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== Download ==
 
== Download ==
  
===Mercurial===
 
 
Here is the source tarball for the latest stable release:
 
Here is the source tarball for the latest stable release:
 
[http://bitbucket.org/eigen/eigen2/get/0016da146dc5.zip zip] or  
 
[http://bitbucket.org/eigen/eigen2/get/0016da146dc5.zip zip] or  

Revision as of 12:54, 18 May 2009

Date: April 14, 2009

Eigen 2.0.1 released!

Eigen 2.1 is under development, scheduled for July.


Overview

Eigen is a C++ template library for linear algebra: vectors, matrices, and related algorithms. It is:

  • Versatile. (See modules and tutorial). Eigen handles, without code duplication, and in a completely integrated way:
    • both fixed-size and dynamic-size matrices and vectors.
    • both dense and sparse (the latter is still experimental) matrices and vectors.
    • both plain matrices/vectors and abstract expressions.
    • both column-major (the default) and row-major matrix storage.
    • both basic matrix/vector manipulation and many more advanced, specialized modules providing algorithms for linear algebra, geometry, quaternions, or advanced array manipulation.
  • Fast. (See benchmark).
    • Expression templates allow to intelligently remove temporaries and enable lazy evaluation, when that is appropriate -- Eigen takes care of this automatically and handles aliasing too in most cases.
    • Explicit vectorization is performed for the SSE (2 and later) and AltiVec instruction sets, with graceful fallback to non-vectorized code. Expression templates allow to perform these optimizations globally for whole expressions.
    • With fixed-size objects, dynamic memory allocation is avoided, and the loops are unrolled when that makes sense.
    • For large matrices, special attention is paid to cache-friendliness.
  • Elegant. (See API showcase). The API is extremely clean and expressive, thanks to expression templates. Implementing an algorithm on top of Eigen feels like just copying pseudocode. You can use complex expressions and still rely on Eigen to produce optimized code: there is no need for you to manually decompose expressions into small steps.
  • Compiler-friendy. Eigen has very reasonable compilation times at least with GCC, compared to other C++ libraries based on expression templates and heavy metaprogramming. Eigen is also standard C++ and supports various compilers.

FAQ

Frequently asked questions are here.

Documentation

The documentation is here.

It includes a Tutorial.

To learn about the internals of Eigen, read this example and check out this page about some of Eigen's internal mechanisms: EigenInternals.

Requirements

Eigen doesn't have any dependency. It just uses a little the C++ standard library.

It uses the CMake build system. However, this is only to build the documentation and unit-tests, and to automate installation. If you just want to use Eigen, you can use the header files right away. There is no binary library to link to (pure template library), and no configured header file.

Download

Here is the source tarball for the latest stable release: zip or b-zip2 archive

Here is the Mercurial command to check out the development tree (currently heading toward 2.1):

hg clone https://bitbucket.org/eigen/eigen2/

You can also view it online here.

Here is the Mercurial command to check out the 2.0 stable branch:

hg clone --rev 2.0 https://bitbucket.org/eigen/eigen2/

Here is the Mercurial command to check out the 2.0.1 stable tag (equivalent to the above tarball):

hg clone --rev 2.0.1 https://bitbucket.org/eigen/eigen2/

License

Eigen is Free Software. It is licensed under the LGPL3+. As an alternative license choice, Eigen is also licensed under the GPL2+.

Virtually any software may use Eigen. Even closed-source software may use Eigen without having to disclose its own source code.

See the Licensing FAQ.

