Cliff Hansen

@miettal thanks for pointing out this shortcoming in the documentation. I think we can add text to each function's docstring. The `racking_model` keyword for `pvlib.pvsystem.PVSystem` doesn't provide much explanation either,...

@belagoof I hope we didn't miss something. I haven't seen a pull request on this issue. I favor # 2.

Thanks @belagoof, I think we dropped the ball on this one.

> That being said though, to test this new code, I would need access to snow depth not just SnowfallCentimeters. I am guessing this check wouldn't work if you don't...

A communication with the model author T. Townsend: "the pile of snow was modeled as a triangle atop a rectangle, with yes, a vertical wall on the "north" side of...

Confirmed bug. Thanks @lucasschn. The `PVSystem.get_irradiance` method is a convenience wrapper for `irradiance.get_total_irradiance` which is common front end for the set of sky diffuse models, some of which require `dni_extra`....

How about ``` if dni_extra is None: try: dni_extra = irradiance.get_extra_radiation(solar_zenith.index) except AttributeError: raise ValueError('If dni_extra is None then solar_zenith must be a Series.') ``` My hesitation is that AttributeError...

> You could perhaps just use the solar constant as `dni_extra` when all else fails. Then you don't need to raise anything. That's a good idea. Variance is at most...

`ivtools.sdm.fit_desoto_sandia` returns the product of diode factor, number of cells in series and thermal voltage per cell (termed `'a_ref'`) so that the output of this function are the parameters expected...

> Can you tell which IV curve is failing that regression step (it's done once for each IV curve). It's index 159. There's several instances where the IV data are...