Indices found by ovito.data.CutoffNeighborFinder look like overflow?

OVITO
1

Here is a minimal error case. What am I doing wrong?

Pastebin for input b/c I cannot attach a file: ccfn2422-900K-40A.mdmc.sro.out - Pastebin.com

ahengst@EN4232825UL:~/.../02-mc-swap$ python3
Python 3.10.12 (main, Nov  6 2024, 20:22:13) [GCC 11.4.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import ovito
>>> data = ovito.io.import_file('ccfn2422-900K-40A.mdmc.sro.out').compute()
>>> finder = ovito.data.CutoffNeighborFinder(3.0, data)
>>> neighbors = list(finder.find(1))
>>> print([n.index for n in neighbors])
[18446744073709551615, 18446744073709551615, 18446744073709551615, 18446744073709551615, 18446744073709551615, 18446744073709551615, 18446744073709551615, 18446744073709551615, 18446744073709551615, 18446744073709551615, 18446744073709551615, 18446744073709551615]
2

You should directly iterate the finder to get the neighbors:

>>> print([n.index for n in finder.find(1)])
[0, 1484, 1485, 1650, 3, 2, 182, 181, 1486, 10, 6, 188]
3

The error is caused by an internal optimization in OVITO, where the object returned by finder.find() is reused. As a result, storing these return values for later use is invalid.

The next OVITO version will raise an error to prevent this usage.