Ticket #4986 (closed: wontfix)

Opened 9 years ago

Last modified 5 years ago

Evaluate the speed of finding detector for a given Q position

Reported by: Janik Zikovsky Owned by: Janik Zikovsky
Priority: critical Milestone: Release 2.1
Component: Mantid Keywords:
Cc: saviciat@… Blocked By:
Blocking: Tester: Andrei Savici

Description

We want to see how much time it would take to locate the detector ID that contributed to a given Q point, as compared to storing the Zeroes of every detector id and every bin and the memory that uses.

Change History

comment:1 Changed 9 years ago by Janik Zikovsky

  • Status changed from new to accepted

comment:2 Changed 9 years ago by Janik Zikovsky

  • Cc saviciat@… added

comment:3 Changed 9 years ago by Janik Zikovsky

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

Hi Nick,

You asked me to consider whether it would be possible to calculate the contributing pixels/bins to an inelastic MD workspace on the fly, rather than doing the calculation at the beginning and carrying one MDEvent for each bin of each pixel (possibly with 0 weight).

After some discussion with Andrei I've come to the conclusion that it is very unlikely to be possible to calculate this on the fly. The main problem is that a nice regular shape in Q-space will be distorted when converted to detector/bin space. Even converting each vertex would not be sufficient because the shapes will be curved. It will be very tricky to get it right, and likely computationally intensive; so I don't think it is worth pursuing.

The approach of converting from detector/bin to Q is much more straightforward, at the cost of added memory. If only a small region of Q-space is of interest, the algorithm can reject pixels falling outside the range, saving memory.

Cheers,

Janik Zikovsky Scientific Data Analysis Group, Spallation Neutron Source

comment:4 Changed 8 years ago by Andrei Savici

  • Status changed from verify to verifying
  • Tester set to Andrei Savici

comment:5 Changed 8 years ago by Andrei Savici

  • Status changed from verifying to closed

comment:6 Changed 5 years ago by Stuart Campbell

This ticket has been transferred to github issue 5832

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