MuJoCo Warp (MJWarp)

MJWarp is a GPU-optimized version of the MuJoCo physics simulator, designed for NVIDIA hardware.

Warning

MJWarp is in its Alpha stage, with many features still missing and limited testing so far.

MJWarp uses NVIDIA Warp to circumvent many of the sharp bits in MuJoCo MJX. Once MJWarp exits Alpha, it will be integrated into both MJX and Newton.

MJWarp is maintained by Google DeepMind and NVIDIA.

Installing for development

git clone https://github.com/google-deepmind/mujoco_warp.git
cd mujoco_warp
python3 -m venv env
source env/bin/activate
pip install --upgrade pip

During early development, MJWarp is on the bleeding edge - you should install Warp nightly:

pip install warp-lang --pre --upgrade -f https://pypi.nvidia.com/warp-lang/

Then install MJWarp in editable mode for local development:

pip install -e .[dev,cuda]

Now make sure everything is working:

pytest

Should print out something like XX passed in XX.XXs at the end!

If you plan to write Warp kernels for MJWarp, please use the kernel_analyzer vscode plugin located in contrib/kernel_analyzer. Please see the README.md there for details on how to install it and use it. The same kernel analyzer will be run on any PR you open, so it's important to fix any issues it reports.

Compatibility

The following features are implemented:

Category	Feature
Dynamics	Forward only
Transmission	JOINT, JOINTINPARENT, TENDON
Actuator Dynamics	NONE, INTEGRATOR, FILTER, FILTEREXACT, MUSCLE
Actuator Gain	FIXED, AFFINE, MUSCLE
Actuator Bias	NONE, AFFINE, MUSCLE
Geom	PLANE, SPHERE, CAPSULE, ELLIPSOID, CYLINDER, BOX, MESH
Constraint	FRICTION JOINT, FRICTION TENDON, LIMIT_BALL, LIMIT_JOINT, LIMIT_TENDON,
	CONTACT_PYRAMIDAL, CONTACT_ELLIPTIC
Equality	CONNECT, WELD, JOINT, TENDON
Integrator	EULER, IMPLICITFAST, RK4
Cone	PYRAMIDAL, ELLIPTIC
Condim	1, 3, 4, 6
Solver	CG, NEWTON
Fluid Model	BOX
Tendons	FIXED, SITE
Sensors	CAMPROJECTION, JOINTPOS, TENDONPOS, ACTUATORPOS, BALLQUAT, FRAMEPOS, FRAMEXAXIS,
	FRAMEYAXIS, FRAMEZAXIS, FRAMEQUAT, SUBTREECOM, CLOCK, VELOCIMETER, GYRO, JOINTVEL,
	TENDONVEL, ACTUATORVEL, BALLANGVEL, FRAMELINVEL, FRAMEANGVEL, SUBTREELINVEL, SUBTREEANGMOM,
	TOUCH, ACCELEROMETER, FORCE, TORQUE, ACTUATORFRC, JOINTACTFRC,FRAMELINACC, FRAMEANGACC

Benchmarking

Benchmark as follows:

mjwarp-testspeed --function=step --mjcf=test_data/humanoid/humanoid.xml --batch_size=8192

To get a full trace of the physics steps (e.g. timings of the subcomponents) run the following:

mjwarp-testspeed --function=step --mjcf=test_data/humanoid/humanoid.xml --batch_size=8192 --event_trace=True