How to downcast a TabulatedFunction class to a Continuos2DFunction class in Python?

[Xinqiang Ding]

Several Custom*Forces have the method getTabulatedFunction(). The method getTabulatedFunction returns an TabulatedFunction object. How can we call setFunctionParameters() on the returned TabulatedFunction object in Python? The TabulatedFunction class is a generic class and does not have the method setFunctionParameters(). Therefore, it has to be downcasted into the derived class Continuous2DFunction.

Thanks,
Xinqiang

[Peter Eastman]

That's a bug. It ought to return the correct subclass. It looks like the Python wrapper isn't handling that correctly. I'll see if I can fix it.

As a workaround, can you hold on to the original Continuous2DFunction object that you added to the force?

Peter

[Xinqiang Ding]

Yes. The workaround works. Thanks!
Xinqiang

[Peter Eastman]

I just posted a pull request with the fix: https://github.com/pandegroup/openmm/pull/1891

Peter