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								<title>Performance Overview</title>
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								<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../../boost.png"></td>
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								<div class="titlepage"><div><div><h2 class="title" style="clear: both">
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								<a name="math_toolkit.perf_over2"></a><a class="link" href="perf_over2.html" title="Performance Overview">Performance Overview</a>
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								</h2></div></div></div>
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								<p>
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								      By and large the performance of this library should be acceptable for most
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								      needs. However, often the library has to make a choice whether to be accurate
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								      or fast and by default it chooses accuracy over speed. If you would rather
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								      have fast rather than fully accurate routines, then refer to the <a class="link" href="../perf.html" title="Chapter 16. Performance">performance
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								      section</a> for information and examples on how to achieve this.
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								    </p>
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								<p>
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								      In terms of the algorithms used, this library aims to use the same "best
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								      of breed" algorithms as many other libraries: the principle difference
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								      is that this library is implemented in C++ - taking advantage of all the abstraction
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								      mechanisms that C++ offers - where as most traditional numeric libraries are
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								      implemented in C or FORTRAN. Traditionally languages such as C or FORTRAN are
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								      perceived as easier to optimise than more complex languages like C++, so in
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								      a sense this library provides a good test of current compiler technology, and
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								      the "abstraction penalty" - if any - of C++ compared to other languages.
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								    </p>
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								<p>
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								      The three most important things you can do to ensure the best performance from
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								      this library are:
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								    </p>
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								<div class="orderedlist"><ol class="orderedlist" type="1">
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								          Turn on your compilers optimisations: the difference between "release"
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								          and "debug" builds can easily be a <a class="link" href="getting_best.html" title="Getting the Best Performance from this Library: Compiler and Compiler Options">factor
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								          of 20</a>.
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								        </li>
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								<li class="listitem">
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								          Pick your compiler carefully: <a class="link" href="comp_compilers.html" title="Comparing Different Compilers">performance
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								          differences of up to 8 fold</a> have been found between some Windows
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								          compilers for example.
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								        </li>
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								<li class="listitem">
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								          Disable internal use of <code class="computeroutput"><span class="keyword">long</span> <span class="keyword">double</span></code>, this will reduce accuracy but typically
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								          yield a 2x speedup on modern x64 hardware/compilers.
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								        </li>
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								</ol></div>
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								<p>
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								      The <a class="link" href="../perf.html" title="Chapter 16. Performance">performance section</a> contains more information
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								      on the performance of this library, what you can do to fine tune it, and how
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								      this library compares to some other open source alternatives.
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								    </p>
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								<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
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								<td align="right"><div class="copyright-footer">Copyright © 2006-2010, 2012-2014 Nikhar Agrawal,
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								      Anton Bikineev, Paul A. Bristow, Marco Guazzone, Christopher Kormanyos, Hubert
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								      Holin, Bruno Lalande, John Maddock, Jeremy Murphy, Johan Råde, Gautam Sewani,
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								      Benjamin Sobotta, Thijs van den Berg, Daryle Walker and Xiaogang Zhang<p>
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								        Distributed under the Boost Software License, Version 1.0. (See accompanying
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								        file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
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