Obsidian is a system for computing probabilistic geophysical inversions from a variety of sensor types. It is written primarily in C++ and runs on GNU/Linux and Unix operating systems.

The installation guide has instructions on how to install Obsidian and its prerequisites. The quick start page offers a good insight into the basic workflow of using Obsidian to perform an inversion. A brief description of the different modules of Obsidian can be found in the Modules page. The main code API reference is also available here.