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GDA: Axis constraint Scannables naming convention is unintuitive ('You' engine)

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@robwalton is already working on this.

Since May 3, 2012.

Assessment

Difficulty
5/5
Estimated time
Over a week
Newbie friendliness
25/100
Issue type
Feature
Clarity
Needs clarification
Activity status
Stale
Tech stack
python
Domain
tooling

Research direction

Start by tracing how GDA creates axis-constraint Scannables and how physical-axis and hkl scans are handled. Compare the proposed last-value lookup with the grouped-Scannable approach, paying particular attention to avoiding two motor moves. Done means the naming convention is intuitive without causing duplicate moves when an axis is scanned while hkl is held still.

Written by the indexing model from the issue text.

Description

Where an axis (e.g. gamma) may be fixed by a constraint an <axis_name>_con Scannable is created rather than an <axis_name> Scannable in order to avoid a namespace clash with that axis' actual Scannable. This is unintuitive.

One solution is for Diffcalc to read up the last set value for an axis when that axes is constrained.

However if the axis is Scanned while hkl is held still this would result in two motor moves. This could be resolved by making the physical axis Scannables the same level as the hkl Scannable and treating them as a group, although this is a pretty heavy solution.

Dominant language
Python
Stars
22
Forks
18
PR merge metrics
No merged PRs in 30d

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