racs-tools 4.3.1

Useful scripts for RACS.

RACS-tools

Useful scripts for RACS

Installation

Conda

The recommended way to install. First obtain conda from Anaconda or Miniconda. Clone this repo, build the environment, and activate:

git clone https://github.com/AlecThomson/RACS-tools
cd RACS-tools
conda env create
conda activate racs-tools

Docker / Singularity

NOTE: The DockerHub builds are no longer supported.

A Dockerfile is provided if you wish to build your own container. Otherwise, images are provided here on GitHub. You can pull these by running e.g.

docker pull ghcr.io/alecthomson/racstools

or

apptainer pull docker://ghcr.io/alecthomson/racstools

NOTE: These builds are still experimental, and have not been widely tested. In particular, parallelisation may not work as expected.

Pip

You can also use the package manager pip to install RACS-tools.

# Stable
pip install RACS-tools
# Latest
pip install git+https://github.com/AlecThomson/RACS-tools

Usage

$ beamcon_2D -h
usage: beamcon_2D [-h] [-p PREFIX] [-s SUFFIX] [-o OUTDIR] [--conv_mode {robust,scipy,astropy,astropy_fft}] [-v] [-d] [--bmaj BMAJ] [--bmin BMIN]
                  [--bpa BPA] [--log LOG] [--logfile LOGFILE] [-c CUTOFF] [--circularise] [-t TOLERANCE] [-e EPSILON] [-n NSAMPS] [--ncores NCORES]
                  [--executor {thread,process,mpi}]
                  infile [infile ...]

Smooth a field of 2D images to a common resolution. - Parallelisation can run using multiprocessing or MPI. - Default names of output files are
/path/to/beamlog{infile//.fits/.{SUFFIX}.fits} - By default, the smallest common beam will be automatically computed. - Optionally, you can specify a
target beam to use.

positional arguments:
  infile                Input FITS image(s) to smooth (can be a wildcard) - beam info must be in header.

options:
  -h, --help            show this help message and exit
  -p PREFIX, --prefix PREFIX
                        Add prefix to output filenames. (default: None)
  -s SUFFIX, --suffix SUFFIX
                        Add suffix to output filenames [sm]. (default: sm)
  -o OUTDIR, --outdir OUTDIR
                        Output directory of smoothed FITS image(s) [same as input file]. (default: None)
  --conv_mode {robust,scipy,astropy,astropy_fft}
                        Which method to use for convolution [robust]. 'robust' computes the analytic FT of the convolving Gaussian. Note this mode can
                        now handle NaNs in the data. Can also be 'scipy', 'astropy', or 'astropy_fft'. Note these other methods cannot cope well with
                        small convolving beams. (default: robust)
  -v, --verbosity       Increase output verbosity (default: 0)
  -d, --dryrun          Compute common beam and stop [False]. (default: False)
  --bmaj BMAJ           Target BMAJ (arcsec) to convolve to [None]. (default: None)
  --bmin BMIN           Target BMIN (arcsec) to convolve to [None]. (default: None)
  --bpa BPA             Target BPA (deg) to convolve to [None]. (default: None)
  --log LOG             Name of beamlog file. If provided, save beamlog data to a file [None - not saved]. (default: None)
  --logfile LOGFILE     Save logging output to file (default: None)
  -c CUTOFF, --cutoff CUTOFF
                        Cutoff BMAJ value (arcsec) -- Blank channels with BMAJ larger than this [None -- no limit] (default: None)
  --circularise         Circularise the final PSF -- Sets the BMIN = BMAJ, and BPA=0. (default: False)
  -t TOLERANCE, --tolerance TOLERANCE
                        tolerance for radio_beam.commonbeam. (default: 0.0001)
  -e EPSILON, --epsilon EPSILON
                        epsilon for radio_beam.commonbeam. (default: 0.0005)
  -n NSAMPS, --nsamps NSAMPS
                        nsamps for radio_beam.commonbeam. (default: 200)
  --ncores NCORES       Number of cores to use for parallelisation. If None, use all available cores. (default: None)
  --executor {thread,process,mpi}
                        Executor to use for parallelisation (default: thread)

$ beamcon_3D -h
usage: beamcon_3D [-h] [--uselogs] [--mode MODE] [--conv_mode {robust,scipy,astropy,astropy_fft}] [-v] [--logfile LOGFILE] [-d] [-p PREFIX] [-s SUFFIX]
                  [-o OUTDIR] [--bmaj BMAJ] [--bmin BMIN] [--bpa BPA] [-c CUTOFF] [--circularise] [--ref_chan {first,last,mid}] [-t TOLERANCE]
                  [-e EPSILON] [-n NSAMPS] [--ncores NCORES] [--executor_type {thread,process,mpi}]
                  infile [infile ...]

