CompositeUnit¶

class astropy.units.CompositeUnit(scale, bases, powers, decompose=False, decompose_bases={}, _error_check=True)[source]¶

Create a composite unit using expressions of previously defined units.

Direct use of this class is not recommended. Instead use the factory function Unit and arithmetic operators to compose units.

Parameters:	scale : number A scaling factor for the unit. bases : sequence of `UnitBase` A sequence of units this unit is composed of. powers : sequence of numbers A sequence of powers (in parallel with `bases`) for each of the base units.

Attributes Summary

`bases`	Return the bases of the composite unit.
`powers`	Return the powers of the composite unit.
`scale`	Return the scale of the composite unit.

Methods Summary

`decompose`(self[, bases])	Return a unit object composed of only irreducible units.
`is_unity`(self)	Returns `True` if the unit is unscaled and dimensionless.

Attributes Documentation

Methods Documentation

decompose(self, bases=set())[source]¶

Return a unit object composed of only irreducible units.

Parameters:	bases : sequence of UnitBase, optional The bases to decompose into. When not provided, decomposes down to any irreducible units. When provided, the decomposed result will only contain the given units. This will raises a `UnitsError` if it’s not possible to do so.
Returns:	unit : CompositeUnit object New object containing only irreducible unit objects.

is_unity(self)[source]¶: Returns True if the unit is unscaled and dimensionless.