Help in usage of cellcvrt

Alloy Theoretic Automated Toolkit (ATAT)
1

Dear Axel,

As per the flags for cellcvrt program, -gsg flag generates the space group. During CE, I would like to know the space groups (and also space group no.) of str.out and str_relax.out structures. There is of course FINDSYM program; however I would like to know if this could be done within the ATAT framework and what is the usage "cellcvrt -gsg …"?

Thank you
Suddhasattwa

2

The command cellcvrt -gsg generates a full spacegroup from a few generator specified in the file indicated by the -sg=filename.in option. So this is not what you are looking for.
The short answer (for now) is that there is no command in ATAT that will give you the space group name from a structure given as input. There are some command that get close to what you want:

cellcvrt -sym < str.in

will find the space group and write in out. However, it is only in the form of matrix operations, not the spacegroup name.

cellcvrt -ppg < str.in

will print the point group name.

fixcell -b < str.in
cellcvrt -pbv <str.in (in version 3.09 and later)

will find the bravais lattice and the setting.

wycked spacegroupnum wyckoff_positions

(e.g. wycked 176 ac ) will generate a structure template for the given symmetry information. This is the reverse of what you need.

3

Dear Axel,

I would like to convert a POSCAR file into fractional coordinates. Can I use the cellcvrt for that. I tried cellcvrt -f < POSCAR > stdout, but it writes repeatedly
-nan -nan -nan
-nan -nan -nan
-nan -nan -nan
-nan -nan -nan
-nan -nan -nan
-nan -nan -nan
end
into the file.

Am I using cellcvrt correctly?

In fact, I find it curious that from my observations runstruct command sometimes converts to fractional and sometimes into cartesian coordinates.

Regards, Siau

4

cellcvrt (and most ATAT commands) do not read the POSCAR format (I didn’t want to "favor" one code over another… and the ATAT format is quite convenient when you know it…). See help with maps -h
However, you easily convert a POSCAR to the ATAT format: If you run

runstruct_vasp -ex

in the directory containing your POSCAR, it will create a file called str_relax.out and you can then do

cellcvrt -f < str_relax.out > str_relax_f.out