[Cod-bugs] Undercounting of structure factors

[Andrius Merkys]

Hi Thomas,

Thank you for your message and sorry about the delay to respond.

We in the COD are aware about this undercounting. The way we would like
to deal with it is to extract the HKL data embedded in CIF files and
place it in separate HKL files, so that the representation of HKL in the
COD be homogeneous.

However, currently we lack workforce to implement this. If you would be
willing to contribute a program for HKL data extraction, we could
include it in the data processing pipeline. Our requirements for the
program are free/libre open source software, usable unsupervised in
Linux command line environment.

Best wishes,
Andrius Merkys (on behalf of the Crystallography Open Database)

On 2021-03-23 18:30, Thomas Munro wrote:
> Hi,
> I’m a huge fan of your work. It’s tragic that the CCDC is still so
> closed-minded.
> I'm not a trained crystallographer, so I may have misunderstood this,
> but I notice that only a small fraction of COD entries are returned
> under the “has Fobs” filter. This seems to refer to having a separate
> hkl file. But checking recent structures without one, I find that
> about half of them have the hkl data embedded in the cif. So I thought
> it might be useful for users to flag these as well, so that the filter
> would return many more examples. Presumably it would be
> straightforward to detect them with a regular expression, or even just
> by their much larger file size, and update the indexing. Just a
> thought! Keep up the good work.
> Cheers,
> Thomas

-- 
Dr. Andrius Merkys
Vilnius University Institute of Biotechnology, Saulėtekio al. 7
LT-10257 Vilnius, Lithuania

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