docs: move docs/open-items.md into the issues and docs/parity.md

docs/benchmarks.md

@@ -125,11 +125,11 @@ The smallest measured size at which Metal beats the CPU path. The break-even is
 
 | function | decision | measured |
 |---|---|---|
-| fft2+ifft2 | CPU only: no Metal path yet (see open-items.md if it is a work item), or the work is CPU-side by nature | |
-| potential build (infinite) | CPU only: no Metal path yet (see open-items.md if it is a work item), or the work is CPU-side by nature | |
+| fft2+ifft2 | CPU only: no Metal path yet (see the issues if it is a work item), or the work is CPU-side by nature | |
+| potential build (infinite) | CPU only: no Metal path yet (see the issues if it is a work item), or the work is CPU-side by nature | |
 | multislice 10 slices (plane wave, built potential) | Metal above 128² (break-even between 64² and 128²) | 64²: cpu 0.929 ms / metal 4.99 ms, 128²: cpu 11.6 ms / metal 6.53 ms, 192²: cpu 25.9 ms / metal 7.84 ms, 256²: cpu 60.1 ms / metal 10.3 ms, 512²: cpu 299 ms / metal 10.2 ms |
-| transmission functions | CPU only: no Metal path yet (see open-items.md if it is a work item), or the work is CPU-side by nature | |
-| probe build | CPU only: no Metal path yet (see open-items.md if it is a work item), or the work is CPU-side by nature | |
+| transmission functions | CPU only: no Metal path yet (see the issues if it is a work item), or the work is CPU-side by nature | |
+| probe build | CPU only: no Metal path yet (see the issues if it is a work item), or the work is CPU-side by nature | |
 | STEM scan 8x8, annular | Metal above 64² (break-even between <64² and 64²) | 64²: cpu 27.9 ms / metal 9.39 ms, 128²: cpu 176 ms / metal 13.8 ms, 192²: cpu 459 ms / metal 35.3 ms, 256²: cpu 714 ms / metal 50.6 ms, 512²: cpu 3.01e+03 ms / metal 176 ms |
-| frozen phonons 4 x multislice, built per configuration | CPU only: no Metal path yet (see open-items.md if it is a work item), or the work is CPU-side by nature | |
+| frozen phonons 4 x multislice, built per configuration | CPU only: no Metal path yet (see the issues if it is a work item), or the work is CPU-side by nature | |
 | multislice 10 slices (plane wave, potential built on the GPU) | Metal only (the GPU build of the Metal row above; its CPU counterpart is potential build + multislice) | |

docs/parity.md

@@ -234,4 +234,23 @@ counterparts are its `max_batch` and dask settings, which are not counted as mis
 - The CPU batch on up to `ExecutionOptions.maximumCPUThreads` (8 by default) threads, equal to sequential runs (exact today).
 - The constants of the CTF closed forms as parameters (`factor:` of `scherzerDefocus`, 1.5 by default as abTEM; `divisor:` of
   `pointResolution`, 6; `oversampling:` of `nyquistSampling`, 4).
-- `LobatoParameterization.PiConstant`: the exact π by default, abTEM's float32 π on request.
+- `LobatoParameterization.PiConstant`: the exact π by default, abTEM's float32 π on request.
+## Known limits and decisions
+
+Open work is in the [issues](https://github.com/mac4DSTEM/SimulatoKit/issues), including the ones closed as *not planned*
+and parked for later (quiet-run benchmarks #5, real cells #6, FFT path #43). Speed against abTEM and NumPy is in
+`docs/benchmarks.md`.
+
+- **FFT with a prime factor above 7:** lengths off vDSP that factor into 2, 3, 5 and 7 run a mixed-radix FFT; 506²
+  (2 × 11 × 23) stays on Bluestein, 1.6x slower than NumPy. The numbers are right (rtol 1e−7).
+- **Rows measured on a loaded machine:** `fft2+ifft2` at 192² to 512², multislice and frozen phonons at 192², the probe build
+  at 192² to 512² against abTEM float32; re-measure in a quiet run before changing anything.
+- **Metal:** the bounds hold to 100 slices and grids to 1024²; past 300 slices with the renormalisation is not measured.
+- **Not ported:** `CrystalPotential` (a unit potential repeated, frozen phonons per cell; its API is undecided); non-orthogonal
+  and rotated cells, `periodic=False`, `orthogonalize_cell` (the kit keeps its own structure type,
+  `docs/adr/0001-standalone-structure-types.md`); finite projection; the Kirkland, Peng and Ewald parametrisations;
+  Debye–Waller tables; `PolarMeasurements.to_diffraction_patterns` and `azimuthal_limits`.
+- **Lobato π:** the pins use `LobatoParameterization(piConstant: .abTEMFloat32)`; with the default `.exact` results differ by
+  about 2.6e−8 of the maximum.
+- **`WavesDetector` pins:** abTEM 1.0.10's own `probe.scan(..., WavesDetector(gpts=...))` raises a broadcast error; the pins
+  use `probe.multislice` then `WavesDetector(gpts).detect`, abTEM's per-wave code.

docs/status.md

@@ -4,6 +4,6 @@ SimulatoKit 0.4.0 (2026-10-22), against abTEM 1.0.10. Live: crystal cells and th
 the length, a mixed-radix FFT for most other lengths, Bluestein where a large prime factor makes it the cheaper), multislice on `.cpu` (float64) and `.metal` (float32, held to the CPU), beam tilt, the probe with
 polar aberrations C10 to C56, `GridScan`, frozen phonons, annular, pixelated, segmented and centre-of-mass detectors, `STEM.scan`, the contrast transfer function,
 source size and Poisson noise, `LineScan` and line profiles, integrated centre of mass (`integrate_gradient`, iCOM), and `WavesDetector` (the exit wave at every scan position). What is checked against what: `docs/parity.md` (37 present, 36 partial, 55 missing of 128 rows); timings against Python:
-`docs/benchmarks.md`; what is open: `docs/open-items.md`.
+`docs/benchmarks.md`; what is open: the GitHub issues; known limits: `docs/parity.md`.
 
 Tests are split in two. `SimulatoKitParityTests` holds the pinned abTEM comparisons, the truth tests, Metal against CPU and the benchmarks (111 tests; fixtures live in its `Fixtures/`); the other targets hold the fast unit tests (35 tests); `SimulatoKitTestSupport` holds the helpers both use. `swift test -c release --parallel --skip SimulatoKitParityTests` runs the fast half; the plain `swift test -c release --parallel` runs all 146.

tools/benchmarks/merge.py

@@ -93,7 +93,7 @@ def sh(*cmd):
         out.append(f"| {f} | {why} | |")
         continue
     if not both:
-        why = "CPU only: no Metal path yet (see open-items.md if it is a work item), or the work is CPU-side by nature"
+        why = "CPU only: no Metal path yet (see the issues if it is a work item), or the work is CPU-side by nature"
         out.append(f"| {f} | {why} | |")
         continue
     wins = [s for s in sorted(both) if both[s]["metal"] < both[s]["cpu"] * 0.9]