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    <title>fast_length</title>
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        <a xmlns="http://www.w3.org/1999/xhtml" id="fast_length"></a>
        <h1>fast_length</h1>
        <p>
            Vector length.
        </p>
      </div>
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        <h2></h2>
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                <code xmlns="http://www.w3.org/1999/xhtml" class="funcdef">
                    <a class="link" href="scalarDataTypes.html" target="_top">float</a>
                    <strong class="fsfunc">                   
                        fast_length
                    </strong>
                (</code>
                <td><a xmlns="http://www.w3.org/1999/xhtml" class="link" href="vectorDataTypes.html" target="_top">float<em class="replaceable"><code>n</code></em></a> <var xmlns="http://www.w3.org/1999/xhtml" class="pdparam">p</var><code>)</code></td>
              </td>
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      </div>
      <div class="refsect1">
        <a id="description"></a>
        <h2>Description</h2>
        <p>
        Returns length of vector <code class="varname">p</code> computed as:</p>
        <p><a class="citerefentry" href="half_sqrt.html"><span class="citerefentry"><span class="refentrytitle">half_sqrt</span></span></a>(<code class="varname">p.x</code><sup>2</sup> + <code class="varname">p.y</code><sup>2</sup> + ...)
        </p>
      </div>
      <div class="refsect1">
        <a id="notes"></a>
        <h2>Notes</h2>
        <p>
            Built-in geometric functions operate component-wise and the description is per-component. 
            The type name <span class="type">float</span><em class="replaceable"><code>n</code></em> indicates that the function can take <span class="type">float</span>, 
            <span class="type">float2</span>, <span class="type">float3</span>, or <span class="type">float4</span> as the type 
            for the arguments.
        </p>
        <p>
            The built-in geometric functions are implemented using the round to nearest even rounding mode.
        </p>
        <p>
            The geometric functions can be implemented using contractions such as
            <a class="citerefentry" href="mad.html"><span class="citerefentry"><span class="refentrytitle">mad</span></span></a> or 
            <a class="citerefentry" href="fma.html"><span class="citerefentry"><span class="refentrytitle">fma</span></span></a>.
        </p>
      </div>
      <div class="refsect1">
        <a id="specification"></a>
        <h2>Specification</h2>
        <p>
            <img src="pdficon_small1.gif" />
                                                 
            <a href="http://www.khronos.org/registry/cl/specs/opencl-1.1.pdf#page=216" target="OpenCL Spec">OpenCL Specification</a>
        </p>
      </div>
      <div class="refsect1">
        <a id="seealso"></a>
        <h2>Also see</h2>
        <p>
            <a class="citerefentry" href="geometricFunctions.html"><span class="citerefentry"><span class="refentrytitle">Geometric Functions</span></span></a> 
        </p>
      </div>
      <div xmlns="" class="refsect3" lang="en" xml:lang="en"><a xmlns="http://www.w3.org/1999/xhtml" id="Copyright"></a><h4 xmlns="http://www.w3.org/1999/xhtml"></h4><img xmlns="http://www.w3.org/1999/xhtml" src="KhronosLogo.jpg" /><p xmlns="http://www.w3.org/1999/xhtml"></p>Copyright © 2007-2010 The Khronos Group Inc.
Permission is hereby granted, free of charge, to any person obtaining a
copy of this software and/or associated documentation files (the
"Materials"), to deal in the Materials without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Materials, and to
permit persons to whom the Materials are furnished to do so, subject to
the condition that this copyright notice and permission notice shall be included
in all copies or substantial portions of the Materials.
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