On 29.08.2008, at 03:16, Ian Tickle wrote:
You don't really need a program: e.g. if there are N non-H atoms
refined, then there are 4N params (isotropic B) or 9N (aniso). TLS
adds
19 params per group to the isotropic count. You count unique
reflections.
That simple count doesn't take into account restraints, however.
A while ago I looked at data/parameter ratios in PDB structures and
was surprised at how small they can get. There are some histograms
with a bit of analysis at
http://dirac.cnrs-orleans.fr/plone/Members/hinsen/data-parameter-
ratio-in-x-ray-structure-determination
for those who are interested.
Konrad.
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Konrad Hinsen
Centre de Biophysique Moléculaire, CNRS Orléans
Synchrotron Soleil - Division Expériences
Saint Aubin - BP 48
91192 Gif sur Yvette Cedex, France
Tel. +33-1 69 35 97 15
E-Mail: [EMAIL PROTECTED]
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