baseUnits

Float-based unit conversion factors for consistent unit systems.

Architecture

Every unit is a plain float equal to its conversion factor into a chosen consistent base system. Absolute SI values live in a single source of truth (_factors.py); a system factory derives a consistent set of float constants for any (length, force, time) triple. An opt-in baseUnits.checked submodule keeps a Quantity/Unit/Dimension runtime layer for safety-critical code.

Default system: N-mm-tonne-s

Quantity	Unit	Value
Length	mm	1.0
Force	N	1.0
Mass	tonne	1.0
Time	s	1.0
Pressure	MPa	1.0
g	gravity	9806.65

Available systems

All modules follow the <force>_<length>_<time> naming pattern.

• baseUnits.systems.N_mm_s — N-mm-tonne-s (default)
• baseUnits.systems.N_m_s — N-m-kg-s
• baseUnits.systems.kN_m_s — kN-m-tonne-s
• baseUnits.systems.kip_in_s — kip-inches-s
• baseUnits.systems.kgf_m_s — gravitational metric (mass derived = hyl)
• baseUnits.systems.tf_m_s — tonne-force metric (mass derived = 1000 hyl)
• baseUnits.systems.dyne_cm_s — CGS

Quickstart

from baseUnits import m, kN, MPa, g

length = 5 * m          # 5000.0 (mm)
load   = 100 * kN       # 100000.0 (N)
stress = 30 * MPa       # 30.0 (MPa)
weight = 80 * g         # 80 * 9806.65 (mm/s^2 acceleration scale)

Switching systems

from baseUnits.systems.kip_in_s import m, kN, ksi, BASE

print(BASE)             # "kip-inches-s"
print(5 * m)            # 196.85 (inches)

Opt-in dimensional safety

For runtime checks that catch dimension mismatches, use baseUnits.checked:

from baseUnits.checked import Quantity, m, mm, K, C

q = 5 * m
print(q.to(mm).value)   # 5000.0
print((1 * K).to(C).value)  # 1.0

Arithmetic on Quantity objects raises if you mix incompatible dimensions.

Installation

git clone https://github.com/nmorabowen/baseUnits.git
cd baseUnits
pip install -e .