Alessio Quaglino
f9f1db1e0a
with a preconditioned Conjugate Gradient (CG) solver that operates on the full system matrix. The previous approach extracted flex DOFs into a reduced banded system, factored it separately, and overwrote the global solve. This required precomputed bandwidth (makeFlexBandwidth), parent-joint detection, coupling corrections, and a FlexInterpContext struct — and only worked for standalone flex trees without parent joints. The new CG solver uses the already-factored global system (M - h*qDeriv) as a preconditioner and adds the flex stiffness contribution via matrix-free products (mjd_flexInterp_mulKD/mulK). This handles any kinematic configuration — including flexes attached to articulated chains or with parent joints — without sparsity pattern restrictions. Before (`bunny_multicell`): ``` Simulation time : 50.80 s Steps per second : 197 Realtime factor : 0.20 x Time per step : 5080.3 µs CG iters / step : 3.16 Contacts / step : 31.04 Constraints / step : 124.15 Degrees of freedom : 178 Dynamic memory usage : 0.4% of 100M ``` After: ``` Simulation time : 9.52 s Steps per second : 1051 Realtime factor : 1.05 x Time per step : 951.7 µs CG iters / step : 3.21 Contacts / step : 30.90 Constraints / step : 123.61 Degrees of freedom : 178 Dynamic memory usage : 0.3% of 100M ``` PiperOrigin-RevId: 913758038 Change-Id: If5aa617b2d535c86aec9bd71c9e0003a2b38bdd7
MuJoCo Python Bindings
This package is the canonical Python bindings for the MuJoCo physics engine. These bindings are developed and maintained by Google DeepMind, and is kept up-to-date with the latest developments in MuJoCo itself.
The mujoco package provides direct access to raw MuJoCo C API functions,
structs, constants, and enumerations. Structs are provided as Python classes,
with Pythonic initialization and deletion semantics.
It is not the aim of this package to provide fully fledged
scene/environment/game authoring API, as there are already a number of existing
packages that do this well. However, this package does provide a number of
lower-level components outside of MuJoCo itself that are likely to be useful to
most users who access MuJoCo through Python. For example, the egl, glfw, and
osmesa subpackages contain utilities for setting up OpenGL rendering contexts.
Installation
The recommended way to install this package is via PyPI:
pip install mujoco
A copy of the MuJoCo library is provided as part of the package and does not need to be downloaded or installed separately.
Source
IMPORTANT: Building from source is only necessary if you are modifying the Python bindings (or are trying to run on exceptionally old Linux systems). If that's not the case, then we recommend installing the prebuilt binaries from PyPI.
If you need to build the Python bindings from source, please consult the documentation.
Usage
Once installed, the package can be imported via import mujoco. Please consult
our documentation for
further detail on the package's API.
We recommend going through the tutorial notebook which covers the basics of
MuJoCo using Python:
Versioning
The major.minor.micro portion of the version number matches the version of
MuJoCo that the bindings provide. Optionally, if we release updates to the
Python bindings themselves that target the same version of MuJoCo, a .postN
suffix is added, for example 2.1.2.post2 represents the second update to the
bindings for MuJoCo 2.1.2.
License and Disclaimer
Copyright 2022 DeepMind Technologies Limited
MuJoCo and its Python bindings are licensed under the Apache License, Version 2.0. You may obtain a copy of the License at https://www.apache.org/licenses/LICENSE-2.0.
This is not an officially supported Google product.