Conversation
| case 215: | ||
| return get_path("DREAM-high-flux-tof-lookup-table.h5") | ||
| if full_beamline: | ||
| return get_path("DREAM-high-flux-tof-lut-5m-80m.h5") |
There was a problem hiding this comment.
In principle, this should not change existing results.
I will double-check and if that is indeed the case, maybe we don't need to make new files, but we can replace the old ones?
There was a problem hiding this comment.
Update: In the new full beamline tables, we are more lenient with the variance threshold for masking. We therefore are keeping more events between the two frames, where neutron paths overlap.
This means that the results change a little.
Because of this, I will not replace the old ones with the new ones.
There was a problem hiding this comment.
Does that mean in practice we would not actually want to use a unified table? Or does the threshold need adjusting, e.g., balancing relative vs absolute variance, or factoring in some other parameter?
There was a problem hiding this comment.
Sorry, I think this required more context.
When I first made the new tables, I got this
where I could see that at low distances, the values were being masked because of large uncertainties, which makes sense; the further you are away from the instrument, the more rays spread out and the lower the uncertainty.
So I changed the (single) threshold I had from 0.02 to 1.0, to obtain
Looks better at low distances, but the gap between the two frames towards the top has now been filled.
Maybe the threshold should be distance-dependent? Can we come up with a good rule/expression/dimensionality argument for a distance-dependent uncertainty threshold?
There was a problem hiding this comment.
Does that mean in practice we would not actually want to use a unified table?
I think we definitely want to try and use a unified table if possible, for the simplicity it provides.
There was a problem hiding this comment.
Yes, that is what I understood and was referring to. My question is basically: We probably want to discard events in the gap (right?), while still supporting lookup at small distances. How can we reconcile the two?
There was a problem hiding this comment.
Here is the difference in results between the 2 tables: as expected, only in the region between the two frames to we see differences.
2 participants
We compute full-beamline lookup tables and add them to the data registry.
Needs scipp/essreduce#308