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    <title>atan</title>
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    <meta name="keywords" content="atan, atan2, atanh, atanpi, atan2pi" />
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    <div class="refentry">
      <a id="id-1"></a>
      <div class="titlepage"></div>
      <div xmlns="" class="refnamediv">
        <a xmlns="http://www.w3.org/1999/xhtml" id="atan"></a>
        <h1>atan, atan2, atanh, atanpi, atan2pi </h1>
        <p>
            Tangent functions.
        </p>
      </div>
      <div class="refsynopsisdiv">
        <h2></h2>
        <div class="funcsynopsis">
          <table xmlns="" border="0" summary="Function synopsis" cellspacing="0" cellpadding="0">
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              <td>
                <code xmlns="http://www.w3.org/1999/xhtml" class="funcdef">
                    gentype
                    <strong class="fsfunc">                   
                        atan
                    </strong>
                (</code>
                <td>gentype <var xmlns="http://www.w3.org/1999/xhtml" class="pdparam">y_over_x</var><code>)</code></td>
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          </table>
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        <div class="funcsynopsis">
          <table xmlns="" border="0" summary="Function synopsis" cellspacing="0" cellpadding="0">
            <tr valign="bottom">
              <td>
                <code xmlns="http://www.w3.org/1999/xhtml" class="funcdef">
                    gentype
                    <strong class="fsfunc">                   
                        atan2
                    </strong>
                (</code>
                <td>gentype <var xmlns="http://www.w3.org/1999/xhtml" class="pdparam">y</var>, </td>
              </td>
            </tr>
            <tr valign="top">
              <td> </td>
              <td>gentype <var xmlns="http://www.w3.org/1999/xhtml" class="pdparam">x</var><code>)</code></td>
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                <code xmlns="http://www.w3.org/1999/xhtml" class="funcdef">
                    gentype
                    <strong class="fsfunc">                   
                        atanh
                    </strong>
                (</code>
                <td>gentype <var xmlns="http://www.w3.org/1999/xhtml" class="pdparam"></var><code>)</code></td>
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              <td>
                <code xmlns="http://www.w3.org/1999/xhtml" class="funcdef">
                    gentype
                    <strong class="fsfunc">                   
                        atanpi
                    </strong>
                (</code>
                <td>gentype <var xmlns="http://www.w3.org/1999/xhtml" class="pdparam">x</var><code>)</code></td>
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            <tr valign="bottom">
              <td>
                <code xmlns="http://www.w3.org/1999/xhtml" class="funcdef">
                    gentype
                    <strong class="fsfunc">                   
                        atan2pi
                    </strong>
                (</code>
                <td>gentype <var xmlns="http://www.w3.org/1999/xhtml" class="pdparam">y</var>, </td>
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      </div>
      <div class="refsect1">
        <a id="description"></a>
        <h2>Description</h2>
        <p><code class="function">atan</code> is the arc tangent function. </p>
        <p><code class="function">atan2</code> is the arc tangent of <code class="varname">y</code> / <code class="varname">x</code>. </p>
        <p><code class="function">atanh</code> is the hyperbolic arc tangent function. </p>
        <p><code class="function">atanpi</code> computes <code class="function">atan</code> (<code class="varname">x</code>) / π. </p>
        <p><code class="function">atan2pi</code> computes <code class="function">atan2</code> (<code class="varname">y</code>, <code class="varname">x</code>) / π. </p>
      </div>
      <div class="refsect1">
        <a id="notes"></a>
        <h2>Notes</h2>
        <p>
        The built-in math functions are categorized into the following:
    </p>
        <p>
      </p>
        <div class="itemizedlist">
          <ul class="itemizedlist" style="list-style-type: disc; ">
            <li class="listitem">A list of built-in functions that have scalar or vector argument versions, and,</li>
            <li class="listitem">A list of built-in functions that only take scalar float arguments.</li>
          </ul>
        </div>
        <p>
    </p>
        <p>
        The vector versions of the math functions operate
        component-wise.  The description is per-component.
    </p>
        <p>
    The built-in math functions are not affected by the prevailing rounding mode in the calling
    environment, and always return the same value as they would if called with the round to
    nearest even rounding mode.
  </p>
        <p>
    The built-in math functions take scalar or vector arguments. For any specific use of these
    function, the actual type has to be the same for all arguments and the return type unless
    otherwise specified.
  </p>
        <p>
    The generic type name <span class="type">gentype</span> is used to indicate that the function can
    take <span class="type">float</span>, <span class="type">float2</span>, <span class="type">float3</span>, <span class="type">float4</span>,
    <span class="type">float8</span>, <span class="type">float16</span>, <span class="type">double</span>, <span class="type">double2</span>,
    <span class="type">double3</span>, <span class="type">double4</span>, <span class="type">double8</span>, or <span class="type">double16</span>
    as the type for the arguments.
  </p>
        <p>
    If extended with <a class="citerefentry" href="cl_khr_fp16.html"><span class="citerefentry"><span class="refentrytitle">cl_khr_fp16</span></span></a>,
    generic type name <span class="type">gentype</span> may indicate <span class="type">half</span> and
    <span class="type">half{2|3|4|8|16}</span> as arguments and return values.
  </p>
        <p>
    The generic type name <span class="type">gentypef</span> is used to indicate that the function can
    take <span class="type">float</span>, <span class="type">float2</span>, <span class="type">float3</span>, <span class="type">float4</span>,
    <span class="type">float8</span>, or <span class="type">float16</span> as the type for the arguments.
  </p>
        <p>
    The generic type name <span class="type">gentyped</span> is used to indicate that the function can take
    <span class="type">double</span>, <span class="type">double2</span>, <span class="type">double3</span>, <span class="type">double4</span>,
    <span class="type">double8</span>, or <span class="type">double16</span> as the type for the arguments.
  </p>
      </div>
      <div class="refsect1">
        <a id="specification"></a>
        <h2>Specification</h2>
        <p>
            <img src="pdficon_small1.gif" />
                                                 
            <a href="https://www.khronos.org/registry/cl/specs/opencl-2.0-openclc.pdf#page=71" target="OpenCL Spec">OpenCL Specification</a>
        </p>
      </div>
      <div class="refsect1">
        <a id="seealso"></a>
        <h2>Also see</h2>
        <p>
            <a class="citerefentry" href="mathFunctions.html"><span class="citerefentry"><span class="refentrytitle">Math 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 © 2007-2013 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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