activations.html



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<li><a class="reference internal" href="#">Activations</a><ul>
<li><a class="reference internal" href="#baseactivation">BaseActivation</a></li>
<li><a class="reference internal" href="#absactivation">AbsActivation</a></li>
<li><a class="reference internal" href="#expactivation">ExpActivation</a></li>
<li><a class="reference internal" href="#identityactivation">IdentityActivation</a></li>
<li><a class="reference internal" href="#linearactivation">LinearActivation</a></li>
<li><a class="reference internal" href="#logactivation">LogActivation</a></li>
<li><a class="reference internal" href="#squareactivation">SquareActivation</a></li>
<li><a class="reference internal" href="#sigmoidactivation">SigmoidActivation</a></li>
<li><a class="reference internal" href="#softmaxactivation">SoftmaxActivation</a></li>
<li><a class="reference internal" href="#sequencesoftmaxactivation">SequenceSoftmaxActivation</a></li>
<li><a class="reference internal" href="#reluactivation">ReluActivation</a></li>
<li><a class="reference internal" href="#breluactivation">BReluActivation</a></li>
<li><a class="reference internal" href="#softreluactivation">SoftReluActivation</a></li>
<li><a class="reference internal" href="#tanhactivation">TanhActivation</a></li>
<li><a class="reference internal" href="#stanhactivation">STanhActivation</a></li>
</ul>
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  <div class="section" id="activations">
<h1>Activations<a class="headerlink" href="#activations" title="永久链接至标题">¶</a></h1>
<div class="section" id="baseactivation">
<h2>BaseActivation<a class="headerlink" href="#baseactivation" title="永久链接至标题">¶</a></h2>
<dl class="class">
<dt>
<em class="property">class </em><code class="descclassname">paddle.trainer_config_helpers.activations.</code><code class="descname">BaseActivation</code><span class="sig-paren">(</span><em>name</em>, <em>support_hppl</em><span class="sig-paren">)</span></dt>
<dd><p>A mark for activation class.
Each activation inherit BaseActivation, which has two parameters.</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field-odd field"><th class="field-name">参数:</th><td class="field-body"><ul class="first last simple">
<li><strong>name</strong> (<em>basestring</em>) &#8211; activation name in paddle config.</li>
<li><strong>support_hppl</strong> (<em>bool</em>) &#8211; True if supported by hppl. HPPL is a library used by paddle
internally. Currently, lstm layer can only use activations
supported by hppl.</li>
</ul>
</td>
</tr>
</tbody>
</table>
</dd></dl>

</div>
<div class="section" id="absactivation">
<h2>AbsActivation<a class="headerlink" href="#absactivation" title="永久链接至标题">¶</a></h2>
<dl class="class">
<dt>
<em class="property">class </em><code class="descclassname">paddle.trainer_config_helpers.activations.</code><code class="descname">AbsActivation</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="expactivation">
<h2>ExpActivation<a class="headerlink" href="#expactivation" title="永久链接至标题">¶</a></h2>
<dl class="class">
<dt>
<em class="property">class </em><code class="descclassname">paddle.trainer_config_helpers.activations.</code><code class="descname">ExpActivation</code></dt>
<dd><p>Exponential Activation.</p>
<div class="math">
\[f(z) = e^z.\]</div>
</dd></dl>

</div>
<div class="section" id="identityactivation">
<h2>IdentityActivation<a class="headerlink" href="#identityactivation" title="永久链接至标题">¶</a></h2>
<dl class="class">
<dt>
<em class="property">class </em><code class="descclassname">paddle.trainer_config_helpers.activations.</code><code class="descname">IdentityActivation</code></dt>
<dd><p>Identity Activation.</p>
<p>Just do nothing for output both forward/backward.</p>
</dd></dl>

</div>
<div class="section" id="linearactivation">
<h2>LinearActivation<a class="headerlink" href="#linearactivation" title="永久链接至标题">¶</a></h2>
<dl class="attribute">
<dt>
<code class="descclassname">paddle.trainer_config_helpers.activations.</code><code class="descname">LinearActivation</code></dt>
<dd><p><code class="xref py py-class docutils literal"><span class="pre">IdentityActivation</span></code> 的别名</p>
</dd></dl>

