Units registry

fpc.units

units.py - one shared Pint unit registry for the whole project.

Pint attaches physical units to numbers, so 5 * meter knows it is a length, converts itself (.to("mm")), and refuses to add a length to a time. This catches the unit-mismatch mistakes that plain floats silently let through.

IMPORTANT: Pint quantities can only be combined if they come from the SAME registry. So the project defines exactly one here and everything imports it::

from fpc.units import ureg, Q_

length = 2 * ureg.meter          # or:  Q_(2, "meter")
force = Q_(1000, "newton")
print((force / length).to("N/mm"))