[Pw_forum] Plotting phonon dispersion

[Vahid Askarpour]

1. You could use the ibrav=0 results. In the matdyn.in, do not use

gG 50
 X 50
 M 50
 gG 8

Instead, explicitly give the coordinates of each high-symmetry point in cartesian.

2. Four days sounds like a long time unless you are running on few nodes. If a run takes several days, you can break it up into several parts using start_q and last_q.

3. I am not sure if specifying the high-symmetry points by just using their labels in matdyn.in will work for ibrav=6. It might.

Cheers,

Vahid



> On Feb 19, 2018, at 2:27 PM, elchatz at auth.gr wrote:
> 
> 
> Ok, I am confused again.
> 
> I used ibrav=0 in the scf run that eventually gave me the error in matdyn.x.
> 
> I am running it again. This time I've used,
> 
> -----------------
> ibrav = 6,
> celldm(1) = [..]
> celldm(3) = [..]
> ------------------
> 
> in the scf. It's good to know if this is more possible to work as ph.x  
> takes about 4 days.
> 
> 
> Eleni
> 
> 
> 
> Quoting Lorenzo Paulatto <paulatz at gmail.com>:
> 
>> On 02/19/2018 03:14 PM, Saif Ullah wrote:
>>> Dear Eleni,
>>> 
>>> Did you use ibrav=0? If so, then you need to use q_in_band_form=.false.
>>> q_in_cryst_coord=.true.
>>> 
>> Neither of these two bits of advice is correct:
>> 
>> 1. q_in_band_form can be used with ibrav=0 as usual, and works just as
>> well as long as you specify the point coordinates
>> 2. there is no specific reason to use crystal coordinates with ibrav=0,
>> you can, as usual, but by no mean you "need to"
>> 
>> 
>> kind regards
>> 
>> 
>> --
>> Lorenzo Paulatto - Paris
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> 
> 
> 
> -- 
> Dr. Eleni Chatzikyriakou
> Computational Physics lab
> Aristotle University of Thessaloniki
> elchatz at auth.gr - tel:+30 2310 998109
> 
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