WIP: Basic multimethod fitting

[ajwheeler]

This is a rough draft of a fitting routine based on some of the ideas of Bacchus.

[github-actions]

Benchmark Results (Julia v1)

Time benchmarks

	main	97fd66b...	main / 97fd66b...
synthesis/M dwarf/100 Å of APOGEE w/ water	7.63 ± 0.016 s	7.51 ± 0.0046 s	1.02 ± 0.0022
synthesis/M dwarf/4000 Å - 8000 Å VALD solar	12.5 ± 0.017 s	12.6 ± 0.12 s	0.998 ± 0.0094
synthesis/M dwarf/APOGEE DR17 w/o water	9.69 ± 0.021 s	9.63 ± 0.018 s	1.01 ± 0.0029
synthesis/M dwarf/one wavelength	0.306 ± 0.00066 s	0.306 ± 0.00076 s	1 ± 0.0033
synthesis/sun/100 Å of APOGEE w/ water	0.866 ± 0.0021 s	0.863 ± 0.0023 s	1 ± 0.0037
synthesis/sun/4000 Å - 8000 Å VALD solar	5.92 ± 0.0065 s	5.9 ± 0.015 s	1 ± 0.0028
synthesis/sun/APOGEE DR17 w/o water	4.97 ± 0.013 s	4.94 ± 0.0076 s	1.01 ± 0.0031
synthesis/sun/one wavelength	0.129 ± 0.00039 s	0.128 ± 0.0004 s	1 ± 0.0044
time_to_load	2.81 ± 0.019 s	2.82 ± 0.019 s	0.995 ± 0.0093

Memory benchmarks

	main	97fd66b...	main / 97fd66b...
synthesis/M dwarf/100 Å of APOGEE w/ water	1.74 M allocs: 3.24 GB	1.74 M allocs: 3.24 GB	1
synthesis/M dwarf/4000 Å - 8000 Å VALD solar	8.62 M allocs: 7.11 GB	8.62 M allocs: 7.11 GB	1
synthesis/M dwarf/APOGEE DR17 w/o water	5.6 M allocs: 5.22 GB	5.6 M allocs: 5.22 GB	1
synthesis/M dwarf/one wavelength	1.15 M allocs: 0.286 GB	1.15 M allocs: 0.286 GB	1
synthesis/sun/100 Å of APOGEE w/ water	1.17 M allocs: 0.238 GB	1.17 M allocs: 0.238 GB	1
synthesis/sun/4000 Å - 8000 Å VALD solar	8.49 M allocs: 2.86 GB	8.49 M allocs: 2.86 GB	1
synthesis/sun/APOGEE DR17 w/o water	5.29 M allocs: 2.17 GB	5.29 M allocs: 2.17 GB	1
synthesis/sun/one wavelength	0.785 M allocs: 0.117 GB	0.785 M allocs: 0.117 GB	1
time_to_load	0.159 k allocs: 11.2 kB	0.159 k allocs: 11.2 kB	1

[github-actions]

TODOs and @show instances found in this PR:

src/Fit/fit_via_multimethod.jl:8:TODO
src/Fit/fit_via_multimethod.jl:9:TODO don't hardcode Fe / [m/H]
src/Fit/fit_via_multimethod.jl:10:TODO make sure solar abundances are flexible. I think they currently are.
src/Fit/fit_via_multimethod.jl-11-
src/Fit/fit_via_multimethod.jl-12-# Keyword arguments:
src/Fit/fit_via_multimethod.jl-13-
--
src/Fit/fit_via_multimethod.jl:16:# TODO kwarg everything?
src/Fit/fit_via_multimethod.jl-17-"""
src/Fit/fit_via_multimethod.jl-18-function multimethod_abundances(linelist, element, guess, lines_to_fit, obs_flux, obs_wls, R,
src/Fit/fit_via_multimethod.jl-19-                                err=ones(length(obs_flux)); verbose=true,
--
src/Fit/fit_via_multimethod.jl:21:    # TODO check no conflicting R specification
src/Fit/fit_via_multimethod.jl-22-    # check that lines_to_fit are within the range of obs_wls
src/Fit/fit_via_multimethod.jl-23-
src/Fit/fit_via_multimethod.jl:24:    # wavelengths, windows and LSF, TODO refactor
src/Fit/fit_via_multimethod.jl:25:    windows = [(l - 1, l + 1) for l in lines_to_fit] # TODO kwarg
src/Fit/fit_via_multimethod.jl-26-    merged_windows, _ = Korg.merge_bounds(windows, 0.0)
src/Fit/fit_via_multimethod.jl-27-    synthesis_wls, obs_wl_mask, LSF = Korg.Fit._setup_wavelengths_and_LSF(obs_wls,
src/Fit/fit_via_multimethod.jl-28-                                                                          nothing,
--
src/Fit/fit_via_multimethod.jl:64:    # TODO better
src/Fit/fit_via_multimethod.jl:65:    pseudocontinuum_mask = abs.(model_spectra[:, end] - model_spectra[:, 1]) .< 0.01 # TODO kwarg
src/Fit/fit_via_multimethod.jl-66-    model_pseudocontinua = [calculate_pseudocontinuum(obs_wls, m, pseudocontinuum_mask)
src/Fit/fit_via_multimethod.jl-67-                            for m in eachcol(model_spectra)]
src/Fit/fit_via_multimethod.jl-68-    model_pseudocontinua = hcat(model_pseudocontinua...)
--
src/Fit/fit_via_multimethod.jl:134:        # TODO everthing about this is terrible
src/Fit/fit_via_multimethod.jl-135-        firstind = r[1] + length(r) ÷ 2 - 2
src/Fit/fit_via_multimethod.jl-136-        lastind = firstind + 4
src/Fit/fit_via_multimethod.jl-137-        firstind = max(1, firstind)