former expons attribute of Poly class

[davidovitch]

I was checking out the examples from jp5000/PCE-4-WindEnergy and noticed the usage of the expons attribute of Poly classes. This works for chaospy v1.0 (to be specific, at this commit: jonathf/chaospy@b6e236cbfb901e00da35866d4aa90d67fd8c4fa3, or as in this fork: jp5000/chaospy), but not for the latest version. If I understand it correctly, the exponents are now in the keys attribute and are ordered corresponding to Poly.coeffs. In chaospy v1.0 the ordering of Poly.expons and Poly.keys is different. It also seems that the ordering of chaospy v1.0 Poly.expons is different compared to the ordering of chaospy v2.0+ Poly.keys. I don't know if a certain ordering has any real practical usefulness (I am a PCE noob).

And finally my question: was expons removed and replaced by keys for a specific reason, or is this a mistake?

[jonathf]

Ah, yes. The expon included a in-place sort, which isn't allowed in python 3. I therefore changed it. I might have been a bit greedy deleting it not realisings that it was in use.

To answer your questions:

• Ordering does not matter.
• Keys used to be unordered, but for reproducability in examples etc, it is now sorted
• As a result keys replaces expons

[davidovitch]

Thanks again for a very quick and clear response :-) This issue can be closed as far as I am concerned.