AVICA: Automated VLBI pipeline in CASA

AVICA: Automated VLBI pipeline in CASA#

AVICA is a Python package for automated calibration of Very Long Baseline Interferometry (VLBI) data in CASA. It provides tools to ingest, manipulate, and calibrate FITS-IDI and Measurement Set files containing raw visibilities.

Installation#

Requirements:

  • Ubuntu 18.04+, Debian 10+, or RHEL/CentOS 8+

  • Python >= 3.9

The avica package is available on PyPI. Use uv or pipx for an isolated command-line installation.

Using uv:

uv tool install avica --python 3.11

Using pipx:

pipx install avica

Using pip:

pip install avica

Note

If you install with pip, use a virtual environment unless you already manage Python packages another way.

Setup#

The pipeline calibration steps rely on rPicard. Follow the rPicard setup instructions first. After rPicard is configured, AVICA only needs a minimal configuration file to get started.

Configuration#

The pipeline configuration is a plain-text key=value file. By default, AVICA looks for avica.inp in the current working directory.

Pass a custom configuration file with --configfile:

avica pipe run --configfile <path/to/config/file>

Minimal configuration:

# required
# folder_for_fits is a folder containing the raw visibility FITS files.
# casadir is the path to the monolithic CASA installation used for CASA tasks.

folder_for_fits           =   /path/to/source/folder/with/raw/visibility/fitsfiles
casadir                   =   "path/to/monolithic-casa/casa-6.x.x-xx-py3.xx.xxx/"

# optional-1
# picard_input_template the folder containing the rPicard input file.
# target_dir is where pipeline output will be saved.
# accor_solint is the number of solint partitions to use.

target_dir                =   "reductions"
picard_input_template     =   "path/to/rpicard"
accor_solint              =   4
mpi_cores_rpicard         =   10
mpi_cores_snrating        =   5
mpi_cores_importfitsidi   =   5
hi_freq_ref               =   11
snr_threshold_phref       =   7
flux_threshold_phref      =   0.15
min_channel_flagging      =   32
n_calib                   =  5
n_refant                  =  4
minsnr                    =  3.2

apply_flag_from_idi       =   True
size_limit                =   2000.0

# EXPERIMENTAL -------------------------
# configure google sheet
sheet_url                 =   None
worksheet                 =   None

# configure below if using CSV or google sheet to save all the result in a common sheet.
primary_colname           =   TARGET_NAME
primary_value             =   None
filename_col              =   FILENAMES
targetname_col            =   TARGET_NAME

# sheet configurations
working_col               =   None
working_col_only          =   False
do_pcol_validation        =   False

sci_solints               =   manual
solint_max_scan_partitions=   8
use_casadir_pythonpath    =   False
separation_thres          =   850.0
source_extract_multi_fitsfiles    =   False

To store defaults persistently in ~/.avica/avica.inp, pass an existing configuration file:

avica pipe config --default --inpfile <path/to/avica.inp>

You can also set default values directly:

avica pipe config --default key=value key2=value2 key3=value3

To set global defaults in AVICA’s installed directory, use --global in the same way:

avica pipe config --global --inpfile <path/to/avica.inp>
avica pipe config --global key=value key2=value2 key3=value3

Usage#

Run the default pipeline from the terminal:

avica pipe run --target <target-name> --fitsfilenames <file1.uvfits,file2.uvfits>

Run selected steps by passing step names:

avica pipe run preprocess_fitsidi fits_to_ms --fitsfilenames <file.uvfits>

The default pipeline executes these steps:

  • preprocess_fitsidi

  • fits_to_ms

  • avica_avg

  • avicameta_ms

  • avica_snr

  • avica_fill_input

  • avica_split_ms

  • rpicard

Common options:

Option

Description

--f, --fitsfilenames

Comma-separated FITS-IDI file names.

--t, --target

Selected field or source name.

--configfile

Configuration file containing key=value entries. Defaults to avica.inp.

--help

Show the full command help.

Output Layout#

The output folder structure follows this convention:

CWD/
|-- avica.inp
`-- reductions/
    `-- PROJECT_CODE/
        `-- wd/
            `-- wd_{BAND}/
                `-- wd_{BAND}_{TARGET_NAME}/

More Documentation#

See the dedicated pages for deeper usage notes and API reference:

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