https://github.com/quatrope/uttrs
uttrs provides utilities for creating attrs based classes with astropy units.
https://github.com/quatrope/uttrs
astronomy astropy astropy-units attrs classes oop units-measures-converter
Last synced: 6 months ago
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uttrs provides utilities for creating attrs based classes with astropy units.
- Host: GitHub
- URL: https://github.com/quatrope/uttrs
- Owner: quatrope
- License: bsd-3-clause
- Created: 2020-11-15T13:47:15.000Z (almost 5 years ago)
- Default Branch: main
- Last Pushed: 2021-07-14T04:16:13.000Z (over 4 years ago)
- Last Synced: 2025-03-27T21:38:37.680Z (7 months ago)
- Topics: astronomy, astropy, astropy-units, attrs, classes, oop, units-measures-converter
- Language: Python
- Homepage:
- Size: 104 KB
- Stars: 4
- Watchers: 4
- Forks: 1
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
- License: LICENSE
- Code of conduct: CODE_OF_CONDUCT.md
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README
# Uttrs
`uttrs` seeks to interoperate Classes definided using attrs and *astropy units* in a simple manner.
----
[](https://quatrope.github.io/)
[](https://travis-ci.com/quatrope/uttrs)
[](https://uttrs.readthedocs.io/en/latest/?badge=latest)
[](https://www.tldrlegal.com/l/bsd3)
[](https://badge.fury.io/py/uttrs)
[](https://pypi.org/project/uttrs/)
**uttrs** is mainly three functions:
- `uttr.ib` which generates attributes sensitive to units.
- `uttr.array_accessor` which allows access to attributes linked to units, and transform them into numpy arrays.
- `uttr.s` a class decorator to automatically add the `array_accessor`.
## Code and issues
The entire source code of is hosted in GitHub
[https://github.com/quatrope/uttrs/](https://github.com/quatrope/uttrs/)
## License
Uttrs is under
[The BSD-3 License](https://github.com/quatrope/uttrs/blob/master/LICENSE)
The BSD 3-clause license allows you almost unlimited freedom with the software so long as you include the BSD copyright and license notice in it (found in Fulltext).
## Installation
This is the recommended way to install uttrs.
### Installing with pip
Make sure that the Python interpreter can load uttrs code.
The most convenient way to do this is to use virtualenv, virtualenvwrapper, and pip.
After setting up and activating the virtualenv, run the following command:
```console
$ pip install uttrs
...
```
That should be it all.
### Installing the development version
If you’d like to be able to update your uttrs code occasionally with the latest bug fixes and improvements, follow these instructions:
Make sure that you have Git installed and that you can run its commands from a shell.
(Enter *git help* at a shell prompt to test this.)
Check out uttrs main development branch like so:
```console
$ git clone https://github.com/quatrope/uttrs
...
```
This will create a directory *uttrs* in your current directory.
Then you can proceed to install with the commands
```console
$ cd uttrs
$ pip install -e .
...
```
## Documentation
The full documentation of the project are available in
[https://uttrs.readthedocs.io/](https://uttrs.readthedocs.io/)
## Contact
For bugs or question please contact
> **Juan B. Cabral:** [jbcabral@unc.edu.ar](jbcabral@unc.edu.ar)
## Quick Start
The following piece of code is an example prototype of a Class representing a Galaxy.
The Galaxy contains:
- three arrays (`x`, `y`, `z`) with particle positions, measured in *kiloparsecs* (`u.kpc`).
- three arrays (`vx`, `vy`, `vz`) for the particle velocities, measured in *Km/s* (`u.kms/u.s`).
- an array (`m`) of particle masses, expressed in *solar masses* (`u.M_sun`).
- a free text for note taking in `notes`.
In every case we would like to access to position, velocity and mass of the particles, with and without units (as `np.ndarray`).
Suggested units in the information of the attributes behave like this:
- If the user makes the class instance without unit specification then default assumed unit is used.
- If, otherwise, another unit is used as input, it is validated the feasibility of the conversion to default unit.
```python
import uttr
import astropy.units as u
@uttr.s
class Galaxy:
x = uttr.ib(unit=u.kpc)
y = uttr.ib(unit=u.kpc)
z = uttr.ib(unit=u.kpc)
vx = uttr.ib(unit=u.km/u.s)
vy = uttr.ib(unit=u.km/u.s)
vz = uttr.ib(unit=u.km/u.s)
m = uttr.ib(unit=u.M_sun)
notes = uttr.ib(converter=str)
```
## Creating a galaxy
```python
>>> import numpy as np
>>> import astropy.units as u
# Creating the particle arrays
>>> x = np.random.randint(1000, 10_000, size=5) + np.random.rand(5)
>>> y = np.random.randint(1000, 10_000, size=5) + np.random.rand(5)
>>> z = np.random.randint(1000, 10_000, size=5) + np.random.rand(5)
>>> vx = np.random.randint(1000, 10_000, size=5) + np.random.rand(5)
>>> vy = np.random.randint(1000, 10_000, size=5) + np.random.rand(5)
>>> vz = np.random.randint(1000, 10_000, size=5) + np.random.rand(5)
>>> m = np.random.randint(1000, 10_000, size=5) + np.random.rand(5)
>>> gal = Galaxy(
... x = x * u.kpc, # kpc is the suggested unit
... y = y * u.mpc, # milliparsec is equivalent to kpc
... z = z, # we assume is the suggested kpc unit
... vx = vx * (u.km/u.s), # the suggested unit
... vy = vy * (u.km/u.s), # the suggested unit
... vz = vz, # the suggested unit
... m = m * u.M_sun, # the suggested unit
... notes="a random galaxy made with random numbers")
>>> gal
Galaxy(
x=,
y=,
z=,
vx=,
vy=,
vz=,
m=,
notes='a random galaxy made with random numbers')
# we can access al the attributes in the traditional python way
>>> gal.x
>>> gal.vz # z is now a km/s
# We stored y as mpc (milliparsec)
>>> gal.y
```
## Simple interaction with `numpy.ndarray`
We can access all the same attributes declared with `uttr.ib but` coerced to the default unit as numpy array.
```python
>>> gal.arr_.y
array([0.00809345, 0.00219855, 0.00546479, 0.00186072, 0.00363664])
```
The above code is equivalent to
```python
>>> gal.y.to_value(u.kpc)
array([0.00809345, 0.00219855, 0.00546479, 0.00186072, 0.00363664])
```
## Equivalent units errors
If we change the unit to something not equivalent to the default unit
declares in `uttr.ib` an exception is raised.
Lets fot example define `x` as a kilogram (`u.kg`)
```python
>>> gal = Galaxy(
... x = x * u.kg, # kg is not equivalent to kpc
... y = y,
... z = z,
... vx = vx,
... vy = vy,
... vz = vz,
... m = m,
... notes="a random galaxy made with random numbers")
ValueError: Unit of attribute 'x' must be equivalent to 'kpc'.Found 'kg'.
```
## References
### Astropy
> Price-Whelan, Adrian M., et al. "The Astropy project:
Building an open-science project and status of the v2. 0 core
package." The Astronomical Journal 156.3 (2018): 123.