MS are not laid out monotonically

[viralp]

Hi,

I am working on one JVLA data which has 16 spws (16 to 31). I am using Cubical's sel-ddid option as
sel-ddid: "16:" but it is giving the following error

# INFO      16:34:01 - main               [0.2 3.0 0.1Gb] Exiting with exception: RuntimeError(The selected DDID/frequencies in this MS are not laid out monotonically. This is currently not supported.)
#  Traceback (most recent call last):
#   File "/opt/venv/lib/python3.8/site-packages/cubical/main.py", line 364, in main
#     ms = MSDataHandler(GD["data"]["ms"],
#   File "/opt/venv/lib/python3.8/site-packages/cubical/data_handler/ms_data_handler.py", line 504, in __init__
#     raise RuntimeError("The selected DDID/frequencies in this MS are not laid out monotonically. This is currently not supported.")
# RuntimeError: The selected DDID/frequencies in this MS are not laid out monotonically. This is currently not supported.
# 
# 2023-08-02 16:34:01: gocubical exited with code 1

Also I tried various option sel-ddid: "16,17,18,..31", sel-ddid: "0:" but none of the option works. If I combine all spws then it is working fine with single spw. Any suggestion how to use multi spws in cubical? Thanks.

[JSKenyon]

Hi @viralp - apologies for the delay. This is a difficult one to diagnose without the measurement set in question. The VLA SPWs overlap in the middle, which is a known problem for CubiCal. See #464 for a workaround (and the syntax used there). If that still fails, can you please try and figure out how the channels are laid out in the MS? The SPECTRAL_WINDOW subtable should contain some clues.