# -*- coding: utf-8 -*-
# Licensed under a 3-clause BSD style license - see LICENSE.rst
"""
This package defines colloquially used Imperial units. By default, they
are not enabled. To enable them, do::
>>> from astropy.units import imperial
>>> imperial.enable() # doctest: +SKIP
"""
from __future__ import (absolute_import, division, print_function,
unicode_literals)
from .core import UnitBase, def_unit
from . import si
_ns = globals()
###########################################################################
# LENGTH
def_unit(['inch'], 2.54 * si.cm, namespace=_ns,
doc="International inch")
def_unit(['ft', 'foot'], 12 * inch, namespace=_ns,
doc="International foot")
def_unit(['yd', 'yard'], 3 * ft, namespace=_ns,
doc="International yard")
def_unit(['mi', 'mile'], 5280 * ft, namespace=_ns,
doc="International mile")
def_unit(['nmi', 'nauticalmile', 'NM'], 1852 * si.m, namespace=_ns,
doc="Nautical mile")
###########################################################################
# AREAS
def_unit(['ac', 'acre'], 43560 * ft ** 2, namespace=_ns,
doc="International acre")
###########################################################################
# VOLUMES
def_unit(['gallon'], si.liter / 0.264172052, namespace=_ns,
doc="U.S. liquid gallon")
def_unit(['quart'], gallon / 4, namespace=_ns,
doc="U.S. liquid quart")
def_unit(['pint'], quart / 2, namespace=_ns,
doc="U.S. liquid pint")
def_unit(['cup'], pint / 2, namespace=_ns,
doc="U.S. customary cup")
def_unit(['foz', 'fluid_oz', 'fluid_ounce'], cup / 8, namespace=_ns,
doc="U.S. fluid ounce")
def_unit(['tbsp', 'tablespoon'], foz / 2, namespace=_ns,
doc="U.S. customary tablespoon")
def_unit(['tsp', 'teaspoon'], tbsp / 3, namespace=_ns,
doc="U.S. customary teaspoon")
###########################################################################
# MASS
# Imperial measurements
# well, force actually, but who uses it that way?
def_unit(['oz', 'ounce'], 28.349523125 * si.g, namespace=_ns,
doc="International avoirdupois ounce")
def_unit(['lb', 'pound'], 16 * oz, namespace=_ns,
doc="International avoirdupois pound")
def_unit(['ton'], 2000 * lb, namespace=_ns,
doc="International avoirdupois ton")
###########################################################################
# SPEED
def_unit(['kn', 'kt', 'knot', 'NMPH'], nmi / si.h, namespace=_ns,
doc="nautical unit of speed: 1 nmi per hour")
##########################################################################
# ENERGY
def_unit(['BTU', 'btu'], 1.05505585 * si.kJ, namespace=_ns,
doc="British thermal unit")
def_unit(['cal', 'calorie'], 4.184 * si.J, namespace=_ns,
doc="Thermochemical calorie: pre-SI metric unit of energy")
def_unit(['kcal', 'Cal', 'Calorie', 'kilocal', 'kilocalorie'],
1000 * cal, namespace=_ns,
doc="Calorie: colloquial definition of Calorie")
###########################################################################
# POWER
# Imperial units
def_unit(['hp', 'horsepower'], si.W / 0.00134102209, namespace=_ns,
doc="Electrical horsepower")
###########################################################################
# TEMPERATURE
def_unit(['deg_F', 'Fahrenheit'], namespace=_ns, doc='Degrees Fahrenheit',
format={'latex': r'{}^{\circ}F', 'unicode': '°F'})
###########################################################################
# CLEANUP
del UnitBase
del def_unit
###########################################################################
# DOCSTRING
# This generates a docstring for this module that describes all of the
# standard units defined here.
from .utils import generate_unit_summary as _generate_unit_summary
__doc__ += _generate_unit_summary(globals())
[docs]def enable():
"""
Enable Imperial units so they appear in results of
`~astropy.units.UnitBase.find_equivalent_units` and
`~astropy.units.UnitBase.compose`.
This may be used with the ``with`` statement to enable Imperial
units only temporarily.
"""
# Local import to avoid cyclical import
from .core import add_enabled_units
# Local import to avoid polluting namespace
import inspect
return add_enabled_units(inspect.getmodule(enable))