Error message extraction

[kjh-giesbertz]

Is your feature request related to a problem? Please describe.
In case a calculation fails, it is nice to know why without spitting yourself through the output files.

Describe the solution you'd like
It would be nice to have a method (error_message()?) which returns an error message, in the output module in case output.terminated_normally() returns False. Upon success this would just be an empty string, None would also do but not needed.

Describe alternatives you've considered

• Instead of a separate routine this could also be a field in an overloaded terminated_normally(errmsg: str) routine, but I think that is less clean.
• Using the grepper to spit myself through the output, but that is only a work-around in my opinion.

[haneug]

Thank you for raising this issue.

I think it relates to #80. Since ORCA does not return a clear error code, we need a collection of known strings to grep from the .out file. My suggestion is to maintain one central file with all relevant patterns and to implement error_message() as you suggested, returning None on success, a descriptive string if a known error pattern is found, or "unknown" if the calculation failed but no matching pattern was found.

Would this be an adequate solution to your issue?

[kjh-giesbertz]

Yes, indeed. #80 looks very related. I guess the difference is that I would like opi to take fully take care of it.

Your solution sounds perfect to me.

[haneug]

I started working on an initial implementation of output.error_message in #222 and included the following errors:

1. Input errors like unknown/duplicate simple keyword, unknown block, unknown block key, unknown block value
2. Convergence issues: SCF, geometry optimization, CP-SCF, CC
3. Memory issues: Not enough memory in the SCF, MP2 and CC.

With these I would cover some of the most typical ORCA errors. @kjh-giesbertz are there any specific errors you would like to see covered? Something you run into often?