unitflow 0.2.1

Elegant engineering math substrate for executable MBSE.

UnitFlow

Elegant engineering math for Python.

Unit algebra. Dimensional reasoning. Symbolic constraints. Array workflows. Built for engineers who refuse to compromise on correctness or beauty.

Installation

pip install unitflow

For NumPy support:

pip install unitflow[numpy]

The core library has zero dependencies. NumPy is optional.

Quick Start

from unitflow import m, cm, kg, s, N, kW, MW, rpm, rad, si

# Intuitive arithmetic
force = 2 * kg * 9.81 * (m / s**2)
print(force.to(N))              # 19.62 N

# Exact conversions across orders of magnitude
power = 5000 * si.W
print(power.to(kW))             # 5 kW
print(power.to(MW))             # 0.005 MW

# Angular speed with exact pi-bearing scale factors
angular = (3000 * rpm).to(rad / s)
print(angular)                  # 314.159... rad/s

# Semantic equality: same physics, same object
assert 1 * m == 100 * cm
assert hash(1 * m) == hash(100 * cm)

Features

• Clean Unit Algebra -- Immutable, composable units with automatic dimension tracking.
• Exact Scale Representation -- Rational arithmetic with explicit pi support. No floating-point drift.
• SI Prefix System -- Every standard prefix from pico to tera, generated programmatically.
• Torque vs Energy Disambiguation -- Same dimension, different meaning. UnitFlow knows the difference.
• Symbolic Constraints -- Define equations and inequalities as first-class Python objects for MBSE.
• NumPy Integration -- Array-backed quantities via __array_ufunc__ and __array_function__.
• JSON-Safe Serialization -- Quantities and constraint trees serialize to plain dicts.
• Explicit Errors -- Dimension mismatches and incompatible conversions fail loudly. No silent corruption.

Symbolic Constraints

from unitflow import symbol, N, kg, m, s, W, rpm, rad

F = symbol("F", unit=N)
mass = symbol("m", unit=kg)
a = symbol("a", unit=m / s**2)

newtons_law = F == mass * a          # Returns an Equation, not a bool

x = symbol("x", unit=m)
bounds = (0 * m <= x) & (x <= 10 * m)  # Conjunction of constraints

User-Defined Units

from unitflow import define_unit, UnitNamespace, Quantity, m, s, generate_prefixes
from fractions import Fraction

ft = define_unit(name="foot", symbol="ft", expr=Quantity(Fraction(3048, 10000), m))
print((6 * ft).to(m))  # 1.8288 m

aero = UnitNamespace("aero")
knot = aero.define_unit(name="knot", symbol="kn", expr=Quantity(Fraction(1852, 3600), m / s))
generate_prefixes(aero, knot, include={"milli", "kilo"})

Part of ThunderGraph

UnitFlow is the foundational math layer for ThunderGraph, an AI-powered model-based systems engineering platform.

Links

• GitHub Repository
• Full Documentation & Examples
• Contributing Guide

License

Apache 2.0