opensemantic.characteristics.quantitative

Library with Python models derived from the page package world.opensemantic.characteristics.quantitative

Quantities and units generated from QUDT. pint mapping was done with support from ucumvert

Usage

from opensemantic.characteristics.quantitative import (
    Length, LengthUnit, Width, Area, AreaUnit, QuantityValue,
)

# Create typed quantity values
length = Length(value=1.0, unit=LengthUnit.meter)
width = Width(value=200, unit=LengthUnit.milli_meter)

# Arithmetic — units are tracked automatically via pint
area = length * width
print(area.value, area.unit.name)  # 200000.0 milli_meter_squared
assert isinstance(area, Area)

# Unit conversion
area_cm2 = area.to_unit(AreaUnit.centi_meter_squared)
print(area_cm2.value)  # 2000.0
assert area == area_cm2  # physical equality across units

# Addition with automatic unit conversion
l1 = Length(value=1.0, unit=LengthUnit.milli_meter)
l2 = Length(value=1.0, unit=LengthUnit.meter)
print((l1 + l2).value)  # 1.001 (in meters)

# pint interop: round-trip to/from pint.Quantity
q_pint = l1.to_pint()                    # -> 1.0 millimeter
restored = QuantityValue.from_pint(q_pint)  # -> Length(1.0, milli_meter)
assert l1 == restored

# JSON serialization (via oold's unified API)
print(l1.to_json())
# {'type': ['Category:OSWee9c7e5c...'], 'value': 1.0, 'unit': 'Item:OSWf101d25e...'}

Round-tripping derived units

from_pint recovers a typed QuantityValue even when the exact unit symbol is not in the registry - e.g. derived units (watt, joule, ohm) or composed results such as volt * ampere. When the symbol is unknown it falls back to the quantity's dimensionality, mapping it to a representative SI-coherent unit via DIMENSION_TO_UNIT (generated into _dimensions.py by scripts/post_process.py):

from opensemantic.characteristics.quantitative import (
    Voltage, VoltageUnit, ElectricCurrent, ElectricCurrentUnit, Power,
)

power = Voltage(value=3.7, unit=VoltageUnit.volt) * ElectricCurrent(
    value=2.0, unit=ElectricCurrentUnit.ampere
)
assert isinstance(power, Power)  # volt * ampere -> watt

Compact export

exclude_defaults=True omits values left at their default (e.g. the default unit) for a minimal, portable representation:

length = Length(value=1.0, unit=LengthUnit.meter)
print(length.to_json(exclude_defaults=True))  # {'value': 1.0}

See examples/ for more, including tabular data with pandas and a tensile test analysis.

TODO: Unit Name Conflicts in _collection.py

18 unit member names appear in multiple *Unit enum classes with different OSW IDs. The first occurrence goes into _collection.py; conflicting entries remain hardcoded in _model.py. These likely stem from upstream QUDT modeling where the same unit name maps to different physical quantities.

Status

Note

This project has been set up using PyScaffold 4.6. For details and usage information on PyScaffold see https://pyscaffold.org/.