bug for negative residue numbers in charmmpsffile?

[Henry van den Bedem]

Hi:

Openmm-6.3.1 failed to read residues with negative numbers in my charmm psf file. It used to work fine in Openmm-6.2.0. I traced it back to a line

_resre = re.compile(r'(\d+)([a-zA-Z]*)')

in OpenMM-6.3.1-Linux/python/simtk/openmm/app/charmmpsffile.py

changing it to

OpenMM-6.3.1-Linux/python/simtk/openmm/app/charmmpsffile.py

seemed to have fixed the problem. Any particular reason to exclude negative residues?

Thanks!

[Henry van den Bedem]

Sorry, should have read

changing it to

_resre = re.compile(r'(-?\d+)([a-zA-Z]*)')

Thanks.

[Jason Swails]

Any particular reason to exclude negative residues?

Nope. Didn't realize PSF files used them when I wrote the parser (I use CHARMM minimally myself). I'll fix it. Thanks for the report and the fix!