As of August 1 2020, the `develop` branch is officially in "Pre 4.1" mode, and features deprecated in 4.0 have been removed. Please use the last [4.0.3 release](https://github.com/borglab/gtsam/releases/tag/4.0.3) if you need those features.
However, most are easily converted and can be tracked down (in 4.0.3) by disabling the cmake flag `GTSAM_ALLOW_DEPRECATED_SINCE_V4`.
- [Intel Math Kernel Library (MKL)](http://software.intel.com/en-us/intel-mkl) (Ubuntu: [installing using APT](https://software.intel.com/en-us/articles/installing-intel-free-libs-and-python-apt-repo))
GTSAM 4 introduces several new features, most notably Expressions and a Python toolbox. It also introduces traits, a C++ technique that allows optimizing with non-GTSAM types. That opens the door to retiring geometric types such as Point2 and Point3 to pure Eigen types, which we also do. A significant change which will not trigger a compile error is that zero-initializing of Point2 and Point3 is deprecated, so please be aware that this might render functions using their default constructor incorrect.
GTSAM 4 also deprecated some legacy functionality and wrongly named methods. If you are on a 4.0.X release, you can define the flag GTSAM_ALLOW_DEPRECATED_SINCE_V4 to use the deprecated methods.
GTSAM 4.1 added a new pybind wrapper, and **removed** the deprecated functionality. There is a flag GTSAM_ALLOW_DEPRECATED_SINCE_V41 for newly deprecated methods since the 4.1 release, which is on by default, allowing anyone to just pull version 4.1 and compile.
We provide support for [MATLAB](matlab/README.md) and [Python](cython/README.md) wrappers for GTSAM. Please refer to the linked documents for more details.
- Todd Lupton and Salah Sukkarieh, "Visual-Inertial-Aided Navigation for High-Dynamic Motion in Built Environments Without Initial Conditions", TRO, 28(1):61-76, 2012. [[link]](https://ieeexplore.ieee.org/document/6092505)
- Luca Carlone, Zsolt Kira, Chris Beall, Vadim Indelman, and Frank Dellaert, "Eliminating conditionally independent sets in factor graphs: a unifying perspective based on smart factors", Int. Conf. on Robotics and Automation (ICRA), 2014. [[link]](https://ieeexplore.ieee.org/abstract/document/6907483)
- Christian Forster, Luca Carlone, Frank Dellaert, and Davide Scaramuzza, "IMU Preintegration on Manifold for Efficient Visual-Inertial Maximum-a-Posteriori Estimation", Robotics: Science and Systems (RSS), 2015. [[link]](http://www.roboticsproceedings.org/rss11/p06.pdf)
In GTSAM 4 a new and more efficient implementation, based on integrating on the NavState tangent space and detailed in [this document](doc/ImuFactor.pdf), is enabled by default. To switch to the RSS 2015 version, set the flag **GTSAM_TANGENT_PREINTEGRATION** to OFF.
GTSAM was developed in the lab of [Frank Dellaert](http://www.cc.gatech.edu/~dellaert) at the [Georgia Institute of Technology](http://www.gatech.edu), with the help of many contributors over the years, see [THANKS](THANKS.md).