Credits

Core developers (in alphabetical order):

Contributors (in alphabetical order):

  • David Benjamin (the owls)
  • Armin Berres (MSVC compatibility fixes, GCC warning fixes)
  • Rohit Garg (vectorized quaternion and cross products, improved integer product)
  • Daniel Gómez (several improvements, especially in the Sparse module)
  • Hauke Heibel (MSVC compatibility fixes, aligned_allocator fixes)
  • Moritz Lenz (allow solving transposed problem with SuperLU)
  • Konstantinos Margaritis (Altivec vectorization)
  • Ricard Marxer (Reverse, redux improvements, the count() method, some dox)
  • Christian Mayer (early code review and input in technical/design discussions)
  • Frank Meier-Dörnberg (MSVC compatibility fixes)
  • Keir Mierle (LDLt decomposition, some dox, a bugfix)
  • Michael Olbrich (initial meta loop unroller and early benchmarking)
  • Stjepan Rajko (a MSVC compatibility fix)
  • Kenneth Riddile (aligned STL allocator, MSVC compatibility fixes, exception throwing)
  • Alex Stapleton (std::vector specialization)

Special thanks to Tuxfamily for the wonderful quality of their services!

Compiler support

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 being successfully used with the following compilers:

  • GCC, version 3.3 and newer. Very good performance with GCC 4.2 and newer.
  • MSVC (Visual Studio), 2005 and newer. Vectorization is enabled with 2008 and newer.
  • ICC, recent versions. Very good performance.
  • MinGW, recent versions. Performance is poor because MinGW uses GCC 3. This problem will go away whenever MinGW upgrades to GCC 4. If this is an important issue for you, you can try the unofficial drop-in replacements for gcc4 in mingw. In gentoo, the mingw32 cross-compiler targeting windows is using gcc-4.3.

Here are some comments about GCC compiler flags.

  • At least some optimization is mandatory to get even remotely decent speed. -O1 gives something decent for a debug mode, at 30-60% of the optimal speed. -O2 generally gives optimal speed. -O3 does not have much advantages over -O2, in our experience.
  • Debugging info with -g (equivalently -g2) can increase dramatically the executable file's size. This is always the case, but even more so with Eigen.
  • Disabling asserts, by defining -DNDEBUG or -DEIGEN_NO_DEBUG, improves performance in some cases.
  • Vectorization is automatically enabled if a SIMD instruction set is enabled by the compiler. On the x86 platform, SSE2 is not enabled by default and you need to pass the -msse2 option.

Projects using Eigen

Science

Robotics and engineering

Computer Graphics

  • VcgLib, an opensource C++ template library for the manipulation and processing of triangle and tetrahedral meshes. (switched from home made math classes)
  • MeshLab, an opensource software for the processing and editing of unstructured 3D triangular meshes and point cloud. (switched from vcglib's math classes)
  • Expe, an experimental framework for the rapid prototyping of graphics applications. No release yet, but it uses 90% of Eigen's features. (switched from home made math classes).
  • libmv, an opensource structure from motion library. (switched from FLENS)

KDE (our origins!)

  • Various KDE related projects such as Step, the Mandelbrot wallpaper plugin, some screensavers, kgllib, kglengine2d, solidkreator, etc.
  • Koffice2 (KDE's office suite), in particular Krita, the painting and image editing module. Eigen is also used a bit by KSpread, the spreadsheet module, for matrix functions such as MINVERSE, MMULT, MDETERM.
  • Kalzium uses Eigen indirectly through the aforementioned Avogadro library.

If you are aware of some interesting projects using Eigen, please send us a message or directly edit this wiki page !

Get support

Need help using Eigen? Try this:

  • The users forum is your best resource.
  • Our IRC channel is #eigen on irc.freenode.net.
  • Want to discuss something with the developers? Think you've found a bug? Use our mailing list.

Mailing list

Our mailing list is the central point for discussion of Eigen development, bugs, feature requests, etc.

  • To subscribe, send a mail with subject "subscribe" to eigen-request at lists tuxfamily org.
  • To unsubscribe, send a mail with subject "unsubscribe" to eigen-request at lists tuxfamily org.

Once you are subscribed, you may post to eigen at lists tuxfamily org.

You can also browse the archive

You can also contact us by IRC : #eigen on irc.freenode.net.