Per-parameter scaling via change of variables z = x / D. Supports
'jac' (adaptive D_i = 1/||J(:,i)|| per iteration, matches scipy's TRF),
explicit array, or a positive scalar. Default 1.0 is a no-op.
For example, `compile mujoco_menagerie/robotis_op3/scene.xml` now outputs
```
Compile 1 (cold cache):
total: 317.2 ms
assets: 284.8 ms (wall clock)
load: 616.1 ms
hull: 26.4 ms
poly: 137.8 ms
inert: 177.8 ms
bvh: 568.2 ms
octr: 1.6 ms
tex: 25.3 ms
other: 32.4 ms
Compile 2 (warm cache):
total: 79.9 ms
assets: 54.5 ms (wall clock)
load: 888.5 ms
hull: 0.0 ms
poly: 0.0 ms
inert: 0.0 ms
bvh: 0.0 ms
octr: 0.0 ms
tex: 21.4 ms
other: 25.3 ms
```
PiperOrigin-RevId: 917850214
Change-Id: Iaec86230bec0faf2e47820e20cbff61de5b2621e
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
The maximum depth of the octree used for SDF generation can now be specified in the mesh definition via `mjsMesh::octree_maxdepth`. The default value is 6.
PiperOrigin-RevId: 912494999
Change-Id: I6d828d1d3999b99d1210a6829a05b04fac591e1f
The new function mjs_getOriginSpec returns the mjSpec that was used to define a given mjsElement. Unlike mjs_getSpec, this value remains constant even after the element has been attached to a different model.
PiperOrigin-RevId: 911930951
Change-Id: Ia9cd79d9dfabc513d6121eadcffc5d41075224c9
This change introduces MjVFS, an explicit object to mirror the C mjVFS. This is meant to replace the MjSpec.assets dict. This latter while convenient guides users towards harmful authoring patterns with respect to data duplication and spec attachment workflows. Making VFS management explicit should encourage better memory usage and allow us to make better compile time optimizations.
From this change, `spec.assets` is deprecated. However we will temporarily support backwards compatibility due to the wide spread usage. An error will be thrown if calling code tries to use a spec that uses both the assets dict and the new MjVfs.
PiperOrigin-RevId: 908772050
Change-Id: I77c6d0369307fc300c954768fed17401261e18da
The flex interpolation stiffness matrix within the implicit/implicitfast solvers is now built and factorized in a banded format instead of a dense one. This involves:
- Calculating the bandwidth based on the sparsity of the mass/damping matrix and the connectivity within flex cells.
- Allocating and populating a banded matrix `H`.
- Using `mju_cholFactorBand` and `mju_cholSolveBand` for factorization and solving.
This change improves performance for flexes with many DOFs but local coupling.
PiperOrigin-RevId: 901297952
Change-Id: I3efe06353d1903ea65ab30dc49685cede228bb68
This change introduces a `flex_cellcount` field to `mjModel` to specify the number of cells in each dimension for interpolated flexes. The stiffness computation, passive force calculation, and Jacobian derivatives are updated to operate on a per-cell basis, significantly improving performance by localizing computations to the nodes within each cell.
PiperOrigin-RevId: 901216393
Change-Id: Ic23132e609de11e71bb7fef8d1f139daad2ec264
If Renderer.__init__ raises before the rendering contexts are assigned
(e.g. width > offwidth raises ValueError, or MjrContext construction
fails), __del__ calls close() which accesses self._gl_context and
self._mjr_context unconditionally, raising AttributeError. This masks
the real __init__ failure with a noisy "Exception ignored in..." message
during garbage collection.
Pre-initialize both attributes to None at the top of __init__ so that
close() is safe on a partially-constructed instance. Add a regression
test that captures sys.unraisablehook and asserts that __del__ raises
nothing when __init__ fails via the width > offwidth path.
Fixes#3213.
This change introduces `nflexstiffness` and `flex_stiffnessadr` to allow flex stiffness matrices to have sizes other than the fixed 21 per element. Higher-order flexes can now store larger stiffness matrices based on their number of nodes. The `flex_stiffnessadr` array provides the starting index for each flex's stiffness data within the `flex_stiffness` array.
PiperOrigin-RevId: 899632263
Change-Id: Ie49182c46c3777acf0c6b492345edfcf62fb5e44
This change disallows calling `mjs_delete` on an mjSpec that has been attached to another mjSpec via `mjs_attach`. Attempting to delete an element from an attached spec will now result in an error. The Python bindings for `mjSpec.delete` have been updated to raise a ValueError when this occurs.
PiperOrigin-RevId: 897266695
Change-Id: Ic0670125a3028191ec50eca890f02b5910ec8b03
- Remove `lugre:viscous`, should now be added directly to actuator `damping`. Trying to do this for the user was incompatible with default inheritance (compounding instead of overriding).
- Move voltage limiting from the `saturation` to the `controller` attribute.
- Fix indexing issues in default inheritance.
PiperOrigin-RevId: 897087642
Change-Id: I5388c2633e15c7e223992e7eb5d6a28db75a6438
Add a new mjpEncoder plugin type mirroring the existing mjpDecoder pattern.
Encoders serialize an mjSpec + mjModel to an mjResource for a given format.
New API functions:
- mjp_registerEncoder: globally register an encoder
- mjp_defaultEncoder: zero-initialize an encoder struct
- mjp_findEncoder: look up an encoder by filename extension or content type
The mjfEncode callback takes (mjSpec*, mjModel*, mjVFS*, mjResource*) and
returns 0 on success. Writing to mjResource keeps symmetry with the decoder
reading from mjResource and leaves the door open for writable resource providers.
PiperOrigin-RevId: 889187898
Change-Id: I180771b2255b91dea188ac5e2cdc3a8f0fb85364
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