ceph/src/boost/libs/qvm/doc/accessing_vector_elements.html

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  14 <h1>QVM: Quaternions, Vectors, Matrices</h1>
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  16 <!-- Copyright (c) 2008-2016 Emil Dotchevski and Reverge Studios, Inc. -->
  17 <!-- Distributed under the Boost Software License, Version 1.0. (See accompanying -->
  18 <!-- file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) -->
  19 <div class="RenoIncludeDIV"><div class="RenoAutoDIV"><h3>Accessing Vector Elements</h3>
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  21 <div class="RenoIncludeDIV"><div class="RenoIncludeDIV"><p><span class="RenoEscape">&#35;<!--<wiki>`&#35;</wiki>--></span>include &lt;<span class="RenoLink"><a href="boost_qvm_vec_access_hpp.html">boost/qvm/vec_access.hpp</a></span>&gt;</p>
  22 <pre>namespace boost
  23 {
  24     namespace <span class="RenoLink"><a href="qvm.html">qvm</a></span>
  25     {
  26 <span class="RenoIncludeSPAN">        <span class="RenoIncludeSPAN">//Only <span class="RenoLink"><a href="SFINAE_enable_if.html">enabled if</a></span>:
  27         //  <span class="RenoLink"><a href="is_vec.html">is_vec</a></span>&lt;V&gt;::value
  28
  29         template &lt;int I,class V&gt; -unspecified-return-type- <span class="RenoLink">A</span>( V &amp; v );
  30         template &lt;class V&gt; -unspecified-return-type- A0( V &amp; v );
  31         template &lt;class V&gt; -unspecified-return-type- A1( V &amp; v );
  32         ...
  33         template &lt;class V&gt; -unspecified-return-type- A9( V &amp; v );
  34
  35         template &lt;class V&gt; -unspecified-return-type- X( V &amp; v );
  36         template &lt;class V&gt; -unspecified-return-type- Y( V &amp; v );
  37         template &lt;class V&gt; -unspecified-return-type- Z( V &amp; v );
  38         template &lt;class V&gt; -unspecified-return-type- W( V &amp; v );</span></span>
  39     }
  40 }</pre>
  41 </div></div><p>An expression of the form of <i><span class="RenoLink">A</span>&lt;I&gt;(v)</i> can be used to access the <i>I</i>-th element a vector object <i>v</i>. For example, the expression:</p>
  42 <pre><span class="RenoLink">A</span>&lt;1&gt;(v) *= 42;</pre>
  43 <p>can be used to multiply the element at index 1 (indexing in Boost QVM is always zero-based) of a vector <i>v</i> by 42.</p>
  44 <p>For convenience, there are also non-template overloads for <i>I</i> from 0 to 9; an alternative way to write the above expression is:</p>
  45 <pre>A1(v) *= 42;</pre>
  46 <p><i>X</i>, <i>Y</i>, <i>Z</i> and <i>W</i> act the same as <i>A0</i>/<i>A1</i>/<i>A2</i>/<i>A3</i>; yet another alternative way to write the above expression is:</p>
  47 <pre>Y(v) *= 42;</pre>
  48 </div><div class="RenoAutoDIV"><div class="RenoHR"><hr/></div>
  49 See also: <span class="RenoPageList"><a href="index.html">Boost QVM</a>&nbsp;| <a href="boost_qvm_vec_access_hpp.html">boost/qvm/vec_access.hpp</a>&nbsp;| <a href="known_quirks_and_issues.html">Known Quirks and Issues</a>&nbsp;| <a href="Synopsis.html">Synopsis</a></span>
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  51 <!-- Copyright (c) 2008-2016 Emil Dotchevski and Reverge Studios, Inc. -->
  52 <!-- Distributed under the Boost Software License, Version 1.0. (See accompanying -->
  53 <!-- file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) -->
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  58 <small>Copyright (c) 2008-2016 by Emil Dotchevski and Reverge Studios, Inc.<br/>
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