Loading Monitors on EventWorkspaces

[Owen Arnold]

There is an option fro MonitorsAsEvents on LoadEventNexus. Having this selected or deselected always results in having monitors as Event Workspaces. Tested using POLREF00009955.nxs

[Nick Draper]

Bulk move to assigned at the introduction of the triage step

[Federico Montesino Pouzols]

Add new 'MonitorsAsEvents' property in LoadNexusMonitors, re #8990

Changeset: e5e77eeed220019ffdc0d56ae855dfbcac63413d

[Federico Montesino Pouzols]

Support for MonitorsAsEvents option, re #8990

Changeset: 4f1b8d1f131960b069b88c9badc467efc0264cdd

[Federico Montesino Pouzols]

fix doc and clean comments, re #8990

Changeset: 03f3307e8b84edd3060e2b6a51bc5943aafc1be7

[Federico M Pouzols]

This is what I was experiencing:

Untick 'Load Monitors' => correct behavior, you just get the event workspace and no monitor workspace

But when I tick 'Load Monitors' I get the following (regardless of whether I tick or not 'MonitorsAsEvents'):

• with POLREF00004699.nxs (does not have event monitor data, hasEventMonitors()==0) : all monitor workspaces are Workspace2D

• with POLREF00009955.nxs (has event monitor data, hasEventMonitors()==1): all monitor workspaces are EventWorkspace

I think the issue lies in that the LoadEventNexus algorithm is using LoadNexusMonitors as a child algorithm to load monitors. LoadNexusMonitors will create an EventWorkspace if the input file contains event monitors, and a Workspace2D otherwise. To me this looks consistent. LoadEventNexus provides the option 'MonitorsAsEvents' but it seems that such functionality was not implemented (for non event monitors) or was lost when other changes were made.

LoadEventNexus is relying on LoadNexusMonitors which will load into the appropriate type of workspace depending on what data is found in the file (EventWorkspace if there are event data or Workspace2D if there are spectra). This ignores the 'MonitorsAsEvents' option as noted in the ticket description. LoadEventNexus calls LoadNexusMonitors which finds events in monitors (POLREF00009955) and constructs an EventWorkspace.

Solution: a new property 'MonitorsAsEvents' has been added to LoadNexusMonitors(), with a default value of True (consistent with previous behavior). If you set it to false, then LoadNexusMonitors will not try to load events and will generate a Workspace2D.

Note that the documentation of LoadNexusMonitors is outdated and says that it only loads into Workspace2D, and only SNS files. This is being fixed in ticket #10595. There's another ticket related to LoadNexusMonitors: #9248, and as suggested by Anders I might be opening a maintenance ticket for LoadEventNexus.

To test:

Use at least:

• a file that has event monitor data (example: POLREF00009955.nxs, from ISIS machines you find it under \\ISIS\inst$\NDXPOLREF\Instrument\data\cycle_14_4, or contact me)
• a file without event monitor data (example: POLREF00004699.nxs, found in Test/AutoTestData/UsageData)

Apply/execute LoadEventNexus on these files, enabling LoadMonitors, and check that

• you get the monitor data into an EventWorkspace if you select/tick 'MonitorsAsEvents',
• but you get them into a Workspace2D if you deselect/untick 'MonitorsAsEvents'.

This should be the behavior for both types of files.

By mistake I called this a "feature/..." where it should be 'bugfix/...' branch, although after finding out what was the issue it's not clear if this is a bugfix or a feature that is being implemented.

[Martyn Gigg]

I can't be 100% sure but I think this may have broken a system test: ​http://builds.mantidproject.org/job/develop_systemtests_rhel6/lastCompletedBuild/testReport/SystemTests/StepScan/StepScanWorkflowAlgorithm/

There is an error message:

LoadNexusMonitors-[Error] Error in execution of algorithm LoadNexusMonitors:
LoadNexusMonitors-[Error] NXopendata(data) failed
LoadEventNexus-[Error] Error while loading the monitors from the file. File may contain no monitors.

[Federico Montesino Pouzols]

back to old, in case this is breaking a systemtest, re #8990

Changeset: 52253c0f9e80f0e911dedfcc5066c205b52b8fea

[Federico Montesino Pouzols]

Catch exception by ref, re #8990

Changeset: ce82c1046910e9aa350dca0c8c468767f3ccbb32

[Federico M Pouzols]

Yes, this ticket was breaking the StepScan system test. That test loads a file that happens to be NeXus, requesting to load monitors but not as event data. But the file only has event data for monitors so it is not possible to load histogram data. This has been fixed by adding a check for that kind of inconsistency, and when it happens the code will show a warning and load what can be loaded. Note that there are more cases in LoadEventNexus and LoadNexus... that need to be handled more gracefully. That is being done in tickets #9248 and #10619. System tests seem to have been happy for a while now.

For an explanation of what was happening, and how to test, go up to comment:7.

[Federico M Pouzols]

To test: please follow instructions at the end of comment:7

[Roman Tolchenov]

The algorithm works fine but there is a conflict in LoadNexusMonitors.h when merging it into master.

[Federico M Pouzols]

Aha, two method declarations had been added in the same place from two different branch. But they're compatible. I've just merged master into this branch and sorted out the conflict. Hopefully it will work well now...

[Federico Montesino Pouzols]

Merge branch 'master' into feature/8990_loading_monitors_or_not_in_load_event_nexus

Conflicts:

Code/Mantid/Framework/DataHandling/inc/MantidDataHandling/LoadNexusMonitors.h

Two methods were added in the same place, but they are not conflicting

Full changeset: ​7f700385005af9a4ce1dc49e7412104e08d9722c

[Federico Montesino Pouzols]

Merge branch 'master' into feature/8990_loading_monitors_or_not_in_load_event_nexus

Full changeset: ​788886192d627e3a5abc75b2f54bee01a8561126

[Roman Tolchenov]

Merge remote-tracking branch 'origin/feature/8990_loading_monitors_or_not_in_load_event_nexus'

Full changeset: ​1030fae41630d29dfd7b3a6d1ea5c354bbe3fe35

[Stuart Campbell]

This ticket has been transferred to github issue ​9833