The derivatives of actuator velocity with respect to generalized velocities were incorrectly computed when the actuator force was limited by `forcerange`. This CL adds a check to zero out these derivatives when the actuator force is at its upper or lower limit, as the force is no longer a function of velocity in this clamped state.
PiperOrigin-RevId: 868818281
Change-Id: I89742a3f04989dd11f9cfada107200015b1472a7
Replace dynamically-sized edge list with a dense ntree×ntree adjacency matrix for deduplication and a flat CSR representation.
PiperOrigin-RevId: 868728432
Change-Id: Iebe97a0870740e5465549b967bbde0c81e658269
The derivative calculation for actuator velocity in implicit integrators now correctly accounts for the `actearly` flag, using the next activation value when `actearly` is true.
PiperOrigin-RevId: 868598722
Change-Id: Ia180afb15b31a718170aeaf9d4ac514bb9e6073b
The implicit integrator was not correctly accounting for the off-diagonal coupling terms between flex and non-flex (parent) degrees of freedom in the mass matrix. This change extracts these coupling terms during the factorization step and applies a correction to the flex forces before solving for the flex accelerations, ensuring that the parent accelerations influence the flex dynamics. A new test verifies that the implicit integrator now matches Euler for small timesteps in a model with flex-parent coupling.
PiperOrigin-RevId: 868098126
Change-Id: Ia8cccd7dd428cd0c0898e1663a7e41017a2311b2
The functions and associated tests related to managing time-stamped data buffers have been renamed from `mju_delay*` to `mju_history*` to better reflect their general purpose beyond just handling delays.
PiperOrigin-RevId: 866978339
Change-Id: I8655e91bce783287ad2adc412d13a1c39aa2c322
The new symbolic function is a generalization of the function it replaces. In this CL it takes two unused temp arrays. The actual change in behavior happens in the followup.
New benchmark test output below ("L" is 2 humanoids and 100 free objects, "XL" is 100 humanoids). Note that `symbolic` is only ever called once per Newton iteration, while `numeric` is sometimes called multiple times (when the rank-1 update fails), hence timing them separately is valuable.
```
Benchmark Time(ns) CPU(ns) Iterations
--------------------------------------------------------------
BM_old_L_mean 84382 84703 19547 11.807k items/s
BM_symbolic_L_mean 16345 16381 88414 61.055k items/s
BM_numeric_L_mean 10986 10994 120000 90.999k items/s
BM_old_XL_mean 1241208 1244212 1200 803.924 items/s
BM_symbolic_XL_mean 130917 131042 12720 7.631k items/s
BM_numeric_XL_mean 77004 76767 21116 13.029k items/s
```
PiperOrigin-RevId: 846704054
Change-Id: Ib0c365724d63bf2b81606ca5353756a6496c3a26
This function allows the caller to extract a subset of components of a state previously obtained via `mj_getState` without having to first write it back into `mjData`.
PiperOrigin-RevId: 822165077
Change-Id: I6433261f4f5ec2e8d024bb7dee8f7dbf1e62666c
This is strictly an out array and should not be read before it is written to. This change improves MSAN coverage of engine code.
PiperOrigin-RevId: 819767673
Change-Id: I57500c8147f4774d326cf87ea3bac5420e4dd54d
Taylor Howell