</div>
<div class="section" id="logactivation">
<h2>LogActivation<a class="headerlink" href="#logactivation" title="永久链接至标题">¶</a></h2>
<dl class="class">
<dt>
<em class="property">class </em><code class="descclassname">paddle.trainer_config_helpers.activations.</code><code class="descname">LogActivation</code></dt>
<dd><p>Logarithm Activation.</p>
<div class="math">
\[f(z) = log(z)\]</div>
</dd></dl>

</div>
<div class="section" id="squareactivation">
<h2>SquareActivation<a class="headerlink" href="#squareactivation" title="永久链接至标题">¶</a></h2>
<dl class="class">
<dt>
<em class="property">class </em><code class="descclassname">paddle.trainer_config_helpers.activations.</code><code class="descname">SquareActivation</code></dt>
<dd><p>Square Activation.</p>
<div class="math">
\[f(z) = z^2.\]</div>
</dd></dl>

</div>
<div class="section" id="sigmoidactivation">
<h2>SigmoidActivation<a class="headerlink" href="#sigmoidactivation" title="永久链接至标题">¶</a></h2>
<dl class="class">
<dt>
<em class="property">class </em><code class="descclassname">paddle.trainer_config_helpers.activations.</code><code class="descname">SigmoidActivation</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="softmaxactivation">
<h2>SoftmaxActivation<a class="headerlink" href="#softmaxactivation" title="永久链接至标题">¶</a></h2>
<dl class="class">
<dt>
<em class="property">class </em><code class="descclassname">paddle.trainer_config_helpers.activations.</code><code class="descname">SoftmaxActivation</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="sequencesoftmaxactivation">
<h2>SequenceSoftmaxActivation<a class="headerlink" href="#sequencesoftmaxactivation" title="永久链接至标题">¶</a></h2>
<dl class="class">
<dt>
<em class="property">class </em><code class="descclassname">paddle.trainer_config_helpers.activations.</code><code class="descname">SequenceSoftmaxActivation</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="reluactivation">
<h2>ReluActivation<a class="headerlink" href="#reluactivation" title="永久链接至标题">¶</a></h2>
<dl class="class">
<dt>
<em class="property">class </em><code class="descclassname">paddle.trainer_config_helpers.activations.</code><code class="descname">ReluActivation</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="breluactivation">
<h2>BReluActivation<a class="headerlink" href="#breluactivation" title="永久链接至标题">¶</a></h2>
<dl class="class">
<dt>
<em class="property">class </em><code class="descclassname">paddle.trainer_config_helpers.activations.</code><code class="descname">BReluActivation</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="softreluactivation">
<h2>SoftReluActivation<a class="headerlink" href="#softreluactivation" title="永久链接至标题">¶</a></h2>
<dl class="class">
<dt>
<em class="property">class </em><code class="descclassname">paddle.trainer_config_helpers.activations.</code><code class="descname">SoftReluActivation</code></dt>
<dd><p>SoftRelu Activation.</p>
</dd></dl>

</div>
<div class="section" id="tanhactivation">
<h2>TanhActivation<a class="headerlink" href="#tanhactivation" title="永久链接至标题">¶</a></h2>
<dl class="class">
<dt>
<em class="property">class </em><code class="descclassname">paddle.trainer_config_helpers.activations.</code><code class="descname">TanhActivation</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="stanhactivation">
<h2>STanhActivation<a class="headerlink" href="#stanhactivation" title="永久链接至标题">¶</a></h2>
<dl class="class">
<dt>
<em class="property">class </em><code class="descclassname">paddle.trainer_config_helpers.activations.</code><code class="descname">STanhActivation</code></dt>
<dd><p>Scaled Tanh Activation.</p>
<div class="math">
\[f(z) = 1.7159 * tanh(2/3*z)\]</div>
</dd></dl>

</div>
</div>


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