o /** @mainpage Eigen

<h2>Table of contents</h2>
<a href="#overview">Overview</a><br/>
<a href="#license">License</a><br/>
<a href="#features">Features</a><br/>
<a href="#todo">To-do wiki</a><br/>
<a href="#compiler_support">Compiler Support</a><br/>
<a href="#news">News</a><br/>
<a href="#download">Download</a><br/>
<a href="#kde">Relation to KDE</a><br/>
<a href="#examples">Examples</a><br/>
<a href="#applications">Applications using Eigen</a><br/>
<a href="#authors">Authors</a><br/>
<a href="#contact">Contact us</a><br/>
<a href="#mailinglist">Mailing list</a><br/>

<a name="overview"></a>
<h2>Overview</h2>

Eigen is a C++ template library for vector and matrix math, a.k.a. linear algebra. It aims to concile speed, ease of use, and completeness.

<a name="license"></a>
<h2>License</h2>

 Eigen is distributed under the GPL, version 2 or later, but with an <a href="#exception">exception allowing any software to use it</a>. Thus, to the question
"Can my own project use Eigen?", the answer is a definite <b>yes</b>.

Eigen's <a href="#exception">exception</a> is modeled after the one of the GNU C++ Standard Library, but is simpler and more liberal.

This is similar to the LGPL in spirit. The reason why we don't use the LGPL is that, as of version 2, it doesn't make sense for a pure template library like Eigen, where all the code is in headers.

<a name="features"></a>
<h2>Features</h2>

WARNING: this alpha release is NOT feature complete -- far from it! It contains only the Core module, while several other modules are planned.

Here are general features of Eigen and more specific features of the Core module:

<ul>
  <li><a href="http://ubiety.uwaterloo.ca/~tveldhui/papers/Expression-Templates/exprtmpl.html">Expression templates</a> everywhere. This is an optimization (elimination of temporaries, lazy evaluation), but more importantly this allows for a much nicer API, especially as Eigen supports lvalue expressions. For example, the following is valid with Eigen and compiles to optimized code:
  \code matrix.row(i) += factor * matrix.row(j); \endcode</li>
  <li>Both fixed-size and dynamic-size objects are supported, with uniform API,
      in a way that allows Eigen to make
      all usual optimizations in the case of fixed size, such as loop unrolling.</li>
  <li>Both column-vectors and row-vectors are supported, as special cases of matrices.</li>
  <li>The following scalar types are supported and well tested: \c int, \c float, \c double,
      \c std::complex<float>, \c std::complex<double>. </li>
</ul>

<a name="todo"></a>
<h2>To-do wiki</h2>

The To-do wiki for Eigen is here: <a href="http://techbase.kde.org/index.php?title=Projects/Eigen/TODO">http://techbase.kde.org/index.php?title=Projects/Eigen/TODO</a>.

<a name="compiler_support"></a>
<h2>Compiler Support</h2>

Eigen is standard C++98 and so should theoretically be compatible with any compliant compiler. Of course, in practice, things are slightly different.

Eigen is well tested with recent versions of GCC and gives very good performance with GCC 4.2. For some reason the performance is not so great with GCC 4.1.

Eigen is also well tested on ICC, and gives even better performance with it than with GCC 4.2.

<a name="news"></a>
<h2>News</h2>

If you want to stay informed of Eigen news and releases, please subscribe to our <a href="#mailinglist">mailing list</a>. You can also browse the <a href="http://listengine.tuxfamily.org/lists.tuxfamily.org/eigen/">archive</a>.

<a name="download"></a>
<h2>Download</h2>
The source code of the latest release is here: <a href="http://download.tuxfamily.org/eigen/eigen-2.0-alpha2.tar.gz">eigen-2.0-alpha2.tar.gz</a><br/>

Alternatively, you can checkout the development tree by anonymous svn, by doing:
<pre>svn co svn://anonsvn.kde.org/home/kde/branches/work/eigen2</pre>
or view it online at this address:
<a href="http://websvn.kde.org/branches/work/eigen2">http://websvn.kde.org/branches/work/eigen2</a>

<a name="kde"></a>
<h2>Relation to KDE</h2>

First of all: Eigen doesn't have any dependency. In particular, it doesn't depend on any part of KDE or on Qt.<br/>

Eigen is part of the KDE project, in the sense that:
<ul>
  <li>Its <a href="http://websvn.kde.org/trunk/kdesupport/eigen/">development tree</a> is hosted in the <a href="http://websvn.kde.org">KDE repository</a>.</li>
  <li>It has been founded by, and is developed by KDE people.</li>
  <li>It has originally been designed for the needs of KDE applications, especially <a href="http://edu.kde.org/kalzium">Kalzium</a>.</li>
</ul>
However, we quickly realized that Eigen could be useful for non-KDE projects, whence our decision to make sure that it has no dependency on KDE or Qt.

Although Eigen itself doesn't have any dependency, the unit-tests require Qt.

<a name="examples"></a>
<h2>Examples</h2>

There are a lot of small examples throughout the documentation. TODO: write more interesting,
standalone "demos".

<a name="applications"></a>
<h2>Applications using Eigen</h2>

TODO: update this section; make web links

Currently: Kalzium, Avogadro, KSpread(a bit), Krita(a bit)
Planned: much more use in KOffice 2.1, Step (if we make Eigen good enough!)

Please tell us if you know of other interesting projects using Eigen!

<a name="authors"></a>
<h2>Authors</h2>

<b>Main Developer:</b> Benoit Jacob (jacob at math jussieu fr)

<b>Contributors during the Eigen 2 development process:</b>
<ul>
  <li>Gael Guennebaud (gael guennebaud at gmail com) : Intel compiler (ICC) support
  <li>Christian Mayer (mail at christianmayer de) : reviewed the source code, made many useful suggestions</li>
  <li>Michael Olbrich (michael olbrich at gmx net) : initial loop-unrolling metaprogram</li>
  <li>and thanks to everyone on the <a href="#mailinglist">mailing list</a> for your input!
</ul>

<a name="contact"></a>
<h2>Contact us</h2>

The best way to contact us is by means of our <a href="#mailinglist">mailing list</a>.<br/>
IRC Channel: \#eigen on Freenode.<br/>
Website (you're here): <a href="http://eigen.tuxfamily.org">http://eigen.tuxfamily.org</a><br/>

<a name="mailinglist"></a>
<h2>Mailing list</h2>

The Mailing list for Eigen is: eigen at lists tuxfamily org.<br/>

To subscribe, send a mail with subject "subscribe" to eigen-request at lists tuxfamily org.<br/>
To unsubscribe, send a mail with subject "unsubscribe" to eigen-request at lists tuxfamily org.<br/>

You can also browse the <a href="http://listengine.tuxfamily.org/lists.tuxfamily.org/eigen/">archive</a>.

<a name="exception"></a>
<h2>Exception to the GPL</h2>
Eigen is licensed under the GNU GPL, version 2 or later, plus the following exception, which is replicated into each of the source files of Eigen:
<pre>
// As a special exception, if other files instantiate templates or use macros
// or inline functions from this file, or you compile this file and link it
// with other works to produce a work based on this file, this file does not
// by itself cause the resulting work to be covered by the GNU General Public
// License. This exception does not invalidate any other reasons why a work
// based on this file might be covered by the GNU General Public License.
</pre>

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