Waterfall from existing data array + header dict combo currently broken (`setup_freqs()` missing) about blimpy

[texadactyl]

@Sofysicist

I went all the way back to blimpy version 1.3.4 (earliest release) i.e. https://github.com/UCBerkeleySETI/blimpy/tree/1.3.4
The last commit for version 1.3.4 was on Nov 29, 2018.

The _setup_freqs function referenced in the Waterfall object is an inherited function from a "Filterbank" object defined in an obsolete filterbank.py source file. When the latter was scheduled for obsolesence as part of a large reorganisation, several of its functions were moved to waterfall.py and elsewhere. It appears that _setup_freqs was left out somehow. And, it might have been left out because it didn't match what the reference in Waterfall needed (guessing). If so, that code in Waterfall should have been removed.

The current Waterfall instantiation (__init__) could use some additional diagnostic code.

So, the desired function seems to be to instantiate a new Waterfall object given a metadata (header) dict object and a complete data matrix as opposed to getting this from a file. This should be new code that is equivalent to the "if filename" section preceding it. Agree?

[texadactyl]

Anyone reading this issue should not be distracted by the _setup_freqs function that is defined in the Reader object of the blimpy/io/base_reader.py source file. Unfortunately, blimpy has some function names that are repeated at multiple levels and perform different functions.

[texadactyl]

@Sofysicist
My question about this issue still needs resolution. I want to make sure that (a) I interpreted your request correctly and (b) this proposed capability is still of interest.

[Sofysicist]

Agree with your definition of the desired function here, thanks. I actually just ran into a need for this functionality again (making a waterfall object from an existing data array and header dictionary), so it is definitely still-of-interest!

[texadactyl]

@Sofysicist

I was thinking about a simple interface to produce a blimpy Waterfall object. Inspiration came from https://github.com/UCBerkeleySETI/turboseti_stream/blob/main/turboseti_stream/doppler_finder.py, the Gnu Radio project of Summer 2021.

However, on second thought, we will go with a single Waterfall class with the existing parameters (simpler). I'll make it work with the supplied data matrix and metadata (header dict).

What are you planning to do with the Waterfall object? Plot? Save it to an .h5 file or .fil file?

[texadactyl]

@Sofysicist
Ready for testing: blimpy 2.1.1.

[texadactyl]

@Sofysicist
Reminder that blimpy 2.1.3 is ready for testing.