[Wien] mini with constrains

[Gilles Hug]

Thanks Laurence,
In my case it is two coordinates (x and y) of the same atom which are 
linked (atom on a mirror).
Would it be it the same?
Cheers
Gilles


Le 23 mars 05, à 16:00, L. D. Marks a écrit :

> A good question, with a slightly complicated answer. If two (or more)
> atoms are linked by symmetry relationships or something else, this 
> should
> (with some caveats about numerical accuracy) also be there in the 
> forces
> and the second derivative matrix. Even though you may have N positions
> and the full matrix may be NxN variables, there will only be M 
> independent
> positions and a smaller MxM effective matrix. The time for a 
> minimization
> should therefore scale something like M**alpha where alpha is some
> nebulous parameter between 1-2.
>
> In principle one can insert a matrix variable conversion into mini to
> convert from one set of variables to another which might be useful in 
> some
> special cases, but for general problems would not be useful.
>
> On Wed, 23 Mar 2005, Gilles Hug wrote:
>
>> Ok very good so I proceed like that.
>> The real question was what happens if I have for example two of such
>> atoms?
>> Does mini search in a 4 dimensions space or in a 2 dimensions space?
>> Even though the result will always be the same the efficiency might be
>> different.
>> Cheers,
>> Gilles
>>
>
> -----------------------------------------------
> Laurence Marks
> Department of Materials Science and Engineering
> MSE Rm 2036 Cook Hall
> 2220 N Campus Drive
> Northwestern University
> Evanston, IL 60201, USA
> Tel: (847) 491-3996 Fax: (847) 491-7820
> email: L - marks @ northwestern . edu
> http://www.numis.northwestern.edu
> -----------------------------------------------
>
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>
Dr. Gilles Hug
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