[xcrysden] Reg: Limit of maximum number of number of K points to plot Fermi surfaces for different structures

[Peter Blaha]

Yes, there is for sure a limit, both with the number of k-points and 
with the number of bands (eigenvalues).
The parsing of the output files is done via some auxiliary fortran programs.

You have to get also the xcrysden source code and check the fortran 
files. (I'm abroad presently and cannot check which of the fortran 
source files you have to modify, but it should be obvious from the 
name). Look into the source and increase the dimensions.
Since these are very old programs, there is no dynamic allocation in the 
code and for memory reasons the parameters were kept very small at that 
time.

Am 10.11.2016 um 13:37 schrieb Peram sreenivasa reddy:
>
> Dear XCrySDen,
>
> I am working on FCC compounds (which have four atoms in a unit cell)
> with Wien2k code. To get Fermi surface i used 44x 44x 44 K-mesh, which
> will create 2168 k points in the Brillouin Zone. With this number of K
> points, i get smooth Fermi surfaces.
>
> After this, i created a supercell which is 8 times larger than the
> initial one (which have 32 atoms). In this case, i used 10x10x10
> k-mesh(overall 1000 points) to get Fermi surface (which gave 516 k
> points). But i am getting errors while generating Fermi surfaces. If i
> do the same calculations with lesser k points it is not giving any
> errors, but my Fermi surfaces are not smooth. Please suggest me how to
> overcome this problem.
>
> Is there any maximum limit of k-points usage for different structures?
> If i want to run with high k-points what i have to do?. Means is there
> any file to edit the limit values and re-install the XCrySDen software.
>
> Please suggest a solution.
>
> Thanking you.
>
>
>
> --
> /P.V.SREENIVASA REDDY/
> /Research Scholar
> Department of Physics /
> /Indian Institute of Technology/
> /Hyderabad/
>
>
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> XCrySDen at democritos.it
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>

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