NOMAD calibration crashes mantid

[Peter Peterson]

Run

CalibrateRectangularDetectors(

Instrument="NOM", RunNumber=23234, MaxOffset=.1, CrossCorrelation=False, PeakPositions = [2.0600,1.2615,1.0758,0.8920,0.8186,0.7283,0.6867,0.6307,0.5947,0.5642,0.5441,0.5150,0.4996,0.4768,.4645,.4205,.3916,.3499,.3257,.3117], PeakWindowMax=.1, Binning=[.3,-.0004,3], CrossCorrelation = False, DiffractionFocusWorkspace=False, GroupDetectorsBy="All", FilterBadPulses=True, SaveAs="calibration", OutputDirectory="/tmp")

The script crashes. Hopefully this can be characterized and fixed quickly.

Investigation

1. gdb shows that the crash (segmentation fault) comes from algorithm FindPeakBackground;

2. In FindPeakBackground::exec(): l0 and n are calculated with X vector of spectrum 0. This seems to cause issue during working with a multiple spectra workspace;

3. In FindPeakBackground::estimateBackground(), if the number of background points defined by (i_min, p_min) and (p_max, i_max) are too few, the estimated background may not be correct. For example, if there is only 1 background point in the range, the estimated background is flat, which can be way off. Therefore, there should be a checking mechanism to define the quality of background estimation;

4. Zero background is output in some situation though the background may not be zero. There should be some message about this to be exported.

[Peter Peterson]

Re #8878. Adding CropWorkspace to reduce memory usage.

Changeset: 926b34e72f8252e392f1e68d5b29bb46926d4acd

[Peter Peterson]

Re #8878. Adding checks for data actually in the workspace.

Changeset: 61057dddceecd08d6321e998bb47582abf5b3dbc

[Peter Peterson]

Re #8878. Don't double calculate the background.

Changeset: 9e0bb28cb36aabeec0c953472c04c5afb6456599

[Peter Peterson]

The decision is to make FindPeakBackground::estimateBackground a public static method. This will allow for it to be called directly rather than by creating a subalgorithm and temporary workspace. This is what the actual bug was caused by lots of algorithm/workspace creation and destruction.

[Peter Peterson]

Other more pressing matters are taking over. This is being pushed to the next release.

[Wenduo Zhou]

Fixed the segmentation fault. Refs #8878.

With the macro for OpenMP removed, GetDetOffsetMultiPeak did not crash on NOMAD's data but executed successfullly.

Changeset: deac45bbc76d8ebbbf465b8b50db010befd986da

[Wenduo Zhou]

Refactored and cleaned codes. Refs #8878.

Changeset: 21f66d446833773b122ca989a55d1d0fb06a0f8a

[Wenduo Zhou]

For tester

CalibrateRectangularDetectors does not crash on any data but only on NOMAD run 23234. So I strongly suggest that the tester is at SNS side in order to get access to the data.

1. Before merging the branch to master, run the attached script to see how it crashes;
2. Merge the branch to master, and rerun the script to check whether it crashes still;
3. Check whether unit tests and system tests are passed as refactoring changes the structure of the codes significantly.

[Wenduo Zhou]

Made core methods to be static. Refs #8878.

Changeset: 44ebe6190ae9e7bfa53f09a59fbbe645cbbf6492

[Wenduo Zhou]

Added debugging information. Refs #8878.

Changeset: e72527d983de60b5ec5af6ae4969fc55339cf3f8

[Wenduo Zhou]

With the bug fixing in ticket #9020 (FindPeakBackground) and #9033 (FindPeaks), the problem reported by this ticket does not exist anymore. So this ticket is closed as duplicate. Branch bugfix/8878_nomad_calibration_crash has been removed from github.

For tester

You can update your master branch. Do not merge any branch. Run the script in the ticket description.

[Peter Peterson]

It works on master as commented.

[Stuart Campbell]

This ticket has been transferred to github issue ​9722