2D Classification Failure

Hello all,

I am experiencing a strange failure mode when processing helical data. The failure appears to be caused by the ‘Force max over pose/shifts’. Using the same selected particles, one job fails with ‘Force max over pose/shifts’ switched off while the other succeeds with it switched on. All previous jobs had it switched off (which I prefer in this case) and worked well.


Any ideas on how to fix this problem and allow me to run with the force max switched off again?

Thanks!

Charlie

Force/max off takes a lot longer to converge. How many iterations did you run it for?

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If you left the number of iterations at default, it won’t converge, exactly as Oli says. With Force Max off, I had one dataset which needed 120 iterations before I was happy with what I was seeing in the 2D classes. Other things to tweak as the initial sigma anneal (although 99% of the time I leave this alone), class uncertainty (I often get nice results with 5 or 8 instead of the default 2, and a second round of 2D seems to find less junk hiding in nice classes) and of course iterations (I like 3 full final iterations, seems to work nicely) and particles per class (depending on number of classes and size of dataset).

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The job from the first image I killed after a few early iterations as I had never seen a job that starts this way end up in any decent classes. The settings for that killed job are:

Classes: 100
Uncertainty: 5
Force max: False
Online EM: 40
Final Full: 5

I will restart and allow this to complete now.

At an earlier stage with this pipeline, while cleaning, I had run with the below custom settings (see imaged, based on some other comments from Oli about clean up) and never saw this early iteration state. I should also say that initial iterations on this jobs were clearly just misaligned filaments rather than blobs.

Class: 100
Uncertainty: 1
Force max: False
Online EM: 40
Final Full: 5
Iteration to start annealing sigma: 200
Re-center 2D classes: False

UPDATE:

So big egg on my face here - allowing the jobs with that strange initial iterations appearance to complete yields ‘normal’ results.

Lesson learned! Thank you both for your inputs!

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