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<title>Sets the activation function for supplied neuron and layer</title>
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<h1 class="refname">fann_set_activation_function</h1>
<p class="verinfo">(PECL fann >= 1.0.0)</p><p class="refpurpose"><span class="refname">fann_set_activation_function</span> — <span class="dc-title">Sets the activation function for supplied neuron and layer</span></p>
</div>
<div class="refsect1 description" id="refsect1-function.fann-set-activation-function-description">
<h3 class="title">Description</h3>
<div class="methodsynopsis dc-description">
<span class="type">bool</span> <span class="methodname"><strong>fann_set_activation_function</strong></span>
( <span class="methodparam"><span class="type">resource</span> <code class="parameter">$ann</code></span>
, <span class="methodparam"><span class="type">int</span> <code class="parameter">$activation_function</code></span>
, <span class="methodparam"><span class="type">int</span> <code class="parameter">$layer</code></span>
, <span class="methodparam"><span class="type">int</span> <code class="parameter">$neuron</code></span>
)</div>
<p class="para rdfs-comment">
Set the activation function for neuron number <em>neuron</em> in layer number
<em>layer</em>, counting the input layer as layer 0.
</p>
<p class="para">
It is not possible to set activation functions for the neurons in the input layer.
</p>
<p class="para">
When choosing an activation function it is important to note that the activation functions have different range.
<strong><code>FANN_SIGMOID</code></strong> is e.g. in the 0 - 1 range while <strong><code>FANN_SIGMOID_SYMMETRIC</code></strong> is
in the -1 - 1 range and <strong><code>FANN_LINEAR</code></strong> is unbound.
</p>
<p class="para">
The supplied activation_function value must be
one of the <a href="fann.constants.html#constants.fann-activation-funcs" class="link">activation functions</a> constants.
</p>
<p class="para">
The return value is one of the <a href="fann.constants.html#constants.fann-train" class="link">activation functions</a> constants.
</p>
</div>
<div class="refsect1 parameters" id="refsect1-function.fann-set-activation-function-parameters">
<h3 class="title">Parameters</h3>
<dl>
<dt>
<span class="term"><em><code class="parameter">ann</code></em></span>
<dd>
<p class="para">Neural network <span class="type"><a href="language.types.resource.html" class="type resource">resource</a></span>.</p>
</dd>
</dt>
<dt>
<span class="term"><em><code class="parameter">activation_function</code></em></span>
<dd>
<p class="para">
The <a href="fann.constants.html#constants.fann-activation-funcs" class="link">activation functions</a> constant.
</p>
</dd>
</dt>
<dt>
<span class="term"><em><code class="parameter">layer</code></em></span>
<dd>
<p class="para">
Layer number.
</p>
</dd>
</dt>
<dt>
<span class="term"><em><code class="parameter">neuron</code></em></span>
<dd>
<p class="para">
Neuron number.
</p>
</dd>
</dt>
</dl>
</div>
<div class="refsect1 returnvalues" id="refsect1-function.fann-set-activation-function-returnvalues">
<h3 class="title">Return Values</h3>
<p class="para">Returns <strong><code>TRUE</code></strong> on success, or <strong><code>FALSE</code></strong> otherwise.</p>
</div>
<div class="refsect1 seealso" id="refsect1-function.fann-set-activation-function-seealso">
<h3 class="title">See Also</h3>
<p class="para">
<ul class="simplelist">
<li class="member"> <span class="function"><a href="function.fann-set-activation-function-layer.html" class="function" rel="rdfs-seeAlso">fann_set_activation_function_layer()</a> - Sets the activation function for all the neurons in the supplied layer.</span></li>
<li class="member"> <span class="function"><a href="function.fann-set-activation-function-hidden.html" class="function" rel="rdfs-seeAlso">fann_set_activation_function_hidden()</a> - Sets the activation function for all of the hidden layers</span></li>
<li class="member"> <span class="function"><a href="function.fann-set-activation-function-output.html" class="function" rel="rdfs-seeAlso">fann_set_activation_function_output()</a> - Sets the activation function for the output layer</span></li>
<li class="member"> <span class="function"><a href="function.fann-set-activation-steepness.html" class="function" rel="rdfs-seeAlso">fann_set_activation_steepness()</a> - Sets the activation steepness for supplied neuron and layer number</span></li>
<li class="member"> <span class="function"><a href="function.fann-get-activation-function.html" class="function" rel="rdfs-seeAlso">fann_get_activation_function()</a> - Returns the activation function</span></li>
</ul>
</p>
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