[cctbxbb] indexing success rates

James Holton jmholton at lbl.gov
Fri Feb 2 13:35:56 PST 2018

While testing the new simTBX diffraction image simulator Aaron and I found
that some rather beautiful-looking images still won't index.  Subsequently,
I followed up with mosflm, which does succeed in these cases, even without
prior knowledge of the cell or space group.

I have now run this 1000 times, varying only the crystal orientation, and
found 171 cases of dials.stills_process failing to index the simulated
image whereas mosflm had no trouble, and 5 cases where mosflm failed and
dials.stills_process succeeded.  There were no overlapping cases where both
programs failed.

I have tarballed up the relevant files here:

The tarball contains a "runme.com" shell script for reproducing these
results, and also the tst_nanoBragg_forindex.py jiffy for making a test
image given a provided random-number seed.  For example:

libtbx.python ./tst_nanoBragg_forindex.py random 15

will create a file called noiseimage_001.cbf that dials.stills_process
cannot index (at least in my hands).  For those of you who don't have
mosflm installed, the tarball incluses a copy, and the "autoindex.com"
script should run on any linux system.

Any ideas as to why there is this discrepancy?  Feels like an opportunity
for a non-trivial improvement.

Something to ponder over the weekend, I suppose.  Note that I recently
checked in a few bug fixes to simTBX, but this analysis is unaffected by
them, so you shouldn't have to update your build to reproduce this.


-James Holton
MAD Scientist
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://phenix-online.org/pipermail/cctbxbb/attachments/20180202/060ceb09/attachment.htm>

More information about the cctbxbb mailing list