propagate funcdefs to Parameters in model.loads

[cassberk]

Description

From ISSUE # #931

Using the dumps and loads methods on the ModelResult class does not properly take into account loading user added functional parameter expressions. The funcdefs keyword in loads enables users to pass functions to add to the the asteval interpreter, but these are not subsequently passed into Parameters() where they are actually added to the asteval symtable. This caused deserialization to not work with ModelResults that have parameters with user defined functions as expressions.

Type of Changes

• [ x] Bug fix
• New feature
• Refactoring / maintenance
• Documentation / examples

Tested on

Python: 3.9.7 (default, Oct 15 2021, 14:20:07)
[Clang 13.0.0 (clang-1300.0.29.3)]

lmfit: 1.2.2, scipy: 1.11.1, numpy: 1.23.5,asteval: 0.9.31, uncertainties: 3.1.7

Verification

Have you

• [x ] included docstrings that follow PEP 257?

• [ x] referenced existing Issue and/or provided relevant link to mailing list?

• [ x] verified that existing tests pass locally?

• [x ] verified that the documentation builds locally?

• [ x] squashed/minimized your commits and written descriptive commit messages?

• [ x] added or updated existing tests to cover the changes?
• updated the documentation and/or added an entry to the release notes (doc/whatsnew.rst)?
• added an example? N/A

[newville]

@cassberk Thanks - I think this might be the right solution, but as said in #931, I think I want to spend a little time investigating the history of this... I feel like I am forgetting something.

Not ignoring, but sort of want to be a bit cautious...

[cassberk]

This may not be the most elegant means to do this, but something I noticed was that if the model function is not removed from the funcdefs argument, it gets added to the _asteval.symtable. Although a small change, undesired changes to the objects through de/serialization should be minimized, so I think it should be handled somehow. I added an assert to the test to ensure that the symtables are the same.

[newville]

@cassberk thanks -- I'm hoping to get to this before the end of the year/

[newville]

@cassberk thanks -- I am going to merge this for the test of the doc fix. But, I think I have a better fix for the actual code that I will try to add shortly....