## GTSAM 2.3.0 Release

We are pleased to announce GTSAM 2.3.0! Notable changes from 2.2.0 include:

- Added a basic IMU (inertial navigation) factor for estimating 6-dof pose, translational velocity, and IMU/gyro bias (supports both time-varying and constant bias).
- Added an "equivalent summarized" IMU factor with the same capabilities as the basic one, but that precomputes a summary of a large number of IMU measurements to allow for efficient relinearization (following Lupton and Sukkarieh in TRO 2012). Currently uses numerical derivatives, but an update to be released shortly as part of GTSAM 2.3.1 will use analytic derivatives for improved computational efficiency.
- New feature - basic "summarization" of nonlinear systems - Given an existing nonlinear graph and a linearization point, summarization creates a new nonlinear system on a specified subset of variables in the graph. The summarization is obtained by marginalizing out other variables in the linearized system. This new summarized graph can be added back into a nonlinear graph under a linearization assumption.
- Major speed improvements in iSAM2 when dealing with many, >50,000, variables (e.g. very long chains).
- Several build system improvements (see detailed changelist)

**Information and Download****Detailed Changelist**

We welcome your feedback and questions at gtsam@lists.gatech.edu.