How to check missing parameters before create_interchange? about openff-interchange HOT 2 CLOSED

Thank you for your response.
In my case, the ERROR catch looks good!

from openff-interchange.

You've pretty much found the API points that I would recommend¹; under the hood, ForceField.label_molecules pretty much does the same stuff as creating an Interchange object (namely filling out the the collection classes). This can be simple or tricky depending on the level of granularity you're after

• Rough pass: just see if the element(s) are in the force field at all
• Slightly more detailed pass: wrap your second code block into a function and error out in some particular cases`
  • This doesn't work for all parameter handlers; for example, throwing an error if len(matches['Bonds']) < topology.n_bonds is probably good, but the same logic for improper torsions would not work.
  • The logic within Interchange is around here
• Depending on the application, it might be easiest to just go Grace Hopper style and ask for forgiveness instead of permission

try:
    force_field.create_interchange(...)
# there are a few different exceptions that can be thrown here - this base class captures if bond/angle/torsion parameters are missing
except (UnassignedValenceParameterException, ...):
    # deal with it here - log, re-raise exception, etc.

In the case of molecular iodine, it seems like the thrown error is pretty much getting what you're asking for. Are there other cases that are tricker to deal with?

from openff-interchange.