PUQ — Physical Units and Quantities

The PUQ (Physical Units and Quantities) module extends the numerical foundation with physical dimensions, units, and uncertainties. It provides representations of physical quantities and supports unit conversion, dimensional analysis, arithmetic, uncertainty propagation, and unit-aware expressions.

PUQ supports multiple unit systems, including SI, US customary, and electrostatic (ESU) systems, together with unit prefixes and conversions between compatible units. Physical quantities can therefore retain their units and associated uncertainty throughout calculations rather than treating them as external metadata.

PUQ is closely connected to PUEL (Physical Units Expression Language), which provides a formal language for describing physical quantities and unit expressions. The PUQ unit solver and calculator are built on the EXS expression-solving infrastructure, allowing unit expressions and calculations to be parsed and evaluated using the same general mechanism as other SciNumTools expression languages.

• Quantities and arithmetic — construct quantities, retain units and uncertainties, and use dimensional arithmetic.

• PUEL calculation — evaluate unit-aware expressions with the PUQ calculator.

• Conversion and unit systems — convert compatible quantities and work with unit-system context.