but I find it strange that some PATH (I don’t recall which one) can lead to
NPARTYPEmissing error
The PATH is pointing to a newer CADET-Core version, probably a v6 pre-release or a master build. For v6 (which is not released yet, only pre-releases as described here) there will be some interface changes. Depending on the unit operation, NPARTYPE will be a mandatory field.
Per default, conda and PyPi install the latest stable release which is v5.1.X
Pre-releases can be installed via conda/PyPi as described here: CADET-Core v6 pre-releases and release strategy
Best regards,
Jan