"""Convenience objects and functions for unit manipulation."""
import enum
from .misc import find
[docs]@enum.unique
class SI(enum.Enum):
"""Enum defining common SI unit constant names. Look-up
the corresponding values with the `finesse.utilities.SI_MAP`
dictionary.
Examples
--------
To get the constant for `SI.MILLI` simply look-up:
>>> SI_MAP[SI.MILLI]
1e-3
"""
YOCTO = 0
ZEPTO = 1
ATTO = 2
FEMTO = 3
PICO = 4
NANO = 5
MICRO = 6
MILLI = 7
CENTI = 8
DECI = 9
NONE = 10
KILO = 11
MEGA = 12
GIGA = 13
TERA = 14
PETA = 15
SI_VALUE = {
SI.YOCTO: 1e-24,
SI.ZEPTO: 1e-21,
SI.ATTO: 1e-18,
SI.FEMTO: 1e-15,
SI.PICO: 1e-12,
SI.NANO: 1e-9,
SI.MICRO: 1e-6,
SI.MILLI: 1e-3,
SI.CENTI: 1e-2,
SI.DECI: 1e-1,
SI.NONE: 1.0,
SI.KILO: 1e3,
SI.MEGA: 1e6,
SI.GIGA: 1e9,
SI.TERA: 1e12,
SI.PETA: 1e15,
}
SI_LABEL = {
SI.YOCTO: "y",
SI.ZEPTO: "z",
SI.ATTO: "a",
SI.FEMTO: "f",
SI.PICO: "p",
SI.NANO: "n",
SI.MICRO: "u",
SI.MILLI: "m",
SI.CENTI: "c",
SI.DECI: "d",
SI.KILO: "k",
SI.MEGA: "M",
SI.GIGA: "G",
SI.TERA: "T",
SI.PETA: "P",
}
[docs]def get_SI_value(name):
"""Get an SI value by name.
Valid names correspond to the ``values()`` of the ``finesse.utilities.SI_LABEL``
dict.
Parameters
----------
name : str
Label name of the SI value (e.g. "m" for milli, "G" for giga).
Returns
-------
value : float
Value corresponding to the SI name.
"""
keys = list(SI_LABEL.keys())
values = list(SI_LABEL.values())
idx = find(values, name)
if idx is None:
raise ValueError(f"Invalid SI name {name}.")
key = keys[idx]
return SI_VALUE[key]