Pyralysis

PYthon Radio Astronomy anaLYSis and Image Synthesis

Regularized image reconstruction for radio interferometry — simulate an array, state χ² + regularizers, reconstruct on CPU or GPU. Not a black-box CLEAN.

Pyralysis is a Python library (Dask, optional CuPy) for simulation, gridding, and image reconstruction. You compose the objective; there is no hidden imager. Guides: Read the Docs.

You can

Simulate an observation

VLA, ALMA, or a custom antenna config; parametric or FITS sky models; thermal noise and gain injectors.

ALMA Band 6 (230 GHz) Cycle 9.8: Rayleigh–Jeans disk (core + four rings) and three compact sources — sky, uv coverage, visibility amplitudes.

Simulation · examples/scripts/simulation_components.py

Make a dirty map and PSF

Natural, uniform, or robust weights, then a dirty image and dirty beam.

Visibility weights · Gridding · examples/scripts/dirtymapper_components.py

Reconstruct a model

State χ² plus L1, TSV, or other regularizers; solve with FISTA, L-BFGS, or SDMM. The figures below are FISTA on χ² + L1 from zeros, natural weights.

Dirty image → FISTA model (Jy/pixel) → residual. Same ALMA disk simulation as above.

Iterates from a zero start.

Regenerate the gallery with python docs/scripts/generate_readme_figures.py. Optimization · FISTA · examples/scripts/optimization_components.py

Image with closures, on GPU, or on a cluster

Closure-phase / closure-amplitude terms; the same stack on CuPy or a Dask cluster; read and write Measurement Sets, Zarr, and FITS.

Closures · Array backends · Pipelines · I/O

Notebooks without installing: Binder. How the pieces fit together: composability, flexibility, extensibility, adaptability.

Install

Python 3.11–3.13. The SKA extra index is required for a few dependencies.

pip install --extra-index-url https://artefact.skao.int/repository/pypi-internal/simple pyralysis[all]

GPU: micromamba create -f environment_cuda13.yml (Pascal: environment_cuda12.yml), then pip install -e .. Details: installation.

Minimal example

Simulate a point source, add thermal noise, make a natural-weighted dirty image:

from importlib.resources import files
from astropy import units as u
from pyralysis.io.antenna_config_io import AntennaConfigurationIo
from pyralysis.simulation import Simulator
from pyralysis.models.sky import PointSource
from pyralysis.injectors import ThermalNoiseInjector
from pyralysis.transformers.weighting_schemes import Natural
from pyralysis.transformers import DirtyMapper

cfg = files("pyralysis.simulation") / "antenna_configs" / "vla.c.cfg"
interferometer = AntennaConfigurationIo(input_name=str(cfg)).read()
interferometer.configure_observation(
    min_frequency=1e9 * u.Hz, max_frequency=1.1e9 * u.Hz, frequency_step=1e7 * u.Hz,
    right_ascension="12h00m00s", declination="45d00m00s",
    integration_time=10 * u.s, observation_time="1h",
)
source = PointSource(
    reference_intensity=1.0 * u.Jy, sky_position="12h00m00s 45d00m00s",
    reference_frequency=1e9 * u.Hz,
)
dataset = Simulator(interferometer=interferometer, sources=source).simulate(create_dataset=True)
dataset = ThermalNoiseInjector(system_temperature=50, integration_time=10, channel_bandwidth=1e6).apply(dataset)

imsize, cellsize = 128, dataset.theo_resolution / 3.5
Natural(imsize=imsize, cellsize=cellsize, input_data=dataset).transform()
dataset.calculate_psf()
dirty, _beam = DirtyMapper(input_data=dataset, imsize=imsize, cellsize=cellsize, stokes=["I"]).transform()

Reconstruction (χ² + L1, FISTA, GPU) is the same composition as the figures — optimization, quickstart.

Links

Docs · API · Examples · Contributing · Changelog · Issues

@software{carcamo2021pyralysis,
  author = {Miguel Cárcamo},
  title = {Pyralysis: A Python framework for radio interferometric imaging and simulation},
  year = {2021},
  url = {https://gitlab.com/clirai/pyralysis},
  note = {https://pyralysis.readthedocs.io/}
}

GPL-3.0-only — see LICENSE. Contact: miguel.carcamo@usach.cl