--iter-baseline does not work

[bennahugo]

    --iter-baseline does not work

$ shadems --xaxis FREQ --yaxis DATA:amp --corr YY --iter-baseline bpcal-av-noflags.ms/
2022-10-05 16:20:33 - shadems - INFO - using colourmap colorcet.bkr
2022-10-05 16:20:33 - shadems - INFO - using colourmap cmasher.pride
2022-10-05 16:20:33 - shadems - INFO - using colourmap colorcet.glasbey_dark
2022-10-05 16:20:33 - shadems - INFO - /scratch2/sharmila/venv-shadems/bin/shadems --xaxis FREQ --yaxis DATA:amp --corr YY --iter-baseline bpcal-av-noflags.ms/
2022-10-05 16:20:33 - shadems - INFO - ------------------------------------------------------
2022-10-05 16:20:33 - shadems - INFO - : MS bpcal-av-noflags.ms contains 1830 rows
2022-10-05 16:20:33 - shadems - INFO - : (1, 32768) spectral windows and channels
2022-10-05 16:20:33 - shadems - INFO - : 1 fields: J1939-6342
2022-10-05 16:20:33 - shadems - INFO - : 1 scans: 1
2022-10-05 16:20:33 - shadems - INFO - : 60/60 antennas: 0:m000 1:m001 2:m002 3:m003 4:m004 5:m005 6:m006 7:m007 8:m008 9:m009 10:m010 11:m011 12:m012 13:m013 14:m014 15:m015 16:m016 17:m017 18:m018 19:m019 20:m020 21:m021 22:m022 23:m023 24:m024 25:m025 26:m026 27:m030 28:m031 29:m032 30:m033 31:m034 32:m035 33:m036 34:m037 35:m038 36:m039 37:m040 38:m041 39:m042 40:m043 41:m044 42:m045 43:m046 44:m047 45:m048 46:m049 47:m050 48:m051 49:m052 50:m053 51:m054 52:m055 53:m057 54:m058 55:m059 56:m060 57:m061 58:m062 59:m063
2022-10-05 16:20:33 - shadems - INFO - : 1830/1830 baselines present
2022-10-05 16:20:33 - shadems - INFO - : corrs/Stokes XX YY I Q
2022-10-05 16:20:33 - shadems - INFO - ------------------------------------------------------
2022-10-05 16:20:33 - shadems - INFO - : Data selected for plotting:
2022-10-05 16:20:33 - shadems - INFO - Antenna(s) : all
2022-10-05 16:20:33 - shadems - INFO - Baseline(s) : all except autocorrelations
2022-10-05 16:20:33 - shadems - INFO - Field(s) : all
2022-10-05 16:20:33 - shadems - INFO - SPW(s) : all
2022-10-05 16:20:33 - shadems - INFO - Scan(s) : all
2022-10-05 16:20:33 - shadems - INFO - Channels : all
2022-10-05 16:20:33 - shadems - INFO - Corr/Stokes : YY
2022-10-05 16:20:33 - shadems - INFO - ------------------------------------------------------
2022-10-05 16:20:33 - shadems - INFO - loading minmax cache from bpcal-av-noflags-minmax-cache.json
2022-10-05 16:20:33 - shadems - INFO - axis: FREQ, range (None, None), discretization None
2022-10-05 16:20:33 - shadems - INFO - axis: amp(DATA), corr None, range (None, None), discretization None
2022-10-05 16:20:33 - shadems - INFO - : you have asked for 1 plots employing 2 unique datums
2022-10-05 16:20:43 - shadems - INFO - : Indexing MS and building dataframes (1770 rows, chunk size is 5000)
Traceback (most recent call last):
File "/scratch2/sharmila/venv-shadems/bin/shadems", line 8, in
main.main([a for a in sys.argv[1:]])
File "/scratch2/sharmila/venv-shadems/lib/python3.8/site-packages/shade_ms/main.py", line 419, in main
data_plots.get_plot_data(ms, group_cols, mytaql, ms.chan_freqs,
File "/scratch2/sharmila/venv-shadems/lib/python3.8/site-packages/shade_ms/data_plots.py", line 155, in get_plot_data
a1 = da.minimum(group.ANTENNA1.data, group.ANTENNA2.data)
AttributeError: 'int' object has no attribute 'data'

Originally posted by @SharmilaGoedhart in #104 (comment)

[bennahugo]

Think this is now working

4 - shadems - INFO - axis: FREQ, range (None, None), discretization None
2022-10-05 17:27:44 - shadems - INFO - axis: amp(DATA), corr None, range (None, None), discretization None
2022-10-05 17:27:44 - shadems - INFO -                  : you have asked for 1 plots employing 2 unique datums
2022-10-05 17:27:44 - shadems - INFO - : Indexing MS and building dataframes (3237 rows, chunk size is 5000)
2022-10-05 17:27:44 - shadems - INFO - : complete
2022-10-05 17:27:44 - shadems - INFO - : rendering 3 dataframes with 7.7e+05 points into 1 plot types
2022-10-05 17:27:44 - shadems - INFO - : rendering plot-DEEP_2.1491291289.1ghz.1.1ghz.4hrs.1gc-m000_m002_m005-m000-m002-DATA-XX-YY-amp-FREQ.png
2022-10-05 17:27:44 - shadems - INFO - : scanning axis min/max for DATA_amp_None
2022-10-05 17:27:45 - shadems - INFO -                  : wrote plot-DEEP_2.1491291289.1ghz.1.1ghz.4hrs.1gc-m000_m002_m005-m000-m002-DATA-XX-YY-amp-FREQ.png
2022-10-05 17:27:45 - shadems - INFO - : rendering plot-DEEP_2.1491291289.1ghz.1.1ghz.4hrs.1gc-m000_m002_m005-m000-m005-DATA-XX-YY-amp-FREQ.png
2022-10-05 17:27:45 - shadems - INFO - : scanning axis min/max for DATA_amp_None
2022-10-05 17:27:46 - shadems - INFO -                  : wrote plot-DEEP_2.1491291289.1ghz.1.1ghz.4hrs.1gc-m000_m002_m005-m000-m005-DATA-XX-YY-amp-FREQ.png
2022-10-05 17:27:46 - shadems - INFO - : rendering plot-DEEP_2.1491291289.1ghz.1.1ghz.4hrs.1gc-m000_m002_m005-m002-m005-DATA-XX-YY-amp-FREQ.png
2022-10-05 17:27:46 - shadems - INFO - : scanning axis min/max for DATA_amp_None
2022-10-05 17:27:47 - shadems - INFO -                  : wrote plot-DEEP_2.1491291289.1ghz.1.1ghz.4hrs.1gc-m000_m002_m005-m002-m005-DATA-XX-YY-amp-FREQ.png
2022-10-05 17:27:47 - shadems - INFO - Total time       : 3.16 seconds
2022-10-05 17:27:47 - shadems - INFO - Saved minmax cache to DEEP_2.1491291289.1ghz.1.1ghz.4hrs.1gc-minmax-cache.json (disable with --no-lim-save)
2022-10-05 17:27:47 - shadems - INFO - Finished
2022-10-05 17:27:47 - shadems - INFO - ------------------------------------------------------