* Move units into API docs instead because suffixes make user code verbose and hard to read
* Rename trackWidth to trackwidth
* Make ultrasonic classes use meters instead of a mix of m, cm, mm, ft,
and inches
Small values of kₐ make the iterative solver ill-conditioned. This
change reverts to the constant-acceleration feedforward in that case. It
gives _very_ bad results (hence why we added the iterative solver in the
first place), but it's better than hanging.
```
TEST(ArmFeedforwardTest, CalculateIllConditioned) {
constexpr auto Ks = 0.5_V;
constexpr auto Kv = 20_V / 1_rad_per_s;
constexpr auto Ka = 1e-2_V / 1_rad_per_s_sq;
constexpr auto Kg = 0_V;
frc::ArmFeedforward armFF{Ks, Kg, Kv, Ka};
// Calculate(currentAngle, currentVelocity, nextAngle, dt)
CalculateAndSimulate(armFF, 0_rad, 0_rad_per_s, 2_rad_per_s, 20_ms);
}
```
This produces 1 V and doesn't accelerate the system at all. Using
nextVelocity instead of currentVelocity in the feedforward outputs 41 V
and still only accelerates to 0.4 rad/s of the requested 2 rad/s.
I picked the kₐ cutoff by increasing kₐ until the iterative solver
started converging.
Fixes#7743.
It now uses SQP for problems without inequality constraints, which is
faster.
main:
```
[ RUN ] Ellipse2dTest.DistanceToPoint
0.203 ms
[ OK ] Ellipse2dTest.DistanceToPoint (0 ms)
[ RUN ] Ellipse2dTest.FindNearestPoint
0.019 ms
[ OK ] Ellipse2dTest.FindNearestPoint (0 ms)
```
upgrade:
```
[ RUN ] Ellipse2dTest.DistanceToPoint
0.197 ms
[ OK ] Ellipse2dTest.DistanceToPoint (0 ms)
[ RUN ] Ellipse2dTest.FindNearestPoint
0.015 ms
[ OK ] Ellipse2dTest.FindNearestPoint (0 ms)
```
This is easier to type and follows the naming of Pose2d::Nearest().
Since Ellipse2d and Rectangle2d were added for the 2025 season, we don't
need to add deprecation notices.
The Raspberry Pi 5 is fast enough that we no longer need it.
```
Running ./build/DAREBench
Run on (4 X 2400 MHz CPU s)
CPU Caches:
L1 Data 64 KiB (x4)
L1 Instruction 64 KiB (x4)
L2 Unified 512 KiB (x4)
L3 Unified 2048 KiB (x1)
Load Average: 0.47, 0.72, 0.45
***WARNING*** CPU scaling is enabled, the benchmark real time measurements may be noisy and will incur extra overhead.
-------------------------------------------------------------------------------
Benchmark Time CPU Iterations
-------------------------------------------------------------------------------
DARE_WPIMath_Dynamic 34.4 us 34.4 us 20315
DARE_WPIMath_NoPrecondChecks_Dynamic 21.7 us 21.7 us 32266
DARE_WPIMath_Static 15.2 us 15.2 us 45878
DARE_WPIMath_NoPrecondChecks_Static 7.84 us 7.84 us 89316
DARE_SLICOT 79.4 us 79.4 us 8789
DARE_Drake 34.9 us 34.9 us 20074
```
