[Pw_forum] dynamic matrix and symmetry

[xianghjun]

Dear giovanni:

Thank you for your comment.It helps a lot.
Best Regards.
xianghjun


Giovanni Cangiani wrote:

>Yous should look into the phonon (PH) source directory.
>The DM is symmetrized in symdynph_gq.
>Symdynph_gq is called the first time from set_irr (for full DM
>calculation) where the DM is filled with random numbers, 
>symmetrized, and diagonalized in order to find the displacement
>patterns. 
>When all modes have been computed, Symdynph_gq is called again
>on the true DM before the final diagonalization.
>
>The symmetrization consists essentially averaging over all
>rotated copies of the input DM. Where the rotations are those
>of the small group of q.
>The tricky thing is how to apply a rotation of the small group
>of q to the dynamical matrix. The way this is done in symdynph_gq
>is quite complicated but you can anyway understand the procedure
>by carefully inspecting the code. 
>
>I am not the author of the routine so it might be based on a reference
>which I am not aware of but I found quite interesting the 
>following ones:
>Maradudin, Rev. Mod. Phys. 40 p.1
>Hendrikse et. al. Computer Phys. Comm. 86 p.297
>
>	giovanni
>
>
>On Tue, 2003-04-29 at 05:55, xianghjun wrote:
>  
>
>>Dear all,
>>I have been reading the source code of pwscf 1.2.0.I don't know how
>>pwscf symmetrizes the
>>dynamic matrix using symmetry.
>>You are welcome to give me some hints or some reference.
>>Any suggestion would be appreciated.
>>
>>Best Regards.
>>xianghjun
>>
>>
>>_______________________________________________
>>Pw_forum mailing list
>>Pw_forum at pwscf.org
>>http://www.democritos.it/mailman/listinfo/pw_forum
>>    
>>
>
>_______________________________________________
>Pw_forum mailing list
>Pw_forum at pwscf.org
>http://www.democritos.it/mailman/listinfo/pw_forum
>
>
>  
>