krahn at niehs.nih.gov
Mon Nov 30 17:41:42 GMT 2009
David Brown wrote:
> Is a CIF a fixed archive, a place
> where we entomb a fact of nature, or is it an evolving document that
> carries it own history along with it?
CIF is becoming the standard data format for working crystallography
experiments, not just an archival format. Maybe the goal should be that
_variant components can be removed from archival CIFs, in a way that
does not complicate non-variant data.
To me, the _diffrn_radiation_wavelength_determinaton approach is
confusing. The wavelength id is defined mainly for multiple wavelength
experiments. Using _variant, multiple wavelengths might be defined like
1 final 1.23456
1 prelim 1.25
2 final 1.00
Maybe use "_variant_id" instead of "_variant_variant"?
Maybe the _variant_* items should include an identifier as to what
primary value is being varied, when one exists. In this case, the
wavelength value is the primary varying value, and all others are derived.
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