parallax¶

utilipy.astro.parallax(arg, *, unit: Optional[astropy.units.Unit] = None, to_value: bool = False, equivalencies: Sequence = [], decompose: Union[bool, Sequence] = False, assumed_units: dict = {}, _skip_decorator: bool = False, **kw) → Any[source]¶

Parallax.

Other Parameters

unitastropy Unit or Quantity or str

sets the unit for the function evaluation. (default None) must be astropy-compatible unit specification. equivalent to func(*args, **kw).to(unit) if None, skips unit conversion. function arguments override decorator and function annotation arguments

to_valuebool

whether to return .to_value(unit) (default False) see astropy.units.Quantity.to_value function arguments override decorator and function annotation arguments

equivalencieslist

equivalencies for any units provided (default []) used by .to() and .to_value() function arguments override decorator and function annotation arguments

decomposebool or list

Decompose the unit into base units, can provide base as list. (default []) function arguments override decorator and function annotation arguments if bool, then do/don’t decompose if list, bases for .decompose(bases=[]) will first decompose, then apply unit, to_value, equivalencies

Decomposing then converting wastes time, since to(unit, equivalencies) internally does conversions. The only use for combining decompose with other params is with:

unit=None, to_value=True, equivalencies=[], decompose=[bases]

since this will decompose to desired bases then return the value

Note

for things which are not (u.Unit, u.core.IrreducibleUnit), tries wrapping in Unit() this allows things such as:

>>> x = 10 * u.km * u.s
>>> bases = [u.Unit(2 * u.km), u.s]
>>> x.decompose(bases=bases) 
<Quantity 5. 2 km s>

(this would normally return an error)

assumed_units: dict

dictionary of default units (default {})

>>> from utilipy.units.decorators import QuantityInputOutput
>>> dfu = {'x': u.km}
>>> x = 10
>>> y = 20*u.km
>>> @QuantityInputOutput.as_decorator(assumed_units=dfu)
... def add(x, y):
...     return x + y
>>> add(x, y) 
<Quantity 30.0 km>

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parallax¶