Dimension¶
Dimension is a family of monovalue types representing equivalence classes
of units. Each class defines a collection of units which can be meaningfully added, subtracted, and
compared with each other. Familiar examples of Dimension include length, time, temperature,
speed, and so on.
Dimensions form a vector space. We choose
certain “base dimensions” as the basis vectors for this space. As with other vector spaces in our
library, Dimension values can be multiplied, divided, and raised to (rational) powers, and this
arithmetic always takes place at compile time.
Dimension is an implementation detail. Most end users will never name dimensions in their code,
and never see them in their compiler errors. Instead, users will work with units,
which each carry their own dimension information. The main situation where an end user would use
Dimension directly is to define the first unit for a novel base dimension.
Included base dimensions¶
Au includes the following base dimensions:
LengthMassTimeCurrentTemperatureAngleInformationAmountOfSubstanceLuminousIntensity
These comprise each of the seven base dimensions in the SI, with the addition of Angle and
Information.