Chain

The Chain class object allows for easy interaction with a Commander chainfile.

class cosmoglobe.h5.chain.Chain(path, burn_in=None)[source]

An interface for Cosmoglobe chainfiles.

This class aims to provide a convenient interface for working with Cosmoglobe chain files.

__init__(path, burn_in=None)[source]

Validate and initialize the Chain object.

Parameters
  • path (str | Path) – Path to the chainfile.

  • burn_in (Optional[int]) – Burn in sample. All samples prior to (and including) the burn in sample is discarded.

combine(other_chain, group_list, new_name=None)[source]

Creates a new chainfile that combines specific groups from two chains.

Return type

None

property components: list[str]

List of the sky components in the chain.

copy(samples=- 1, new_name=None)[source]

Creates a copy of the chain with a single or multiple samples.

Return type

None

get(key, *, samples=None, unpack=True)[source]

Returns the value of an key for all samples.

Parameters
  • key (str) – The path to an item that has been sampled in the chain, e.g ‘dust/amp_alm’.

  • samples (Optional[range | int | Sequence[int]]) – An int or a range of samples for which to return the value. If None, all samples in the chain are used.

  • unpack (bool) – If True, alms are unpacked from Commander format to healpy format. Default is True

Returns

The value of the key for each samples.

Return type

values

load(key, *, samples=None)[source]

Returns a generator to be used in a for loop.

NOTE to devs: The unpack_alms decorator wont work on this function due to it not processing the returned data until it is iterated over.

Parameters
  • key (str) – The path to an item that has been sampled in the chain, e.g ‘dust/amp_alm’.

  • samples (Optional[range | int | Sequence[int]]) – An int or a range of samples to average over. If None, all samples in the chain are used.

Return type

A generator that can be looped over to yield each sampled value.

mean(key, *, samples=None, unpack=True)[source]

Returns the mean of an key over all samples.

Parameters
  • key (str) – The path to an item that has been sampled in the chain, e.g ‘dust/amp_alm’.

  • samples (Optional[range | int | Sequence[int]]) – An int or a range of samples to average over. If None, all samples in the chain are used.

  • unpack (bool) – If True, alms are unpacked from Commander format to healpy format. Default is True

Returns

The averaged value of the key over all samples.

Return type

value

property nsamples: int

Number of samples in the chain.

Return type

int

property parameters: dict[str, dict[str, Any]]

Dictionary of the parameters in the parameter group in the chain.

property path: pathlib.Path

Path to the chainfile.

Return type

Path

property samples: list[str]

List of all samples in the chain.

stddev(key, *, alm2map=False, samples=None)[source]

Returns the stddev of an key over all samples.

Parameters
  • key (str) – The path to an item that has been sampled in the chain, e.g ‘dust/amp_alm’.

  • samples (Optional[range | int | Sequence[int]]) – An int or a range of samples to average over. If None, all samples in the chain are used.

Returns

The averaged value of the key over all samples.

Return type

value

property tree

Prints group and dataset structure of the chainfile.

property version: cosmoglobe.h5.ChainVersion

Chain version.

Return type

ChainVersion