sampler-template

Template for sampler plugins in bilby

There are three main components to a sampler plugin for bilby:

• The sampler class
• The pyproject.toml
• The test suite

The sampler class

This is the interface between the external sampling code and bilby, in this template repo is it located in src/demo_sampler_bilby/plugin.py.

The class should inherit from one of:

• bilby.core.sampler.Sampler
• bilby.core.sampler.MCMCSampler
• bilby.core.sampler.NestedSampler

The sampler is run in the run_sampler method

pyproject.toml

Various fields in the pyproject.toml need to be set, these are:

• name: this is the name Python package, we recommend using <name of your sampler>_bilby
• author: this should include any authors
• dependencies: any dependencies should be included here, this must include bilby
• [project.entry-points."bilby.samplers"] see below

Adding the entry points

This section of the pyproject.toml makes the sampler 'visible' within bilby.

[project.entry-points."bilby.samplers"]
demo_sampler = "demo_sampler_bilby.plugin:DemoSampler"

The name of the sampler within bilby is determined based on the name used here (e.g. demo_sampler in this case).

The string should points to the file and, after the colon, the sampler class.

Tests

The plugin should include a test suite.

tests/test_bilby_integration.py includes a standard test that all samplers should pass but other tests can be included in here. The file should be updated name matches the name of the sampler provided by the plugin and any keyword arguments should be set.

Continuous Integration

The tests are run automatically via GitHub Actions. These are configured in .github/workflow/test.yaml. You may wish to change the version of Python being tested or included additional configuration, e.g. for more complex installation processes.

Plugin in an existing package

It is also possible to include the plugin in an existing package rather than creating a separate plugin package. In this case, you need to define the sampler class somewhere within the existing package and then add an entry point.