`sim`¶

org.horizon36596.simloop.sim

The clock, the loop, and getting a log back out again.

What you use¶

Type	What it is
`FakeTimer`	The deterministic clock. Advances only when a tick advances it.
`ScenarioRunner`	Runs a whole scenario: owns the fixed-timestep loop and the entire PsiKit logging lifecycle.
`RlogDecodedCompare`	Decodes an RLOG back into per-frame field maps, and compares two runs field by field.

Running a scenario¶

ScenarioRunner.run(
        "SlideExample",        // OpMode name, recorded in the log's metadata
        robotConfig,           // your SimRobotConfig
        timer,                 // the FakeTimer, constructed and wired BEFORE this call
        150,                   // ticks
        0.02,                  // seconds per tick - 50 Hz
        Paths.get("build", "sim", "slide.rlog"),
        deltaTime -> {
            // one tick of robot behaviour
        });

The timer must be constructed, and anything sim-side that reads time must be wired to it, before this call — that wiring has to happen before the robot under test is built.

It refuses to hand you a log you cannot trust¶

ScenarioRunner.run throws rather than returning quietly when any of four things is true: PsiKit's async writer queue overflowed, the file is missing or empty, it decodes to a different number of frames than ticks you ran, or the writer thread stopped making progress while the run waited for it.

That last one is why the runner paces itself against the writer. A simulator has no 50 Hz clock holding it back; left alone it outruns the writer and loses the tail of the log with no error at all.

Units and frames¶

FakeTimer.time() and advance(seconds): seconds, and it starts at zero.
Per-tick deltaTime: seconds, fixed for the whole run.
Decoded RLOG values: whatever you logged, as strings keyed by field name.

Reading the log back¶

Field keys gain a prefix. Logger.recordOutput("Slide/positionInches", x) is read back as RealOutputs/Slide/positionInches, both by RlogDecodedCompare and by RunResult.

Two runs of the same scenario must decode identically, field for field. That is what RlogDecodedCompare is for, and it is how determinism is tested rather than asserted.

What this package will not do¶

It will not run your OpMode's lifecycle. There is no init/start/loop state machine here; the scenario body is a plain lambda and you call what you want in it.
It will not schedule commands. If you use SolversLib, SolversLib still owns control flow.
It will not vary the time step. The tick is fixed, on purpose — a variable step is the single easiest way to make two runs disagree.
It will not read wall-clock time anywhere. If you introduce a System.nanoTime() on a sim path, you have broken determinism, and nothing here will catch it for you.

sim¶