Sorry,
Arie, genetic algorithm (or its relatives) does not shuffle electron
density, just atom coordinates. Taking them the procedure (not GA itself)
calculates structure factors and compares them to the "observed" structure
factors (their squares, or intensities). Decision making process of GA is
not based on the differences in electron density, but on |Fo|^2-|Fc|^2.
Lubo
On Thu, 17 Dec 2015, A. van der Lee wrote:
I agree with Yaroslav Filinchuk's thoughts:
"However, the "structure solution in direct space" does not attempt to
work in the reciprocal space - all the manipulations are done in the
direct space."
RMC, normal MC, genetic algorithms, they all shuffle electron density in some
or another way in real space. So 'real space structure solution' sounds the
best, and 'real space' is better than 'direct space' as to avoid confusion
with 'direct methods'.
Arie
ps: we should propose a new possible data value for
_atom_sites_solution_primary
By the way the data value vecmap (real-space vector search) is, I suppose,
equivalent to a real-space Patterson search, which is indeed not the same as
RMC, normal MC, genetic algorithms or other shuffle methods.
Mike Glazer wrote the following on 17/12/2015 12:50:
But the original question was:
What's the right nickname for the method of structure solution from
powders, which instead of analyzing electron (nuclear) density shuffles
atoms or molecules around a cell and compares experimental and calculated
patterns ?
That's what we do with RMC in practice. We use RMC to create models and
then compare with experimental patterns.
Mike
Professor A M Glazer
Department of Physics
Parks Road
Oxford
OX1 3PU
United Kingdom
Tel/Fax: 44 1865 272290
Mobile: 0778 696 0537
******************************************
Vice-President of the International Union of Crystallography
Emeritus Professor of Physics and
Emeritus Fellow of Jesus College Oxford
Visiting Professor at the University of Warwick
Crystallographer
******************************************
" Je ne te parlerai que cristaux" L. Pasteur (1850)
http://ukcatalogue.oup.com/product/9780198744306.do
-----Original Message-----
From: Radovan Cerny [mailto:radovan.ce...@unige.ch]
Sent: 17 December 2015 11:03
To: Mike Glazer <mike.gla...@physics.ox.ac.uk>; Lubomir Smrcok
<uachs...@savba.sk>; Leonid Solovyov <l_solov...@yahoo.com>
Cc: rietveld_l@ill.fr
Subject: RE: structure solution terminology
RMC covers only a part of the "Direct space methods", not for example
methods using evolution algorithms.
Radovan Cerny
Laboratoire de Cristallographie, DQMP
Universit? de Gen?ve
24, quai Ernest-Ansermet
CH-1211 Geneva 4, Switzerland
Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto :
radovan.ce...@unige.ch
URL : http://www.unige.ch/sciences/crystal/cerny/rcerny.htm
-----Message d'origine-----
De : rietveld_l-requ...@ill.fr [mailto:rietveld_l-requ...@ill.fr] De la
part de Mike Glazer Envoy? : jeudi 17 d?cembre 2015 11:49 ? : Lubomir
Smrcok; Leonid Solovyov Cc : rietveld_l@ill.fr Objet : RE: structure
solution terminology
This all sounds like Reverse MonteCarlo (RMC) modelling. We have used this
with PDF analysis.
Mike Glazer
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Please do NOT attach files to the whole list <alan.he...@neutronoptics.com>
Send commands to <lists...@ill.fr> eg: HELP as the subject with no body
text
The Rietveld_L list archive is on
http://www.mail-archive.com/rietveld_l@ill.fr/
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
--
**********************************************************************
A. van der Lee
Institut Europ?en des Membranes
CNRS - UMR 5635
Universit? de Montpellier II - Case Courrier 047
Place E. Bataillon
34095 MONTPELLIER Cedex 5 - FRANCE
Tel : 33 (0) 4 67 14 91 35
Fax : 33 (0) 4 67 14 91 19
**********************************************************************
member of RECIPROCS - R?seau des Enseignants, Chercheurs et ITA
Professionnels de la Cristallographie Structurale (French professional
crystallographer network):
http://metiersit.dsi.cnrs.fr/index.php?page=ReseauMetiers&codeBap=B
**********************************************************************
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Please do NOT attach files to the whole list <alan.he...@neutronoptics.com>
Send commands to <lists...@ill.fr> eg: HELP as the subject with no body text
The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
