unit-propagation 0.2

physical quantities (numbers with units)

Author: Ken Kundert

Version: 0.2

Released: 2026-06-27

This is a package used to experiment with adding unit propagation to QuantiPhy. It currently employs simple-minded simplification rules that handle many common cases but not all. Also, there is a strong emphasis on simple electrical unit scenarios. Even so, it shows promise for use in well controlled settings.

Here is simple example:

>>> from unit_propagation import UnitPropagatingQuantity as Quantity, QuantiPhyError

>>> try:
...     v = Quantity("2.5V")
...     i = Quantity("100nA")
...     print(v/i)
... except QuantiPhyError as e:
...     print(f"error: {e!s}")
25 MΩ

Operations can also involve integers, floats and strings:

>>> Kvco = Quantity(500e6, "Hz") / "500mV"
>>> print(Kvco)
1 GHz/V

>>> Vdd = Quantity("2.5V")
>>> halfVdd = Vdd / 2
>>> print(halfVdd)
1.25 V

Included in the package is a simple RPN calculator that allows you to explore the capabilities and limitations of unit propagation.