</code></dt>
<dd><p>Identity Activation.</p>
<p>Just do nothing for output both forward/backward.</p>
</dd></dl>

</div>
<div class="section" id="log">
<h2>Log<a class="headerlink" href="#log" title="Permalink to this headline">¶</a></h2>
<dl class="class">
<dt>
<em class="property">class </em><code class="descclassname">paddle.v2.activation.</code><code class="descname">Log</code></dt>
<dd><p>Logarithm Activation.</p>
<div class="math">
\[f(z) = log(z)\]</div>
</dd></dl>

</div>
<div class="section" id="square">
<h2>Square<a class="headerlink" href="#square" title="Permalink to this headline">¶</a></h2>
<dl class="class">
<dt>
<em class="property">class </em><code class="descclassname">paddle.v2.activation.</code><code class="descname">Square</code></dt>
<dd><p>Square Activation.</p>
<div class="math">
\[f(z) = z^2.\]</div>
</dd></dl>

</div>
<div class="section" id="sigmoid">
<h2>Sigmoid<a class="headerlink" href="#sigmoid" title="Permalink to this headline">¶</a></h2>
<dl class="class">
<dt>
<em class="property">class </em><code class="descclassname">paddle.v2.activation.</code><code class="descname">Sigmoid</code></dt>
<dd><p>Sigmoid activation.</p>
<div class="math">
\[f(z) = \frac{1}{1+exp(-z)}\]</div>
</dd></dl>

</div>
<div class="section" id="softmax">
<h2>Softmax<a class="headerlink" href="#softmax" title="Permalink to this headline">¶</a></h2>
<dl class="class">
<dt>
<em class="property">class </em><code class="descclassname">paddle.v2.activation.</code><code class="descname">Softmax</code></dt>
<dd><p>Softmax activation for simple input</p>
<div class="math">
\[P(y=j|x) = \frac{e^{x_j}} {\sum^K_{k=1} e^{x_j} }\]</div>
</dd></dl>

</div>
<div class="section" id="sequencesoftmax">
<h2>SequenceSoftmax<a class="headerlink" href="#sequencesoftmax" title="Permalink to this headline">¶</a></h2>
<dl class="class">
<dt>
<em class="property">class </em><code class="descclassname">paddle.v2.activation.</code><code class="descname">SequenceSoftmax</code></dt>
<dd><p>Softmax activation for one sequence. The dimension of input feature must be
1 and a sequence.</p>
<div class="code python highlight-default"><div class="highlight"><pre><span></span><span class="n">result</span> <span class="o">=</span> <span class="n">softmax</span><span class="p">(</span><span class="k">for</span> <span class="n">each_feature_vector</span><span class="p">[</span><span class="mi">0</span><span class="p">]</span> <span class="ow">in</span> <span class="n">input_feature</span><span class="p">)</span>
<span class="k">for</span> <span class="n">i</span><span class="p">,</span> <span class="n">each_time_step_output</span> <span class="ow">in</span> <span class="nb">enumerate</span><span class="p">(</span><span class="n">output</span><span class="p">):</span>
    <span class="n">each_time_step_output</span> <span class="o">=</span> <span class="n">result</span><span class="p">[</span><span class="n">i</span><span class="p">]</span>
</pre></div>
</div>
</dd></dl>

</div>
<div class="section" id="relu">
<h2>Relu<a class="headerlink" href="#relu" title="Permalink to this headline">¶</a></h2>
<dl class="class">
<dt>
<em class="property">class </em><code class="descclassname">paddle.v2.activation.</code><code class="descname">Relu</code></dt>
<dd><p>Relu activation.</p>
<p>forward. <span class="math">\(y = max(0, z)\)</span></p>
<p>derivative:</p>
<div class="math">
\[\begin{split}1  &amp;\quad if z &gt; 0 \\
0  &amp;\quad\mathrm{otherwize}\end{split}\]</div>
</dd></dl>

</div>
<div class="section" id="brelu">
<h2>BRelu<a class="headerlink" href="#brelu" title="Permalink to this headline">¶</a></h2>
<dl class="class">
<dt>
<em class="property">class </em><code class="descclassname">paddle.v2.activation.</code><code class="descname">BRelu</code></dt>
<dd><p>BRelu Activation.</p>
<p>forward.  <span class="math">\(y = min(24, max(0, z))\)</span></p>
<p>derivative:</p>
<div class="math">
\[\begin{split}1  &amp;\quad if 0 &lt; z &lt; 24 \\
0  &amp;\quad \mathrm{otherwise}\end{split}\]</div>
</dd></dl>

