add FilterByTime functionality

[KyleQianliMa]

Description of work

This PR adds the function of "FilterbyTime to the LoadEventAsWorkspace2D function by introducing two optional input fields: "FilterByTimeStart" and "FilterByTimeStop". If both are left empty, it will by default not apply any filter. If either start or stop is entered, it will filter from start time till end or start till end time.

The functionality is implemented by introducing "BankPulseTime" and "PulseIndexer". Once "FilterByTimeStart" and/or "FilterByTimeStop" are introduced, a TimeROI is created from BankPulseTime, then this TimeROI is used to extract event_index using PulseIndexer, then a for loop is used to loop through the filtered event_index to generate "Y" of workspace.

Related to story 6294

Summary of work

Add FilterByTime functionality similar to the workflow of LoadEventNexus(FilterByTime) + Integeration.

Fixes #xxxx.

Further detail of work

To test:

Run python scripts as below:
ws1 = LoadEventAsWorkspace2D(Filename = "BSS_11841_event.nxs", OutputWorkspace = "outputWS",
FilterByTimeStart = 0.0, FilterByTimeStop = 5.0,
XCenter = 1.54, XWidth = 0.1,
Units = "Wavelength"
)

ws2 = LoadEventNexus(Filename = "BSS_11841_event.nxs", OutputWorkspace ="outputWS2",
FilterByTimeStart = "0.0", FilterByTimeStop = "5.0")

ws3 = Integration(InputWorkspace = "outputWS2", RangeLower = 0.0, OutputWorkspace = "outputWS3")

ws3.getAxis(0).setUnit("Wavelength")
xBins = [1.463, 1.617]
for i in range(ws3.getNumberHistograms()):
ws3.setX(i, xBins)
CompareWorkspaces(ws1,ws3)

Alternatively:
In Mantid, open LoadEventAsWorkspace2D, load mantid/build/ExternalData/Testing/Data/UnitTest/BSS_11841_event.nxs. Set FilteByTimeStart and FilterByTimeStop to specific values(i.e. 0 and 5), set XCenter to 1.54, XWidth to 0.1, units = Wavelength and generate workspace.

Then open LoadEventNexus, load same .nxs file, set FilterByTimeStart/FilterByTimeStop to same values as before and create another workspace. Then use Integration to integrate this workspace, set RangeLower = 0 and generate workspace. Compare the Y values of the workspace. This can be done by plotting the data or look at the data specifically.

Another wayt to test is follow the LoadEventAsWorkspace2DTest.h to directly call LoadEventAsWorkspace2D, LoadEventNexus, Integrate from command line.

---

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[jmborr]

in the pull request description, can you write a manual test I can run in the workbench?

[KyleQianliMa]

in the pull request description, can you write a manual test I can run in the workbench?
I wrote that in the wrong place and it got commented out. Should I also write something that can be directly exectued from commandline of workbench?

[jmborr]

in the pull request description, can you write a manual test I can run in the workbench?
I wrote that in the wrong place and it got commented out. Should I also write something that can be directly exectued from commandline of workbench?

Yes, a few python statements that I could execute in the workbench would be best

[KyleQianliMa]

I've updated the test instructions

[jmborr]

This script pass

from mantid.simpleapi import HFIRSANS2Wavelength, LoadEventAsWorkspace2D, LoadEventNexus
filename="/HFIR/CG3/IPTS-23782/nexus/CG3_4829.nxs.h5"

LoadEventNexus(
    Filename=filename,
    OutputWorkspace="CG3_4829_1",
    FilterByTimeStart=60,
    FilterByTimeStop=120
)
HFIRSANS2Wavelength(InputWorkspace="CG3_4829_1",  OutputWorkspace="CG3_4829_1")


LoadEventAsWorkspace2D(
    Filename=filename,
    OutputWorkspace="CG3_4829_2",
    FilterByTimeStart=60,
    FilterByTimeStop=120
)

# Accept if workspaces differ by one count, but no more
CompareWorkspaces(Workspace1="CG3_4829_1", Workspace2="CG3_4829_2", Tolerance=1)

The rest looks 👌
@KyleQianliMa You still need to fix the conda build. Have you already tried?

[KyleQianliMa]

I'm not sure why it failed windows testing. The console output says all test passed. I can't seem to understand where it failed. Here is a link to the console log
https://builds.mantidproject.org/job/pull_requests-conda-windows/7015/console

Parsing console log (workspace: '/jenkins_workdir/workspace/pull_requests-conda-windows')
12:35:17 [MSBuild] -> found 1 issue (skipped 0 duplicates)

[KyleQianliMa]

@jmborr Could you re-run the tests using CG3_4829.nxs.h5 file? It seems like all the check passed somehow. Previously some tests mysteriously failed, so I rebased the repo and pushed again. That caused some problem while I resolve merge conflict. I believe now everything should be ok.