mju_factorLU6/mju_solveLU6: same algorithm as mju_factorLU/mju_solveLU
with compile-time size, allowing full unrolling. At n=6, factor+solve is
25% faster than the runtime-sized version (93 vs 124 ns), and fixed-size
LU factorization is faster than generic dense Cholesky (55 vs 61 ns):
at this size, runtime-n loop overhead outweighs Cholesky's 2x flop
advantage. See new lu_benchmark_test. Results agree with the generic
version to rounding, not bitwise: the compiler may fuse (FMA) the
unrolled version differently.
Also add two DenseLU tests: a pivoting-required matrix with zero
diagonal, and fixed-vs-generic agreement.
PiperOrigin-RevId: 947705056
Change-Id: I24c54c9510964aa376886e9dd721890eda9889d3
This is a no-op "prefactor" of `mj_crb` to reduce the number of lines changed in the upcoming sleeping CL. The main change here is that `mj_crb` now avoids accessing the model and data pointer repeatedly, but instead has the input and output pointers explicitly declared as local variables. A benchmark test found a healthy **14% perf bump** due to two changes:
- Adding `restrict` to `mju_mulInertVec`
- The function-local pointers.
Adding `restrict` to the local pointers had no effect. Note that `mj_crb` is not a particularly expensive function so these speed bumps are not significant per se, but rather indicative of possible future gains with these techniques.
```
Benchmark Time(ns) CPU(ns) Iterations
---------------------------------------------------------------
ORGINAL BASELINE
BM_CRB_BASELINE_mean 4325 4348 993200 230.052k items/s
BASELINE + RESTRICT
BM_CRB_BASELINE_mean 4057 4090 1186150 244.573k items/s
LOCAL POINTERS + RESTRICT
BM_CRB_mean 3772 3800 1001750 263.209k items/s
```
PiperOrigin-RevId: 815798225
Change-Id: Iffdf57b544e8e10562807c617f73ca4ccd1c614f
All instances of mujoco_test in the code base were followed by
a call to target_link_libraries(<testname> fixture gmock).
As anyhow mujoco_test already was calling target_link_libraries
to some predefined list of targets (mujoco and gtest_main),
this PR adds to the list of default linked targets also fixture
and gmock, to reduce the boilerplate.
Furthermore, to completly remove the need for calling
target_link_libraries after a call to mujoco_test, this PR also
add to the mujoco_test macro the ADDITIONAL_LINK_LIBRARIES
argument, that can be used if a given test needs to link some
additional targets beside the default ones.
To permit to use these new features also for mujoco benchmarks,
this PR adds a MAIN_TARGET parameter to mujoco_test, to select
if gtest_main or another target is used to provide the main
entry point to the test executable.
Yuval Tassa