Import particle poses and random subset

Import and Export
1

I have just found out today that importing particle poses from a star file require the randomSubset column. Does this imply that cryosparc directly take the random subset from Relion for refinement? I am just curious and may have some follow-up questions.

Thank you for your time!

Best,
Chen

2

Hi @chenzhao,

We do require the rlnRandomSubset column to import particle poses. If you then use these imported particles in a New homogeneous refinement, there is a parameter that can be set that will determine whether these splits are used (“Force re-do GS split”). The imported split will only be used if this parameter is disabled, otherwise it will re-split particles.
All other refinements (heterogeneous, non-uniform, legacy homogeneous) will always randomly re-split particles, with the exception of local refinement, which currently requires half-map splits to already be assigned in the particles dataset. So, the rlnRandomSubset field will only be used if imported particles are used directly in a local refinement, or in a New homogeneous refinement with re-splitting disabled.

Hope this helps! Best,
Michael

2 Likes
3

Hi @mmclean,

Thank you so much for your detailed explanation which cannot be explained more clearly :slight_smile: I have always assumed that cryosparc redo the GC split, but now I learned that it is not always the case :stuck_out_tongue:

Best,
Chen

2 Likes