natu

Natural units in Python

Warning: This project is currently in a pre-release state. It will be officially released once the unit tests are complete.

natu is a free, open-source package to represent physical quantities. There are many Python packages that deal with units and quantities, but natu is uniquely system-independent. The units are derived from physical constants with adjustable values and dimensions. The value of a unit is factored into a quantity so that the quantity is not "in" any particular unit. This has the following advantages:

• Flexible: Different unit systems, including natural units (hence the name "natu"), can be represented by simply adjusting the base physical constants.
• Simple: Unit conversion is inherent. This results in quick computations and a small code base (about 1500 lines). By default, dimensions and display units are tracked to catch errors and for string formatting. This can be disabled to nearly eliminate the computational overhead while still providing the core features.
• Intuitive: Each unit is a fixed quantity that is treated as a mathematical entity. A variable quantity is expressed as the product of a number and a unit, as stated by BIPM.
• Representative: The design reflects the way modern units are defined. Standards organizations such as NIST assign values to universal physical constants so that the values of units can be determined by physical experiments instead of prototypes.
• Scalable: The values of the base physical constants can scaled to prevent exponent overflow, regardless of the units used.

For example, you can do this:

>>> from natu.units import degC, K
>>> 0*degC + 100*K
100.0 degC

Please see the tutorial for more examples and visit the main website for the full documentation.

Installation

The easiest way is to install natu is to use pip:

> pip install natu

On Linux, it may be necessary to have root privileges:

$ sudo pip install natu

License terms and development

natu is published under a BSD-compatible license. Please share any improvements you make, preferably as a pull request to the master branch of the GitHub repository. There are useful development scripts in the hooks folder. If you find a bug, have a suggestion, or just want to leave a comment, please open an issue.