Smooth a field of 3D cubes to a common resolution. - Default names of output files are /path/to/beamlog{infile//.fits/.{SUFFIX}.fits} - By default, the
smallest common beam will be automatically computed. - Optionally, you can specify a target beam to use. - It is currently assumed that cubes will be
4D with a dummy Stokes axis. - Iterating over Stokes axis is not yet supported.

positional arguments:
  infile                Input FITS image(s) to smooth (can be a wildcard) - CASA beamtable will be used if present i.e. if CASAMBM = T - Otherwise beam
                        info must be in co-located beamlog files. - beamlog must have the name /path/to/beamlog{infile//.fits/.txt}

options:
  -h, --help            show this help message and exit
  --uselogs             Get convolving information from previous run [False]. (default: False)
  --mode MODE           Common resolution mode [natural]. natural -- allow frequency variation. total -- smooth all plans to a common resolution.
                        (default: natural)
  --conv_mode {robust,scipy,astropy,astropy_fft}
                        Which method to use for convolution [robust]. 'robust' computes the analytic FT of the convolving Gaussian. Note this mode can
                        now handle NaNs in the data. Can also be 'scipy', 'astropy', or 'astropy_fft'. Note these other methods cannot cope well with
                        small convolving beams. (default: robust)
  -v, --verbosity       Increase output verbosity (default: 0)
  --logfile LOGFILE     Save logging output to file (default: None)
  -d, --dryrun          Compute common beam and stop. (default: False)
  -p PREFIX, --prefix PREFIX
                        Add prefix to output filenames. (default: None)
  -s SUFFIX, --suffix SUFFIX
                        Add suffix to output filenames [{MODE}]. (default: None)
  -o OUTDIR, --outdir OUTDIR
                        Output directory of smoothed FITS image(s) [None - same as input]. (default: None)
  --bmaj BMAJ           BMAJ to convolve to [max BMAJ from given image(s)]. (default: None)
  --bmin BMIN           BMIN to convolve to [max BMAJ from given image(s)]. (default: None)
  --bpa BPA             BPA to convolve to [0]. (default: None)
  -c CUTOFF, --cutoff CUTOFF
                        Cutoff BMAJ value (arcsec) -- Blank channels with BMAJ larger than this [None -- no limit] (default: None)
  --circularise         Circularise the final PSF -- Sets the BMIN = BMAJ, and BPA=0. (default: False)
  --ref_chan {first,last,mid}
                        Reference psf for header [None]. first -- use psf for first frequency channel. last -- use psf for the last frequency channel.
                        mid -- use psf for the centre frequency channel. Will use the CRPIX channel if not set. (default: None)
  -t TOLERANCE, --tolerance TOLERANCE
                        tolerance for radio_beam.commonbeam. (default: 0.0001)
  -e EPSILON, --epsilon EPSILON
                        epsilon for radio_beam.commonbeam. (default: 0.0005)
  -n NSAMPS, --nsamps NSAMPS
                        nsamps for radio_beam.commonbeam. (default: 200)
  --ncores NCORES       Number of cores to use for parallelisation. If None, use all available cores. (default: None)
  --executor_type {thread,process,mpi}
                        Executor type for parallelisation. (default: thread)

$ getnoise_list -h
usage: getnoise_list [-h] [-s] [-b] [-c CLIPLEV] [-i ITERATE] [-f FILE] qfile ufile

 Find bad channels by checking statistics of each channel image.

positional arguments:
  qfile                 Stokes Q fits file
  ufile                 Stokes U fits file

options:
  -h, --help            show this help message and exit
  -s, --save_noise      Save noise values to disk [default False]
  -b, --blank           Blank bad channels? [default False - just print out bad channels]
  -c CLIPLEV, --cliplev CLIPLEV
                        Clip level in sigma, make this number lower to be more aggressive [default 5]
  -i ITERATE, --iterate ITERATE
                        Iterate flagging check N times [dafult 1 -- one pass only]
  -f FILE, --file FILE  Filename to write bad channel indices to file [None --  do not write]

If finding a common beam fails, try tweaking the tolerance, epsilon, and nsamps parameters. See radio-beam for more details.

Performance

Profiling for beamcon_3D suggests this program requires a minimum of ~15X the memory of a data cube slice per process to perform convolution to a common beam. So for a 800 MB slice (e.g. typical POSSUM cube) you would want to allow 15 GB memory per worker (I use 20 GB). Choose ncores appropriately given your machine memory availability and this limit to ensure optimal performance with multiprocessing.

An example slurm header for beamcon_3D:

#SBATCH --nodes=1
#SBATCH --ntasks-per-node=1
#SBATCH --cpus-per-task=<ncores>
#SBATCH --mem-per-cpu=20G

Contributing

Pull requests are welcome. For major changes, please open an issue first to discuss what you would like to change.

License

BSD-3-Clause