pyralysis 1.0.0

PYthon Radio Astronomy anaLYSis and Image Synthesis

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Pyralysis

Pyralysis is an open-source Python library for radio astronomy imaging, simulation, and optimization. It is designed to be easy to install, learn, and use for modern radio interferometry workflows.

For full documentation, tutorials, and API reference, see the Pyralysis documentation on ReadTheDocs:

• Pyralysis documentation

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Install in three steps

• 1. Create a Python environment (Python 3.9–3.12 recommended). Use whatever you prefer: conda, mamba, micromamba, or plain venv.

• 2. Install from PyPI using the SKA extra index.

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

This installs Pyralysis plus the common optional dependencies (FFT and GPU‑related extras, where available). If you need a development install, specific environments, or Docker images, see:

• Installation guide

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Minimal example

Start by simulating a small dataset and then add thermal noise:

from pyralysis.io.antenna_config_io import AntennaConfigurationIo
from pyralysis.simulation import Simulator
from pyralysis.models.sky import PointSource
from pyralysis.injectors import ThermalNoiseInjector

# Load array configuration
interferometer = AntennaConfigurationIo(input_name="path/to/array.cfg").read()
interferometer.configure_observation(
    min_frequency_hz=1e9, max_frequency_hz=1.1e9, frequency_step_hz=1e7,
    right_ascension="12:00:00", declination="45:00:00",
    integration_time=10, observation_time="1h"
)

# Define a source and simulate
source = PointSource(
    reference_intensity=1.0,
    sky_position="12:00:00 45:00:00",
    reference_frequency=1e9,
)
sim = Simulator(interferometer=interferometer, sources=source)
dataset = sim.simulate(create_dataset=True)

# Add thermal noise
thermal = ThermalNoiseInjector(system_temperature=50, integration_time=10, channel_bandwidth=1e6)
noisy_dataset = thermal.apply(dataset)

For more simulation examples (arrays, sky models, injectors, and data access), see:

• Simulation guide

Reconstruction example

Next, reconstruct an image from the (noisy) visibilities using an objective function and L‑BFGS:

from pyralysis.reconstruction import Image
from pyralysis.optimization import ObjectiveFunction
from pyralysis.optimization.terms import ChiSquared, L1Norm
from pyralysis.optimization.optimizer import LBFGS
from pyralysis.measurement import ModelVisibility

# Create initial image (e.g. empty sky model)
image = Image.empty(imsize=(512, 512), cellsize=0.001)  # adjust to your case

# Build model visibility from dataset and image
model_visibility = ModelVisibility(dataset=noisy_dataset, image=image)

# Define objective function: data fidelity + simple L1 regularization
terms = [
    ChiSquared(model_visibility=model_visibility, penalization_factor=1.0),
    L1Norm(penalization_factor=0.01),
]
objective = ObjectiveFunction(term_list=terms, image=image, persist_gradient=True)

# Run L-BFGS reconstruction
optimizer = LBFGS(objective_function=objective, parameter=image)
reconstructed_image = optimizer.optimize()

For detailed reconstruction workflows (measurement operator, regularizers, optimizers), see:

• Optimization
• Measurement operator

Examples in this repository

• Jupyter notebooks are in examples/notebooks/.
• CLI scripts are in examples/scripts/, split by style:
  • *_components.py for explicit class composition.
  • *_pipeline.py for pipeline-based orchestration.
• Current paired scripts:
  • dirtymapper_components.py / dirtymapper_pipeline.py
  • optimization_components.py / optimization_pipeline.py
  • simulation_components.py / simulation_pipeline.py

See the documentation page for quick usage patterns:

• Repository examples

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Learn more

• User guide and tutorials: https://pyralysis.readthedocs.io/en/latest/
• API reference: https://pyralysis.readthedocs.io/en/latest/api/index.html
• Data model and measurement operator: https://pyralysis.readthedocs.io/en/latest/data_model.html

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Contributing and development

• Contributing guide: see CONTRIBUTING.md
• Running tests and development setup: https://pyralysis.readthedocs.io/en/latest/development.html
• Issue tracker: https://gitlab.com/clirai/pyralysis/-/issues

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Citation and license

If you use Pyralysis in your research, please consider citing:

@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}
}

Pyralysis is distributed under the terms of the GNU General Public License version 3 (GPLv3). See LICENSE for details.

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Contact

• Documentation: https://pyralysis.readthedocs.io
• Issues: https://gitlab.com/clirai/pyralysis/-/issues
• Lead developer: [e-mail]