</div>
<div class="section" id="softrelu">
<h2>SoftRelu<a class="headerlink" href="#softrelu" title="Permalink to this headline">¶</a></h2>
<dl class="class">
<dt>
<em class="property">class </em><code class="descclassname">paddle.v2.activation.</code><code class="descname">SoftRelu</code></dt>
<dd><p>SoftRelu Activation.</p>
</dd></dl>

</div>
<div class="section" id="tanh">
<h2>Tanh<a class="headerlink" href="#tanh" title="Permalink to this headline">¶</a></h2>
<dl class="class">
<dt>
<em class="property">class </em><code class="descclassname">paddle.v2.activation.</code><code class="descname">Tanh</code></dt>
<dd><p>Tanh activation.</p>
<div class="math">
\[f(z)=tanh(z)=\frac{e^z-e^{-z}}{e^z+e^{-z}}\]</div>
</dd></dl>

</div>
<div class="section" id="stanh">
<h2>STanh<a class="headerlink" href="#stanh" title="Permalink to this headline">¶</a></h2>
<dl class="class">
<dt>
<em class="property">class </em><code class="descclassname">paddle.v2.activation.</code><code class="descname">STanh</code></dt>
<dd><p>Scaled Tanh Activation.</p>
<div class="math">
\[f(z) = 1.7159 * tanh(2/3*z)\]</div>
</dd></dl>

</div>
<div class="section" id="softsign">
<h2>SoftSign<a class="headerlink" href="#softsign" title="Permalink to this headline">¶</a></h2>
<dl class="class">
<dt>
<em class="property">class </em><code class="descclassname">paddle.v2.activation.</code><code class="descname">SoftSign</code></dt>
<dd><p>SoftSign Activation.</p>
<div class="math">
\[f(z)=\frac{z}{1 + |z|}\]</div>
</dd></dl>

</div>
</div>


           </div>
          </div>
          <footer>
  
    <div class="rst-footer-buttons" role="navigation" aria-label="footer navigation">
      
        <a href="layer.html" class="btn btn-neutral float-right" title="Layers" accesskey="n">Next <span class="fa fa-arrow-circle-right"></span></a>
      
      
        <a href="../model_configs.html" class="btn btn-neutral" title="Model Configuration" accesskey="p"><span class="fa fa-arrow-circle-left"></span> Previous</a>
      
    </div>
  

  <hr/>

  <div role="contentinfo">
    <p>
        &copy; Copyright 2016, PaddlePaddle developers.

    </p>
  </div>
  Built with <a href="http://sphinx-doc.org/">Sphinx</a> using a <a href="https://github.com/snide/sphinx_rtd_theme">theme</a> provided by <a href="https://readthedocs.org">Read the Docs</a>. 

</footer>

        </div>
      </div>

    </section>

  </div>
  

    <script type="text/javascript">
        var DOCUMENTATION_OPTIONS = {
            URL_ROOT:'../../',
            VERSION:'',
            COLLAPSE_INDEX:false,
            FILE_SUFFIX:'.html',
            HAS_SOURCE:  true,
            SOURCELINK_SUFFIX: ".txt",
        };
    </script>
      <script type="text/javascript" src="../../_static/jquery.js"></script>
      <script type="text/javascript" src="../../_static/underscore.js"></script>
      <script type="text/javascript" src="../../_static/doctools.js"></script>
      <script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.0/MathJax.js?config=TeX-AMS-MML_HTMLorMML"></script>
       
  
    <script type="text/javascript" src="../../_static/js/theme.js"></script>
  
  
  <script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js" integrity="sha384-Tc5IQib027qvyjSMfHjOMaLkfuWVxZxUPnCJA7l2mCWNIpG9mGCD8wGNIcPD7Txa" crossorigin="anonymous"></script>
  <script src="https://cdn.jsdelivr.net/perfect-scrollbar/0.6.14/js/perfect-scrollbar.jquery.min.js"></script>
  <script src="../../_static/js/paddle_doc_init.js"></script> 

</body>
</html>