[Wien] error in init phonon lapw calculations with 3x3x3 supercell

[Peter Blaha]

a) You cannot run supercells with 216 atoms on a single PIV with 2 GB 
memory.
b) rkmax=3.7 would give a very bad calculation
c) you don't need 2 k-point for such large supercells.
d) Unless you are searching for some particular feature in the 
phonon-dispersion, you don't need such large supercells for phonons! It is much 
more important that you use a good RKMAX to get good forces.

> Hello Wien users,
> I am working with a SiC supercell (3 X 3 X 3)constructed with 'Phonon'. After I transferred the .d45 file to Wien and ran init_phonon_lapw I get an error message after dstart that says 
> 
> fortrl : severe (41): insufficient virtual memory.
> 
> The super cell has 216 atoms. 
> RMT*Kmax = 3.7; 
> RMT =1.76; 
> k points =2
> plane waves generated = 711879.
> My system is P IV,  has 2GB RAM and a swap space of 5000 MB. Stack size unlimit has also been done.
> Calculations with a smaller supercell (2 X 2 X 2) works fine.
> Any suggestions on how to resolve this problem will be most appreciated.
> Thank you for your help.
> Chandrika
> 


                                      P.Blaha
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Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
Phone: +43-1-58801-15671             FAX: +43-1-58801-15698
Email: blaha at theochem.tuwien.ac.at    WWW: http://info.tuwien.ac.at/theochem/
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