[Pw_forum] help on q2r.x error!

[shangyi]

Dear Eyvaz and Paolo:
  Thanks for your kind reply! With your advice, I get the results of interatomic force constants in real space at gamma point.> Hi,> > --- mashangyi <shang.yi at hotmail.com> wrote:> > > Dear all: I encounter a problem when I use the> > q2r.x transform the dynamical matrix of gamma point> > to interatomic force constants in real space. The> > system in my calculation is a Si-supercell composed> > of 64 Si atoms. I want to get some properties of it,> > like phdos, vibrational energy, entropy and so on.> > Following example02 and 06 indication, I calculate> > the dynamical matrix at the gamma point of the> > supercell after scf calculation( scf use 2x2x2> > k_points). When I call q2r.x to calculate IFC's in> > real space, it complains the follow> >> errors:+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++> > transforming Si-bulk.q2r.in C(q) => C(R)...forrtl:> > severe (19): invalid reference to variable in> > NAMELIST input, unit 5, file stdin, line 5, position> > There is very clean indication what is wrong: you> specified a parameter which does not exist in> NAMELIST.> > > and q2r.x input-file:> > &input fildyn = 'si-bulk.dynG' zasr = 'simple'> > flfrc = 'si-bulk.fc' nr1=2, nr2=2, nr3=2 nfile = 1> > > filin = 'si-bulk.dynG'/> > There is no keyword "filin" in NAMELIST. That is your> problem, so, remove this line.> > Besides, I did not understand you did scf-calculations> using 2x2x2 k-mesh, and then made phonon calculations.> If so, nr1=2 and etc. is not correct. > Here you have to specify q-points mesh different of> k-points used in scf-calculations. Then q2r will be> able to do FFT F(q)=>F(R). So, you should put here > nr1=1 etc. as you used only the Gamma point. Is the> use only the Gamma point is OK for FFT, some doubts. > > Probably, you have an enormous computational resource> and are very ambitious to calculate phonons for 64> atoms supercell. For ideal case these properties you> would like to calculate is just 32 times that these> for 2 atomic cell. 
;( No, I haven't enormous eomputational resource and I'm just a little novice on phonons calculation. I find the resource the phonon calculation needed is out of my expection when I first touch it. For the aim of obtaining some properties of point-defects in Si-supercell, I try to make the perfect Si-bulk as reference. And for consistency I use the same k-points, supercell and cutoffs as initial geometry optimization. The phonons calculation is so expensive that I have to just calculate the dynamical matrix at the gamma point of the supercell.
> Bests,> Eyvaz.> 
yours, shangyi
Best regards!
 Graduate school of China academy of science 
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