Dimensions

How unxt.dimension_of interacts with parametric quantities. For dimensions in general, see the unxt Dimensions guide.

>>> import unxt as u
>>> import unxts.parametric as up

The dimension of a parametric class

Because a ParametricQuantity encodes its dimension in the class itself, unxt.dimension_of works on a parametrized class — not only on instances:

>>> u.dimension_of(up.PQ["length"])  # a parameterized class carries a dimension
PhysicalType('length')

>>> try: u.dimension_of(up.PQ)  # ... the unparameterized class does not
... except Exception as e: print(e)
can only get dimensions from parametrized ParametricQuantity -- ParametricQuantity[dim].

The default Quantity carries no dimension, so dimension_of on the class raises (only instances have a unit, and hence a dimension) — see the unxt Dimensions guide.