Bug fix in FardalStreamDF.

[jl3937]

Describe your changes

Fix the implementation of FardalStreamDF based on https://arxiv.org/pdf/1410.1861.pdf.
Specifically, we made the changes based on Eq. (21) and Eq. (6) in the paper.

Checklist

• Did you add tests?
• Did you add documentation for your changes?
• Did you reference any relevant issues?
• Did you add a changelog entry? (see CHANGES.rst)
• Are the CI tests passing?
• Is the milestone set?

[adrn]

This is a good catch - thanks! I did have a reason for changing these values back when I implemented it, but I can't track down why. It does make sense for the class called FardalStreamDF to be true to the Fardal et al. 2015 publication, as you've fixed, but I'm worried that this will cause some backwards compatibility issues for users who were using it previously. One option would be to add an argument to the class (with a default False value) to let the user specify whether they want to use the original prescription, or the Gala augmented values? Is that something you'd be interested in implementing here?

[jl3937]

This is a good catch - thanks! I did have a reason for changing these values back when I implemented it, but I can't track down why. It does make sense for the class called FardalStreamDF to be true to the Fardal et al. 2015 publication, as you've fixed, but I'm worried that this will cause some backwards compatibility issues for users who were using it previously. One option would be to add an argument to the class (with a default False value) to let the user specify whether they want to use the original prescription, or the Gala augmented values? Is that something you'd be interested in implementing here?

Thanks for reviewing the change! It's a great idea to protect the change by a flag for backwards compatibility. But I guess you could be the better person implementing it in terms of naming, adding description and consistent code style. Just let me know. Thanks!

[adrn]

Sure -- I can take it from here. I'll just contribute to this PR, so your contribution is still tracked. Thanks again for raising this!

[jl3937]

Sure -- I can take it from here. I'll just contribute to this PR, so your contribution is still tracked. Thanks again for raising this!

Thanks for the thorough fixes!