FunctionUnitBase¶
-
class
astropy.units.function.
FunctionUnitBase
(physical_unit=None, function_unit=None)[source]¶ Bases:
object
Abstract base class for function units.
Function units are functions containing a physical unit, such as dB(mW). Most of the arithmetic operations on function units are defined in this base class.
While instantiation is defined, this class should not be used directly. Rather, subclasses should be used that override the abstract properties
_default_function_unit
and_quantity_class
, and the abstract methodsfrom_physical
, andto_physical
.- Parameters
Attributes Summary
Copy the current function unit with the physical unit in CGS.
List of equivalencies between function and physical units.
Return the physical type of the physical unit (e.g., ‘length’).
Copy the current function unit with the physical unit in SI.
Methods Summary
decompose
(self[, bases])Copy the current unit with the physical unit decomposed.
from_physical
(self, x)Transformation from value in physical to value in function units.
is_equivalent
(self, other[, equivalencies])Returns
True
if this unit is equivalent toother
.is_unity
(self)to
(self, other[, value, equivalencies])Return the converted values in the specified unit.
to_physical
(self, x)Transformation from value in function to value in physical units.
to_string
(self[, format])Output the unit in the given format as a string.
Attributes Documentation
-
cgs
¶ Copy the current function unit with the physical unit in CGS.
-
equivalencies
¶ List of equivalencies between function and physical units.
Uses the
from_physical
andto_physical
methods.
-
function_unit
¶
-
physical_type
¶ Return the physical type of the physical unit (e.g., ‘length’).
-
physical_unit
¶
-
si
¶ Copy the current function unit with the physical unit in SI.
Methods Documentation
-
decompose
(self, bases=set())[source]¶ Copy the current unit with the physical unit decomposed.
For details, see
decompose
.
-
abstract
from_physical
(self, x)[source]¶ Transformation from value in physical to value in function units.
This method should be overridden by subclasses. It is used to provide automatic transformations using an equivalency.
-
is_equivalent
(self, other, equivalencies=[])[source]¶ Returns
True
if this unit is equivalent toother
.- Parameters
- otherunit object or string or tuple
The unit to convert to. If a tuple of units is specified, this method returns true if the unit matches any of those in the tuple.
- equivalencieslist of equivalence pairs, optional
A list of equivalence pairs to try if the units are not directly convertible. See Equivalencies. This list is in addition to the built-in equivalencies between the function unit and the physical one, as well as possible global defaults set by, e.g.,
set_enabled_equivalencies
. UseNone
to turn off any global equivalencies.
- Returns
- bool
-
to
(self, other, value=1.0, equivalencies=[])[source]¶ Return the converted values in the specified unit.
- Parameters
- other
Unit
object,FunctionUnitBase
object or string The unit to convert to.
- valuescalar int or float, or sequence convertible to array, optional
Value(s) in the current unit to be converted to the specified unit. If not provided, defaults to 1.0.
- equivalencieslist of equivalence pairs, optional
A list of equivalence pairs to try if the units are not directly convertible. See Equivalencies. This list is in meant to treat only equivalencies between different physical units; the build-in equivalency between the function unit and the physical one is automatically taken into account.
- other
- Returns
- valuesscalar or array
Converted value(s). Input value sequences are returned as numpy arrays.
- Raises
- UnitsError
If units are inconsistent.
-
abstract
to_physical
(self, x)[source]¶ Transformation from value in function to value in physical units.
This method should be overridden by subclasses. It is used to provide automatic transformations using an equivalency.
-
to_string
(self, format='generic')[source]¶ Output the unit in the given format as a string.
The physical unit is appended, within parentheses, to the function unit, as in “dB(mW)”, with both units set using the given format
- Parameters
- format
astropy.units.format.Base
instance or str The name of a format or a formatter object. If not provided, defaults to the generic format.
- format