Backend agnostic astropy-like cosmology
An efficient implementation of astropy-like cosmology compatible
with numpy-like backends, e.g., jax and cupy.
There are two main features leading to superior efficiency to astropy:
Integrals of \(E(z)\) and related functions are performed analytically with Pade approximations or analytic expressions using hypergeometric functions.
Support for
jaxandcupybackends allow hardware acceleration, just-in-time compilation, and automatic differentiation.
The primary limitations are:
Only flat cosmologies are supported with two components with constant equations of state, e.g.,
FlatwCDM.Approximations to the various integrals generally agree with
astropyat the <0.1% level.The
astropyunits are incompatible with thecupybackend. Units are supported with thejaxbackend usingunxt.
Installation and contribution
wcosmo can be installed via conda-forge, pypi or from
source.
$ mamba install -c conda-forge wcosmo
$ pip install wcosmo
$ pip install git+https://github.com/ColmTalbot/wcosmo.git
for development you should follow a standard fork-and-pull workflow.
First create a new fork at
github.com/UserName/wcosmo.Clone your fork
$ git clone git@github.com:UserName/wcosmo.gitor use a GitHub codespace.
Install the local version with
$ python -m pip install .Make any desired edits and push to your fork.
Open a pull request into
git@github.com:ColmTalbot/wcosmo.git.
Basic usage
To import an astropy-like cosmology
>>> from wcosmo import FlatwCDM
>>> cosmology = FlatwCDM(H0=70, Om0=0.3, w0=-1)
>>> cosmology.luminosity_distance(1)
The built-in cosmologies in astropy are all available, e.g.,
>>> from wcosmo import Planck18
>>> Planck18.luminosity_distance(1)
<Quantity 6797.43628659 Mpc>
they can also be accessed using wcosmo.available
>>> from wcosmo import available
>>> available["Planck18"].luminosity_distance(1)
<Quantity 6797.43628659 Mpc>
Explicit usage of astropy units can be freely enabled/disabled.
In this case, the values will have the default units for each method.
>>> from wcosmo import FlatwCDM
>>> from wcosmo.utils import disable_units, enable_units
>>> cosmology = FlatwCDM(H0=70, Om0=0.3, w0=-1)
>>> disable_units()
>>> cosmology.luminosity_distance(1)
6607.657732077576
>>> enable_units()
>>> cosmology.luminosity_distance(1)
<Quantity 6607.65773208 Mpc>
Changing backend
wcosmo mostly relies on implicit backend switching. The backend is
determined automatically based on the input arguments. When an input value is
a Python built-in type, the default backend is chosen using the
environment variable WCOSMO_ARRAY_API. The default is numpy.
GWPopulation
The original intention for this package was for use with GWPopulation.
This code is automatically used in GWPopulation when using either
gwpopulation.experimental.cosmo_models.CosmoModel and/or
PowerLawRedshift
Metadata
Release files for wcosmo 0.5.4
For a detailed explanation of source distributions (sdists) and built distributions (wheels), please see the package formats documentation.
Source distribution (sdist)
| File | Size | Uploaded | |
|---|---|---|---|
| wcosmo-0.5.4.tar.gz | 6.8 MB | Details |
Built distribution (wheel)
| File | Interpreter | ABI | Platform | Reset |
|---|---|---|---|---|
| wcosmo-0.5.4-py3-none-any.whl | Python 3 | none | any | Details |
Total release size: 6.8 MB
Release files / wcosmo-0.5.4.tar.gz
| Download URL | wcosmo-0.5.4.tar.gz |
|---|---|
| Size | 6.8 MB |
| Tags | Source |
|
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| Tags | Python 3 |
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| Uploaded via |
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