astropy/astropy — pull request #2177 by embray (2014-03-07 21:34:08+00:00)
Title: Fix basic SIP model functionality

Fixes the `_SIP1D` class by making it subclass `PolynomialBase` and bringing it closer in implementation to other `PolynomialBase` subclasses. Really it would be best if this subclassed `Polynomial2D`, but that will require a little refactoring of how the polynomial models work. For one, it would be nice to easily customize the parameter name format. There's a lot of other boilerplate and repetition that I think could be whittled down. But that will be an issue for another PR.

I would still like to add some tests before merging this--at the very least there should be a test to evaluate a simple SIP model that can be easily checked for correctness.