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− | The Eigen project was started by Benoît Jacob (founder) and Gaël Guennebaud (guru). Many other people have since contributed their talents to help make Eigen successful. | + | The Eigen project was started by Benoît Jacob (founder) and Gaël Guennebaud (guru). Many other people have since contributed their talents to help make Eigen successful. In alphabetical order: |
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Revision as of 17:56, 11 December 2009
Date: November 25, 2009
Eigen 3.0 plans announced.
Even the first beta of Eigen 3.0 is still far away. It is not yet time to port your code to it.
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.
- various numeric types out of the box, including std::complex numbers, while being easy to extend to custom numeric types.
- 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. This is for the stable version.
It includes a Tutorial.
Here is the documentation of the unstable development branch.
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 dependencies other than the C++ standard library.
We use the CMake build system, but 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, and no configured header file. Eigen is a pure template library defined in the headers.
Download
The latest stable release is Eigen 2.0.10. Get it here: tar.bz2, tar.gz, zip.
More generally, if you want release x.y.z in, say, tar.bz2 format, just use the URL
http://bitbucket.org/eigen/eigen/get/x.y.z.tar.bz2
These archives are automatically generated and so all combinations are possible -- also for beta and RC releases. See this page for some possibilities.
Here is the unstable source archive of the development branch: tar.bz2, tar.gz, zip.
Here is the source archive of the 2.0 branch: tar.bz2, tar.gz, zip.
You can also browse the source code.
The SCM tool used for Eigen development is Mercurial also known as "Hg".
To check out the Eigen repository, do:
hg clone https://bitbucket.org/eigen/eigen/
After you have run this command, you have a eigen/ directory defaulting to the development branch (heading toward the next major version, 3.0).
If instead you want the 2.0 branch, enter the eigen/ directory and do:
hg up 2.0
If instead you want the 2.0.10 tag, enter the eigen/ directory and do:
hg up 2.0.10
For more information about using Mercurial with Eigen, see this page.
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.
Compiler support
Eigen is standard C++98 and so should theoretically be compatible with any compliant compiler. Whenever we use some non-standard feature, that is optional and can be disabled.
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, which also gives good performance.
- 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 the latest gcc (currently 4.4)
- The Sun compiler
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
- The Space Trajectory Analysis project at the European Space Agency. They even have an announcement on using Eigen.
- Avogadro, an opensource advanced molecular editor.
- The 3D astronomical visualization application Celestia is now using Eigen for all orbital and geometric calculation.
Robotics and engineering
- The Yujin Robot company uses Eigen for the navigation and arm control of their next gen robots. (switched from blitz, ublas and tvmet)
- The Robotic Operating System (ROS) developed by Willow Garage.
- openAHRS Open Source IMU / AHRS
- The Darmstadt Dribblers autonomous Humanoid Robot Soccer Team and Darmstadt Rescue Robot Team use Eigen for navigation and world modeling.
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!)
- Gluon, a high-level KDE game development library.
- Step, an educational physics simulator.
- 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.
- the Mandelbrot wallpaper plugin, some screensavers, kgllib, solidkreator, etc.
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? Use our mailing list.
Bug reports
For bug reports and feature requests, please use the issue tracker.
Mailing list
Our mailing list is the central point for discussion of Eigen development.
- 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.
Important: After you sent your subscription request, you will receive a confirmation e-mail. Check your spam folder, as these confirmation e-mails are often filtered as spam!
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.
Credits
The Eigen project was started by Benoît Jacob (founder) and Gaël Guennebaud (guru). Many other people have since contributed their talents to help make Eigen successful. In alphabetical order:
David Benjamin | Artwork: the owls |
Armin Berres | Lots of fixes (compilation warnings and errors) |
Mark Borgerding | FFT module |
Thomas Capricelli | Migration to mercurial, Non-linear optimization and numerical differentiation, cron-job to update the online dox |
Andrew Coles | Fixes (including a compilation error) |
Christian Ehrlicher | MSVC compilation fix |
Daniel Gomez Ferro | Improvements in Sparse and in matrix product |
Rohit Garg | Vectorized quaternion and cross products, improved integer product |
Mathieu Gautier | QuaternionMap and related improvements |
Gaël Guennebaud | Core developer |
Marcus D. Hanwell | CMake improvements. Marcus is a developer at Kitware! |
Hauke Heibel | Lots of increasingly 'core' things |
Benoît Jacob | Core developer |
Marijn Kruisselbrink | CMake fixes |
Moritz Lenz | Allow solving transposed problem with SuperLU |
Konstantinos A. Margaritis | AltiVec vectorization |
Ricard Marxer | Reverse, redux improvements, the count() method, some dox |
Vincenzo Di Massa | CMake fix |
Christian Mayer | Early code review and input in technical/design discussions |
Frank Meier-Dörnberg | MSVC compatibility fixes |
Keir Mierle | LDLT decomposition and other improvements |
Laurent Montel | CMake improvements. Laurent is (with Alexander) one of the CMake gurus at KDE! |
Alexander Neundorf | CMake improvements. Alexander is (with Laurent) one of the CMake gurus at KDE! |
Jitse Niesen | Matrix exponential, improved tutorial |
Jos van den Oever | Compilation fix |
Michael Olbrich | Early patches, including the initial loop meta-unroller. |
Stjepan Rajko | MSVC compatibility fix |
Jure Repinc | CMake fixes |
Kenneth Frank Riddile | Lots of Windows/MSVC compatibility fixes |
Peter Román | support for SuperLU's ILU factorization |
Guillaume Saupin | Skyline matrices |
Benjamin Schindler | gdb pretty printers |
Alex Stapleton | Help with tough C++ questions |
Anthony Truchet | Bugfix in QTransform and QMatrix support |
James Richard Tyrer | CMake fix |
Rhys Ulerich | Pkg-config support |
Ingmar Vanhassel | CMake fix |
Scott Wheeler | Documentation improvements |
Urs Wolfer | Fixed a serious warning |
Manuel Yguel | Bug fixes and work on inverse-with-check |
Special thanks to Tuxfamily for the wonderful quality of their services!