[ase-users] query on code in NeighborList [SEC=UNCLASSIFIED]

[jensj at fysik.dtu.dk]

> Hello,
>
> I have noticed a couple of odd things with the NeighborList function.
>
> 1. The documentation says this is used by the EMT potential but it
> appears to be somewhat replicated in the EMT code but not strictly used.
>
> "The EMT potential and the GPAW DFT calculator both make use of ASE’s
> built-in neighbor-list class:"

You are right - The EMT implementation in ASE doesn't use the NeighborList
as it should!  I'll take a look at that.

> 2. The code that is in NeighborList shows (what I believe is addressing
> PBC)
>
> for n1 in range(0, N[0] + 1):
>     for n2 in range(-N[1], N[1] + 1):
>         for n3 in range(-N[2], N[2] + 1):
>
> but the similar code in EMT()
>
> for i1 in range(-N1, N1 + 1):
>     for i2 in range(-N2, N2 + 1):
>         for i3 in range(-N3, N3 + 1):
>
> shows a different lower bounder for the x axis. Is the code in
> NeighborList correct ?

Yes.  It's being a bit more cleaver than the EMT implementation which will
find all neighbor pairs twice.

Jens Jørgen

> Thanks
>
> Paul White
>
> DSTO
> Melbourne, Australia
>
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