docs(omny): TODO to port always-defined tomo_alignment_fit from flomni

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
2026-09-21 15:03:44 +02:00
parent 5b688df428
commit e802d55112
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+# TODO: port "always define `tomo_alignment_fit`" to OMNY now that it's landed on Flomni
+
+**Status: implemented on Flomni** (commit `5b688df`, branch
+`fixes/flomni_beamtime_2`), not yet ported to OMNY.
+
+## Problem (as seen on Flomni)
+
+The `tomo_alignment_fit` global var was deleted by `reset_tomo_alignment_fit()`
+(on stage-in and at the start of a new alignment) and never created at
+startup. Manual offset tweaks from the client failed with an undefined
+variable:
+
+```python
+fit = flomni.client.get_global_var("tomo_alignment_fit")   # -> None
+fit[0][2] += 5.0   # x offset, microns  -> TypeError
+```
+
+## What Flomni does now (`flomni/flomni.py`)
+
+- `reset_tomo_alignment_fit()` writes `np.zeros((2, 5)).tolist()` instead of
+  calling `delete_global_var`, so the var is always defined.
+- New `ensure_tomo_alignment_fit()` sets the zero fit **only if**
+  `get_global_var("tomo_alignment_fit") is None`. It is called from
+  `Flomni.__init__`, so an existing fit survives a client restart.
+- `get_alignment_offset()` is unchanged; with zeros it prints zero offsets
+  instead of the "Not applying any alignment offsets" message. Same result.
+
+Fit layout (row 0 = x, row 1 = y):
+
+```
+# x amp, phase, offset, y amp, phase, offset, 3rd order amp, 3rd order phase
+#  0 0    0 1    0 2     1 0    1 1    1 2       1 3           1 4
+```
+
+## What to do on OMNY
+
+`omny/omny_alignment_mixin.py` still has the old behaviour:
+
+- `reset_tomo_alignment_fit()` (~line 57) does
+  `self.client.delete_global_var("tomo_alignment_fit")`.
+- Nothing defines the var at startup. `OMNY.__init__` is in `omny/omny.py`
+  (~line 557).
+
+Steps:
+
+1. Change `reset_tomo_alignment_fit()` to write `np.zeros((2, 5)).tolist()`.
+2. Add `ensure_tomo_alignment_fit()` exactly as on Flomni.
+3. Call it from `OMNY.__init__` (after `self.client` is set).
+4. Check the callers: at the time of writing, nothing in `omny/` calls
+   `reset_tomo_alignment_fit()` apart from its definition, so decide where
+   OMNY should reset the fit (start of an alignment / sample transfer),
+   mirroring Flomni's `ftransfer_flomni_stage_in()` and
+   `XrayEyeAlign._align_impl()`.
+5. `read_alignment_offset()` in the OMNY mixin builds the fit as `np.zeros((2, 5))`
+   and stores it with `set_global_var`, so it needs no change.
+
+LamNI does not reference `tomo_alignment_fit` at all (checked by grep), so no
+action there.