[Wien] a doubt from threads in case.InM

Peter Blaha pblaha at theochem.tuwien.ac.at
Fri Aug 4 09:22:24 CEST 2017


It is NOT a divisor ! (does not make sense here). Depending on the 
method the 4th value is not used or is eg. a friction term for damped 
newton dynamics.

On 08/04/2017 02:26 AM, Gavin Abo wrote:
> Currently too lazy to check, are the data values x y z div (where div is
> the divisor)?
>
> So (x y z)/div:
>
> 0.0. 0.0 0.0 0.0 => (0, 0, 0)/0 = undefined [1] <- If it is not giving a
> divide by zero error [2], it sounds like the code is able to handle it
> and may be setting any of these divisions to 0.
>
> 0.0. 0.0 0.0 1.0 => (0, 0, 0)/1 = (0, 0, 0) <- This may be safer to use.
>
> [1] https://en.wikipedia.org/wiki/Division_by_zero
>
> [2]
> https://software.intel.com/en-us/forums/intel-fortran-compiler-for-linux-and-mac-os-x/topic/392791
>
> On 8/3/2017 9:26 AM, fatima DFT wrote:
>> Thank you very much Sir.
>> I feel relax now.
>> I did a heavy calculation using 0.0. 0.0 0.0 0.0 instead of 0.0. 0.0
>> 0.0 1.0
>>
>> So I was worried to repeat the calculation by fixing the position with
>> 0.0. 0.0 0.0 1.0.
>>
>> On Thu, Aug 3, 2017 at 8:31 PM, Laurence Marks
>> <L-marks at northwestern.edu <mailto:L-marks at northwestern.edu>> wrote:
>>
>>     Inlined
>>
>>     On Thu, Aug 3, 2017 at 9:49 AM, fatima DFT <fatimadft5 at gmail.com
>>     <mailto:fatimadft5 at gmail.com>> wrote:
>>
>>         Dear Prof. Peter, Oleg and Marks,
>>
>>         I have two queries for case.inM
>>
>>         First:
>>
>>         I stuck on case.inM file where I want to fix the positions of
>>         the heavier atom for which I do not want to relax the structure.
>>
>>
>>     A comment: fixing atoms does not do what people think, in general
>>     it does not make the convergence of QM methods faster (it can for
>>     CG). The convergence depends upon the number and density of the
>>     elastic eigenvectors  (PORT) and the elastic-electronic system
>>     (MSR1a).
>>
>>
>>         In one thread Prof Peter
>>         <https://urldefense.proofpoint.com/v2/url?u=http-3A__www.mail-2Darchive.com_wien-40zeus.theochem.tuwien.ac.at_msg03285.html&d=DwMFaQ&c=yHlS04HhBraes5BQ9ueu5zKhE7rtNXt_d012z2PA6ws&r=U_T4PL6jwANfAy4rnxTj8IUxm818jnvqKFdqWLwmqg0&m=lMntW40NGNoDrUMHYVU-vXvlVw2pGHikT4XpBt9gMhU&s=-6101yYtzjIzQWcsyC0Zc5AQTUAs08Rf0kz5Ifefu7I&e=>
>>         mentioned keeping 0 0 0 0 in the respective row of atom that I
>>         want to constrain. But this four zeros means the entire line
>>         should be zero
>>
>>         0.0 0.0 0.0 0.0   #Atom    1 Generated by pairhess   >>> Say
>>         it is for La atom.
>>
>>         As per Prof Marks
>>         <https://urldefense.proofpoint.com/v2/url?u=http-3A__www.mail-2Darchive.com_wien-40zeus.theochem.tuwien.ac.at_msg12403.html&d=DwMFaQ&c=yHlS04HhBraes5BQ9ueu5zKhE7rtNXt_d012z2PA6ws&r=U_T4PL6jwANfAy4rnxTj8IUxm818jnvqKFdqWLwmqg0&m=lMntW40NGNoDrUMHYVU-vXvlVw2pGHikT4XpBt9gMhU&s=0fcEvAFHmpT7ZahxBQYrqD0Xr0DEsgKPFE0Nk-fLeLM&e=>and
>>         Prof. Oleg
>>         <https://urldefense.proofpoint.com/v2/url?u=http-3A__www.mail-2Darchive.com_wien-40zeus.theochem.tuwien.ac.at_msg01858.html&d=DwMFaQ&c=yHlS04HhBraes5BQ9ueu5zKhE7rtNXt_d012z2PA6ws&r=U_T4PL6jwANfAy4rnxTj8IUxm818jnvqKFdqWLwmqg0&m=lMntW40NGNoDrUMHYVU-vXvlVw2pGHikT4XpBt9gMhU&s=GJxC2Mi9-Fts6rULojSPz0X_acMQL2Oe5Ie7WXILcr0&e=>
>>
>>         The only first three number should be zero
>>
>>         0.0 0.0 0.0 1.0   #Atom    1 Generated by pairhess
>>
>>         Could you please clear my doubt that:
>>
>>         How the results will differ if I will use "0.0 0.0 0.0 0.0
>>         #Atom    1 Generated by pairhess" instead of 0.0 0.0 0.0 1.0 ?
>>
>>
>>     I am 99% confident that they are equivalent.
>>
>>
>>         Second:
>>
>>         If I use "x pairhess" to generate the case.inM then does it
>>         copy the case.inM according to the structure files? I just
>>         tested it for two different structures and I saw two different
>>         kind of case.inM.
>>
>>
>>     Yes, different structures with different symmetries have different
>>     symmetry constrained sites so different case.inM.
>>
>>
>>
>>         Thank you in advance
>>
>>         regards
>>         Fatima
>>
>>
>>
>>
>>     --
>>     Professor Laurence Marks
>>     "Research is to see what everybody else has seen, and to think
>>     what nobody else has thought", Albert Szent-Gyorgi
>>     www.numis.northwestern.edu
>>     <http://www.numis.northwestern.edu> ; Corrosion in 4D:
>>     MURI4D.numis.northwestern.edu <http://MURI4D.numis.northwestern.edu>
>>     Partner of the CFW 100% program for gender
>>     equity, www.cfw.org/100-percent <http://www.cfw.org/100-percent>
>>     Co-Editor, Acta Cryst A
>>
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-- 

                                       P.Blaha
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