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<title>Performance</title>
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<div class="titlepage"><div><div><h2 class="title" style="clear: both">
<a name="math_toolkit.perf_over1"></a><a class="link" href="perf_over1.html" title="Performance">Performance</a>
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<p>
By and large the performance of this library should be acceptable for most
needs. However, often the library has to make a choice whether to be accurate
or fast and by default it chooses accuracy over speed. If you would rather
have fast rather than fully accurate routines, then refer to the <a class="link" href="../perf.html" title="Chapter 23. Performance">performance
section</a> for information and examples on how to achieve this.
</p>
<p>
In terms of the algorithms used, this library aims to use the same "best
of breed" algorithms as many other libraries: the principle difference
is that this library is implemented in C++ - taking advantage of all the abstraction
mechanisms that C++ offers - where as most traditional numeric libraries are
implemented in C or FORTRAN. Traditionally languages such as C or FORTRAN are
perceived as easier to optimise than more complex languages like C++, so in
a sense this library provides a good test of current compiler technology, and
the "abstraction penalty" - if any - of C++ compared to other languages.
</p>
<p>
The three most important things you can do to ensure the best performance from
this library are:
</p>
<div class="orderedlist"><ol class="orderedlist" type="1">
<li class="listitem">
Turn on your compilers optimisations: the difference between "release"
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
of 20</a>.
</li>
<li class="listitem">
Pick your compiler carefully: <a class="link" href="comp_compilers.html" title="Comparing Different Compilers">performance
differences of up to 8 fold</a> have been found between some Windows
compilers for example.
</li>
<li class="listitem">
Disable internal use of <code class="computeroutput"><span class="keyword">long</span> <span class="keyword">double</span></code>, this will reduce accuracy but typically
yield a 2x speedup on modern x64 hardware/compilers.
</li>
</ol></div>
<p>
The <a class="link" href="../perf.html" title="Chapter 23. Performance">performance section</a> contains more information
on the performance of this library, what you can do to fine tune it, and how
this library compares to some other open source alternatives.
</p>
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<div class="copyright-footer">Copyright © 2006-2021 Nikhar Agrawal, Anton Bikineev, Matthew Borland,
Paul A. Bristow, Marco Guazzone, Christopher Kormanyos, Hubert Holin, Bruno
Lalande, John Maddock, Evan Miller, Jeremy Murphy, Matthew Pulver, Johan Råde,
Gautam Sewani, Benjamin Sobotta, Nicholas Thompson, Thijs van den Berg, Daryle
Walker and Xiaogang Zhang<p>
Distributed under the Boost Software License, Version 1.0. (See accompanying
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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