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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&#160;16.&#160;Performance">performance
section</a> for information and examples on how to achieve this.
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<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.
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<p>
The three most important things you can do to ensure the best performance from
this library are:
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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&#160;16.&#160;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.
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Benjamin Sobotta, Thijs van den Berg, Daryle Walker and Xiaogang Zhang<p>
Distributed under the Boost Software License, Version 1.0. (See accompanying
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