[ase-users] incorrectly ordered lattice vectors for vasp calculator

[Offermans Willem]

I’m convinced by your argument Jens, reordering doesn’t change the intention of the user input. It just adapts to the idiosyncrasy of VASP, which ASE is doing anyway.
Sorry for the noise.


Met vriendelijke groeten,
Mit freundlichen Grüßen,


Willem Offermans
Researcher Electrocatalysis SCT
VITO NV | Boeretang 200 | 2400 Mol
Phone:+32(0)14335263 Mobile:+32(0)492182073

Willem.Offermans at Vito.be<mailto:Willem.Offermans at Vito.be>

[cid:982BA063-B96A-4A1B-89AB-5A01CA9FC70D at vito.local]

On 5 Nov 2018, at 15:42, Noam Bernstein <noam.bernstein at nrl.navy.mil<mailto:noam.bernstein at nrl.navy.mil>> wrote:

Why not reorder the vectors only when writing the POSCAR (not in the underlying ASE object)?  I think of VASP as just an energy/force/stress calculate engine.    How is reformatting the ASE data into the form that VASP wants changing user input?  I think of it as similar to doing unit conversion for a calculator that expected positions in nm.  I guess the one thing it really would break is the use of VASP’s selective dynamics from ASE, but I think that ASE’s constraints are the better way to handle that kind of requirement.

Is it really a good idea to make ASE _users_ keep track of every idiosyncrasy of every calculator?  That would make it very difficult to write scripts that are general (w.r.t. calculator), which I think is one of the great strengths of ASE.

Noam

On Nov 5, 2018, at 2:12 AM, Offermans Willem via ase-users <ase-users at listserv.fysik.dtu.dk<mailto:ase-users at listserv.fysik.dtu.dk>> wrote:

Dear ASE friends,

Changing the user input without notice is not a good idea, to my opinion.

A proposal for reorder with user confirmation request would be my idea.



Met vriendelijke groeten,
Mit freundlichen Grüßen,


Willem Offermans
Researcher Electrocatalysis SCT
VITO NV | Boeretang 200 | 2400 Mol
Phone:+32(0)14335263 Mobile:+32(0)492182073

Willem.Offermans at Vito.be<mailto:Willem.Offermans at Vito.be>

<vito.jpg>

On 5 Nov 2018, at 07:40, Jens Jørgen Mortensen via ase-users <ase-users at listserv.fysik.dtu.dk<mailto:ase-users at listserv.fysik.dtu.dk>> wrote:

On 11/1/18 4:49 PM, Noam Bernstein via ase-users wrote:
Does anyone else think that the fact that the ase vasp calculator just passes the cell vectors to vasp, without reordering them if the triple scalar product is negative, is a bug?  VASP certainly refuses to run with such a set of lattice vectors.


I think ASE should raise an exception for that case - not try to reorder lattice vectors.


Jens Jørgen




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