Graphite

Graphite is a GPU-accelerated nonlinear least squares graph optimization framework based on CUDA. It lets you define an optimization problem in terms of unary, binary, and n-ary constraints (e.g. pose graph optimization, bundle adjustment), using data structures defined in C++, which may be useful for applications in robotics and computer vision such as SLAM. Graphite also supports configurable floating point precisions as well as mixed-precision solving.

⚠️ Graphite is experimental. There may be several bugs, performance issues, and limitations. The interface and implementation may change over time.

For more details, refer to the paper.

Supported linear solvers:

• Preconditioned Conjugate Gradients
• Eigen LDLT
• cuDSS

Supported algorithms:

• Levenberg-Marquardt

Building

You need a recent version of the CUDA Toolkit (e.g. >= 12.0), Eigen3, and cuDSS 0.7.0. Graphite can be built using CMake. A Dockerfile for development is also included, which can be used to create a devcontainer for VS Code (requires the NVIDIA Container Toolkit).

You can build Graphite and its examples using the following commands:

git clone https://github.com/sfu-rsl/graphite.git
cmake -DCMAKE_BUILD_TYPE=Release graphite -B build
cmake --build build

To instead use Graphite as a library inside an existing CMake project, you can add it as a dependency using the add_subdirectory(...) command in your CMakeLists.txt file. You can then link graphite to your build target.

You may also have to adjust the following settings near the top, before adding the subdirectory:

project(YourProject LANGUAGES CUDA CXX)
set(CMAKE_CUDA_FLAGS "${CMAKE_CUDA_FLAGS} --expt-relaxed-constexpr --extended-lambda --default-stream per-thread")
set(CMAKE_CUDA_ARCHITECTURES 86) # You need to actually look up the correct CC number for your GPU

Graphite code should be called inside a .cu file to avoid compile errors.

Examples

See the examples folder. There are two examples:

• circle.cu - Optimizes noisy 2D points along the radius of a circle
• bal.cu - Performs bundle adjustment

License

Graphite is released under the MIT License.

Contributing

If you would like to contribute features, bug fixes, code improvements, or tests, please open an issue or discussion first. Questions about usage are better suited for discussion.