# ilqgames

**Repository Path**: qiu555/ilqgames

## Basic Information

- **Project Name**: ilqgames
- **Description**: No description available
- **Primary Language**: Unknown
- **License**: BSD-3-Clause
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 0
- **Created**: 2026-05-01
- **Last Updated**: 2026-05-01

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

# *ilqgames*
![Build Status](https://travis-ci.org/HJReachability/ilqgames.svg?branch=master) ![License](https://img.shields.io/badge/license-BSD-blue.svg)

Iterative Linear-Quadratic Games - a new, real-time solver for _N_-player general differential games.

*NOTE* that this project is still under active development and is only intended to be used as an academic reference at this stage. However, my intent is that it should eventually become stable enough for use as a reliable substitute for a model-predictive control backend.

## Paper
For a full description of the algorithm itself and examples of how it can be applied in collision-avoidance problems, please refer to the [paper](https://arxiv.org/abs/1909.04694), which was presented at ICRA 2020.

If you find this repository useful, please do cite the paper:
```
@inproceedings{fridovich2020efficient,
  title={Efficient iterative linear-quadratic approximations for nonlinear multi-player general-sum differential games},
  author={Fridovich-Keil, David and Ratner, Ellis and Peters, Lasse and Dragan, Anca D and Tomlin, Claire J},
  booktitle={2020 IEEE International Conference on Robotics and Automation (ICRA)},
  pages={1475--1481},
  year={2020},
  organization={IEEE}
}
```
If you are interested in the feedback linearized version of this algorithm, please also refer to that [paper](https://arxiv.org/abs/1910.00681), which is also published at ICRA 2020:
```
@inproceedings{fridovich2020iterative,
  title={An iterative quadratic method for general-sum differential games with feedback linearizable dynamics},
  author={Fridovich-Keil, David and Rubies-Royo, Vicenc and Tomlin, Claire J},
  booktitle={2020 IEEE International Conference on Robotics and Automation (ICRA)},
  pages={2216--2222},
  year={2020},
  organization={IEEE}
}
```

## Primary contributor
The primary contributor is [David Fridovich-Keil](https://dfridovi.github.io), a recent PhD grad from Claire Tomlin's group in the EECS department at UC Berkeley. David is currently an assistant professor at UT Austin. The best way to contact David is by email, _dfk at utexas dot edu_, or if you have specific questions about this repository, please post an [issue](https://github.com/HJReachability/ilqgames/issues).

## Documentation
Documentation is automatically generated by a continuous integration service with each push to the `master` branch, and it may be found [here](https://HJReachability.github.io/ilqgames/documentation/html/). Additionally, a more high-level form of documentation is available in PDF form [here](https://github.com/HJReachability/ilqgames/blob/master/ILQGames_Documentation.pdf).

## Language
An early version of the iterative linear-quadratic game algorithm was implemented in Python; it is now deprecated and stored in the `python/` directory. Ongoing and future development will proceed primarily in C++, although a colleague has built a standalone version in Julia [here](https://github.com/lassepe/iLQGames.jl)

## Dependencies
*ilqgames* has been tested both in OS X and Ubuntu. Depending on your version of Ubuntu, you may notice a linker error related to `aclocal-XX`, which may be fixed by symlinking Ubuntu's native `aclocal` to the desired executable `aclocal-XX`. Otherwise, external dependencies are standard:

* `glog` (Google's logging tools)
* `gflags` (Google's command line flag tools)
* `opengl`, `glut` (graphics tools)
* `eigen3` (linear algebra library)

## Getting started
This repository uses the `cmake` build system and may be compiled following standard cmake protocols:
```
mkdir build && cd build
cmake ..
make -j8
```

Executables will be stored in the `bin/` directory, with the exception of `build/run_tests`, which runs unit tests. To run unit tests from the build directory, simply execute:
```
./run_tests
```

To run a particular example from the `bin/` directory, e.g., the three-player intersection:
```
./three_player_intersection
```

With any executable, a full explanation of command line arguments can be found by running:
```
./<name-of-executable> --help
```

## Extending *ilqgames*
### New examples
All specific examples, e.g. the three-player intersection, inherit from the base class `Problem`. This base class provides a number of utilities, such as warm starting, and also wraps the solver. To inherit, simply write a constructor which instantiates the appropriate solver with costs, and also set the initial state, operating point, and strategies. To see an example, consult the [ThreePlayerIntersectionExample](https://github.com/HJReachability/ilqgames/blob/master/src/three_player_intersection_example.cpp) class.

### ROS
There is a companion ROS extension under development, which may be found [here](https://github.com/HJReachability/ilqgames_ros). It is currently still marked private, but rest assured that the usage of the *ilqgames* toolbox in ROS is straightforward! If you want to implement this yourself for a custom application it is not too hard.

### GUI
The native *ilqgames* graphical user interface can be a very useful tool in debugging algorithm changes, new costs, etc. Currently, it supports so-called `TopDownRenderableProblem` games, where the state encodes x-y position and (potentially) heading information. To extend the GUI to other types of games, simply write a custom renderer, e.g. mirroring the `TopDownRenderer` class. All GUI functionality is based on the [DearImGui](https://github.com/ocornut/imgui) library, a copy of which is maintained locally in the `external/` directory.