Ticket #3565 (closed: wontfix)

Opened 9 years ago

Last modified 5 years ago

MaskBins is very slow on POWGEN

Reported by: Peter Peterson Owned by: Janik Zikovsky
Priority: minor Milestone: Release 2.0
Component: Mantid Keywords:
Cc: Blocked By:
Blocking: Tester: Nick Draper

Description

While trying out some things with SNSPowderReduction I discovered that when processing histogram nexus files (PG3_4565_histo.nxs) which have an excessive time-of-flight range which needs to be trimmed down it takes much longer than it should (2.7 hours, forced to be single threaded). I believe that it could be sped up by creating a second version of MatrixWorkspace::maskBin which takes a range of bin indices so it does the index checks only once per range of time bins that are being masked.

Change History

comment:1 Changed 9 years ago by Russell Taylor

Shouldn't you be using CropWorkspace (might need to make event-aware) here? Or some other kind of event filtering? MaskBins was really conceived for cutting out narrow ranges somewhere in the center of the time range - e.g. a prompt pulse.

comment:2 Changed 9 years ago by Nick Draper

  • Milestone changed from Iteration 30 to Iteration 31

Bulk move of tickets to iteration 31 at the iteration 30 code freeze

comment:3 Changed 9 years ago by Janik Zikovsky

  • Status changed from new to verify
  • Resolution set to wontfix

My guess is that the workspace went managed, if the # of tof bins was large. There isn't much to do to speed up all that disk access. An option would be to crop the workspace when loading, to avoid having to go managed in the first place.

comment:4 Changed 9 years ago by Nick Draper

  • Status changed from verify to verifying
  • Tester set to Nick Draper

agreed

comment:5 Changed 9 years ago by Nick Draper

  • Status changed from verifying to closed

comment:6 Changed 5 years ago by Stuart Campbell

This ticket has been transferred to github issue 4412

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