SaveNexusProcessed and LoadNexusProcessed changes masked detectors

[wdzhou]

This issue was originally TRAC 8036

The defect is found while running the attached script. As the final result of the script, the result of the division in last step (stored in workspace NOM_18251) has non-zero uncertainties. But do the division between 2 workspaces that are loaded from the saved Nexus file (NOM_18250_Foc.nxs and NOM_18251_Foc.nxs) in this script renders a result with zero uncertainties. Theoretically, it should be the same as 'NOM_18251'.

Some investigation was made. And it is found that the detectors in the workspace loaded from the processed Nexus files are flagged as 'masked'. Thus algorithm BinaryOperation just put ZERO (value and uncertainties) in the output workspace.

Thus the problem must occur in either LoadNexusProcessed or SaveNexusProcessed when they deal with some spectra with multiple detectors, among which some detectors are masked.

[wdzhou]

@NickDraper (2014-02-14T11:04:54):
Bulk move to assigned at the introduction of the triage step

[wdzhou]

http://trac.mantidproject.org/mantid/raw-attachment/ticket/8036/problem.py
(uploaded by @wdzhou on 2013-09-27T02:34:06)

---

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed in 7 days if no further activity occurs. If you feel this is incorrect please comment to keep it alive, with a reason why.

To prevent closure, e.g. for long-term planning issues, add the "Never Stale" label.

[stale]

This issue has been closed automatically. If this still affects you please re-open this issue with a comment so we can look into resolving it.