sot / xija

Thermal modeling framework for Chandra X-ray Observatory
https://sot.github.io/xija
BSD 3-Clause "New" or "Revised" License
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Request documentation on Pitch Bin default values (Ps) #47

Open Gregg140 opened 6 years ago

Gregg140 commented 6 years ago

I have a general question regarding adding pitch bins in a .json file:

This is a fragment of a json file I'm working with. I want to ad a 120 degree pitch bin - which I've done in P_pitches:

................... "init_kwargs": { "P_pitches": [ 45, 60, 90, 105, 120, <- This pitch bin added 130, 150, 180 ], "Ps": [ 0.58, 0.5, 0.41, 0.7, <- Need to add value here 1.0, 0.9, 0.79 ], .................

But I also need to add a value in Ps. Best I can get from the documentation is that these are 'default values'. They seem to be less than one. Can you describe how they are used and how one would arrive at a default value when adding another pitch bin?

Thanks

taldcroft commented 6 years ago

@Gregg140 - these are the values that are used to create a XijaModel component object, e.g. when instantiating a SolarHeat class object. They typically then get updated later, hence the designation as default parameters.

Here is the relevant code that should make it more clear:

https://github.com/sot/xija/blob/b06fd65603de5e7e23b8d0a9fb411305840e98cf/xija/model.py#L128

taldcroft commented 6 years ago

A pull request to update the documentation would be most welcome! I probably can't make this a priority any time soon, so if you or ACIS does not plan on this then go ahead close this issue.