Bug on the nGEM loader

draspi · December 19, 2024, 7:25pm

Expected behavior

Setting the two parameters “MinEventsPerFame” and “MaxEventsPerFame” should rejet any event in a frame wih a number of event outside this range.

Actual behavior

any event is loaded, even from frames with a number of events outside the selected range is loaded on the workspace

Steps to reproduce the behavior

Select two different ranges of the EventsPerFrame on the same run, and check that the two worspace will be identical

Platforms affected

All the imaging performed with the nGEM detector on the ISIS instruments INES and IMAT

RichardWaiteSTFC · January 6, 2025, 1:15pm

Thanks for this report - I can reproduce this bug and have opened an issue on github here (where you can follow it’s progress)

github.com/mantidproject/mantid

LoadNGEM not respecting Min/MaxEventsPerFrame

opened 12:58PM - 06 Jan 25 UTC

RichardWaiteSTFC

Bug

**Original reporter:** [draspi](https://forum.mantidproject.org/u/draspi) Repor…ted via user forum https://forum.mantidproject.org/t/bug-on-the-ngem-loader/926 **Describe the bug** LoadNGEM not respecting Min/MaxEventsPerFrame - any event is loaded, even from frames with a number of events outside the selected range is loaded on the workspace. **To Reproduce** (1) Run this script ``` from mantid.simpleapi import * import matplotlib.pyplot as plt from mantid.plots.utility import MantidAxType ws = LoadNGEM(Filename=r'C:\mantid-conda\mantid\build\ExternalData\Testing\Data\UnitTest\GEM000005_00_000_short.edb', OutputWorkspace='ws', MinEventsPerFrame=0, MaxEventsPerFrame=0) fig, axes = plt.subplots(edgecolor='#ffffff', num='ws-1', subplot_kw={'projection': 'mantid'}) axes.plot(ws, color='#1f77b4', label='ws: spec 1', wkspIndex=0) axes.plot(ws, color='#ff7f0e', label='ws: spec 100', wkspIndex=99) legend = axes.legend(fontsize=8.0).set_draggable(True).legend fig.show() ``` (2) Produces this ![image](https://github.com/user-attachments/assets/59e70592-9de9-4e0d-af97-5bf454df3949) Would expect there to be no counts? **Expected behavior** Setting the two parameters “MinEventsPerFame” and “MaxEventsPerFame” should rejet any event in a frame wih a number of event outside this range. **Additional context** All the imaging performed with the nGEM detector on the ISIS instruments INES and IMAT

RichardWaiteSTFC · January 16, 2025, 4:26pm

This bug fix in this PR has been merged, it has made it into v6.12

github.com/mantidproject/mantid

Fix bug in LoadNGEM where Min/MaxEventsPerFrame were not respected

mantidproject:main ← mantidproject:38558_LoadNGEM_not_respecting_min_max_events

opened 04:53PM - 06 Jan 25 UTC

RichardWaiteSTFC

+20 -8

### Description of work Added loop to clear events in frame if the current fram…e is not good (i.e. number of events outside Min/Max limits set) in preparation for next frame (don't know if that is the best way to do it).. The issue was here https://github.com/mantidproject/mantid/blob/22bed2110eee1945c2b6a4035bfc81d93e184056/Framework/DataHandling/src/LoadNGEM.cpp#L74-L88 If the statement on L74 is false then `eventsInFrame` doesn't get cleared - such that the sum over all `eventsInFrame[i].getNumberEvents()` is not equal to `eventCountInFrame` Fixes #38558 **Report to:** [draspi](https://forum.mantidproject.org/u/draspi) ### To test: (1) Follow instructions on the issue (2) For `MinEventsPerFrame=0` and `MaxEventsPerFrame=0` the workspace should have no counts (`ws.getNumberEvents() = 0`) (3) If `MinEventsPerFrame` and `MaxEventsPerFrame` are not set then the resulting figure should look like the one in the issue. ### Reviewer Please comment on the points listed below ([full description](http://developer.mantidproject.org/ReviewingAPullRequest.html)). **Your comments will be used as part of the gatekeeper process, so please comment clearly on what you have checked during your review.** If changes are made to the PR during the review process then your final comment will be the most important for gatekeepers. In this comment you should make it clear why any earlier review is still valid, or confirm that all requested changes have been addressed. #### Code Review - Is the code of an acceptable quality? - Does the code conform to the [coding standards](http://developer.mantidproject.org/Standards/)? - Are the unit tests small and test the class in isolation? - If there is GUI work does it follow the [GUI standards](http://developer.mantidproject.org/Standards/GUIStandards.html)? - If there are changes in the release notes then do they describe the changes appropriately? - Do the release notes conform to the [release notes guide](https://developer.mantidproject.org/Standards/ReleaseNotesGuide.html)? #### Functional Tests - Do changes function as described? Add comments below that describe the tests performed? - Do the changes handle unexpected situations, e.g. bad input? - Has the relevant (user and developer) documentation been added/updated? Does everything look good? Mark the review as **Approve**. A member of `@mantidproject/gatekeepers` will take care of it. ### Gatekeeper If you need to request changes to a PR then please add a comment and set the review status to "Request changes". This will stop the PR from showing up in the list for other gatekeepers.

Thanks for reporting the bug.