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<div class="section" lang="en">
<div class="titlepage"><div><div><h2 class="title" style="clear: both">
<a name="boost_icl.implementation"></a><a class="link" href="implementation.html" title="Implementation">Implementation</a>
</h2></div></div></div>
<div class="toc"><dl>
<dt><span class="section"><a href="implementation.html#boost_icl.implementation.iterative_size">Iterative size</a></span></dt>
<dt><span class="section"><a href="implementation/complexity.html">Complexity</a></span></dt>
<dt><span class="section"><a href="implementation/inplace_and_infix_operators.html">Inplace
and infix operators</a></span></dt>
</dl></div>
<p>
The <a class="link" href="interface.html" title="Interface">previous section</a> gave an overview
over the interface of the <span class="bold"><strong>icl</strong></span> outlining <a class="link" href="interface.html#boost_icl.interface.class_templates" title="Class templates">class templates</a>, <a class="link" href="interface/associated_types.html" title="Associated Types">associated types</a> and
polymorphic <a class="link" href="interface/function_synopsis.html" title="Function Synopsis">functions
and operators</a>. In preparation to the <a class="link" href="function_reference.html" title="Function Reference">next
section</a>, that describes the <span class="bold"><strong>icl's</strong></span> polymorphic
functions in more detail together with <span class="emphasis"><em><span class="bold"><strong>complexity
characteristics</strong></span></em></span>, this section summarizes some general
information on implementation and performance.
</p>
<a name="boost_icl.implementation.stl_based_implementation"></a><h6>
<a name="id1124222"></a>
<a class="link" href="implementation.html#boost_icl.implementation.stl_based_implementation">STL based
implementation</a>
</h6>
<p>
The <span class="bold"><strong>implementation</strong></span> of the <span class="bold"><strong>icl's</strong></span>
containers is based on <span class="bold"><strong>std::set</strong></span> and <span class="bold"><strong>std::map</strong></span>. So the underlying data structure of interval
containers is a red black tree of intervals or interval value pairs. The element
containers <a href="http://www.cplusplus.com/reference/stl/set/" target="_top"><code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">set</span></code>
</a> and <code class="computeroutput"><a class="link" href="../boost/icl/map.html" title="Class template map">icl::map</a></code> are wrapper
classes of <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">set</span></code> and <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">map</span></code>. Interval
containers are then using <a href="http://www.cplusplus.com/reference/stl/set/" target="_top"><code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">sets</span></code></a>
of intervals or <code class="computeroutput"><a class="link" href="../boost/icl/map.html" title="Class template map">icl::maps</a></code> of interval
value pairs as implementing containers. So all the <span class="emphasis"><em><span class="bold"><strong>complexity
characteristics</strong></span></em></span> of icl containers are based on and limited
by the <span class="emphasis"><em><span class="bold"><strong>red-black tree implementation</strong></span></em></span>
of the underlying std::AssociativeContainers.
</p>
<div class="section" lang="en">
<div class="titlepage"><div><div><h3 class="title">
<a name="boost_icl.implementation.iterative_size"></a><a class="link" href="implementation.html#boost_icl.implementation.iterative_size" title="Iterative size">Iterative size</a>
</h3></div></div></div>
<p>
Throughout the documentation on complexity, big <span class="emphasis"><em>O</em></span> expressions
like <span class="emphasis"><em>O(n)</em></span> or <span class="emphasis"><em>O(m log n)</em></span> refer to
container sizes <span class="emphasis"><em>n</em></span> and <span class="emphasis"><em>m</em></span>. In this
documentation these sizes <span class="emphasis"><em><span class="bold"><strong>do not</strong></span></em></span>
denote to the familiar <code class="computeroutput"><span class="identifier">size</span></code>
function that returns the <span class="emphasis"><em><span class="bold"><strong>number of elements</strong></span></em></span>
of a container. Because for an interval container
</p>
<pre class="programlisting"><span class="identifier">interval_set</span><span class="special"><</span><span class="keyword">int</span><span class="special">></span> <span class="identifier">mono</span><span class="special">;</span>
<span class="identifier">mono</span> <span class="special">+=</span> <span class="identifier">interval</span><span class="special"><</span><span class="keyword">int</span><span class="special">>::</span><span class="identifier">closed</span><span class="special">(</span><span class="number">1</span><span class="special">,</span><span class="number">5</span><span class="special">);</span> <span class="comment">// {[1 ... 5]}
</span><span class="identifier">mono</span><span class="special">.</span><span class="identifier">size</span><span class="special">()</span> <span class="special">==</span> <span class="number">5</span><span class="special">;</span> <span class="comment">// true, 5 elements
</span><span class="identifier">mono</span><span class="special">.</span><span class="identifier">interval_count</span><span class="special">()</span> <span class="special">==</span> <span class="number">1</span><span class="special">;</span> <span class="comment">// true, only one interval
</span></pre>
<p>
</p>
<p>
it's size and the number of contained intervals is usually different. To
refer uniformly to a <span class="emphasis"><em>size</em></span> that matters for iteration,
which is the decisive kind of size concerning algorithmic behavior there
is a function
</p>
<pre class="programlisting"><span class="keyword">bool</span> <span class="identifier">T</span><span class="special">::</span><span class="identifier">iterative_size</span><span class="special">()</span><span class="keyword">const</span><span class="special">;</span> <span class="comment">// Number of entities that can be iterated over.
</span></pre>
<p>
for all element and interval containers of the icl. So for complexity statements
throughout the icl's documentation the sizes will be <code class="computeroutput"><span class="identifier">iterative_sizes</span></code>
and big <span class="emphasis"><em>O</em></span> expressions like <span class="emphasis"><em>O(m log n)</em></span>
will refer to sizes
</p>
<pre class="programlisting"><span class="identifier">n</span> <span class="special">=</span> <span class="identifier">y</span><span class="special">.</span><span class="identifier">iterative_size</span><span class="special">();</span>
<span class="identifier">m</span> <span class="special">=</span> <span class="identifier">x</span><span class="special">.</span><span class="identifier">iterative_size</span><span class="special">();</span>
</pre>
<p>
for containers <code class="computeroutput"><span class="identifier">y</span></code> and <code class="computeroutput"><span class="identifier">x</span></code>. Note that
</p>
<pre class="programlisting"><span class="identifier">iterative_size</span></pre>
<p>
refers to the primary entities, that we can iterate over. For interval containers
these are intervals or segments.
</p>
<pre class="programlisting"><span class="identifier">Itervative_size</span></pre>
<p>
never refers to element iteration for interval containers.
</p>
</div>
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<td align="right"><div class="copyright-footer">Copyright © 2007 -2010 Joachim Faulhaber<br>Copyright © 1999 -2006 Cortex Software GmbH<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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