def ureg(**defaults):
if ureg_singleton.ureg is None:
u = ureg_singleton.ureg = UnitRegistry()
else:
return ureg_singleton.ureg
u.define('Msun = 1.99885e30kg')
u.define("hubble = [hubbli]")
u.define("scalefactor = [scalefactori]")
u.define('gmass = 1e10 Msun/hubble')
u.define('cmass = Msun/hubble')
u.define('clength = kpc/hubble*scalefactor')
u.define('glength = clength')
u.define('cvelocity = scalefactor*km/s')
u.define('gvelocity_a = (scalefactor**0.5)km/s')
u.define('gvelocity_noa = km/s')
c = Context('comoving', defaults={"hubble": None, "scalefactor": None})
def f_1(u, v, hubble=None, scalefactor=None):
m = v.to(u.clength).magnitude
if hubble is not None and scalefactor is not None:
return u.kpc * m * scalefactor / hubble
else:
raise Exception("hubble=%s, scalefactor=%s" %
(str(hubble), str(scalefactor)))
def g_1(u, v, hubble=None, scalefactor=None):
m = v.to(u.cmass).magnitude
if hubble is not None:
return u.Msun * m / hubble
else:
raise Exception("hubble=%s " % (str(hubble)))
def f_2(u, v, hubble=None, scalefactor=None):
m = v.to(u.kpc).magnitude
if hubble is not None and scalefactor is not None:
return u.clength / scalefactor * hubble
else:
raise Exception("hubble=%s, scalefactor=%s" %
(str(hubble), str(scalefactor)))
c.add_transformation('[length] * [scalefactori] / [hubbli]', '[length]',
f_1)
c.add_transformation('[length]', '[length] * [scalefactori] / [hubbli]',
f_2)
c.add_transformation('[mass] / [hubbli]', '[mass]', g_1)
u.add_context(c)
#if(len(defaults)>0):
# u.enable_contexts(c,**defaults)
u.enable_contexts(c, hubble=.704)
return u
# -*- coding: utf-8 -*-
"""Various units-related things
This module has a soft dependency on the pint units library. Please
import this module only conditionally or only if you can accept a pint
dependency.
"""
from pint import (UnitRegistry, Context)
ureg = UnitRegistry()
ureg.define("micro- = 1e-6 = µ-")
# aid conversion between different radiance units
sp2 = Context("radiance")
sp2.add_transformation(
"[length] * [mass] / [time] ** 3",
"[mass] / [time] ** 2",
lambda ureg, x: x / ureg.speed_of_light)
sp2.add_transformation(
"[mass] / [time] ** 2",
"[length] * [mass] / [time] ** 3",
lambda ureg, x: x * ureg.speed_of_light)
ureg.add_context(sp2)
radiance_units = {
"si": ureg.W / (ureg.m**2 * ureg.sr * ureg.Hz),
"ir": ureg.mW / (ureg.m**2 * ureg.sr * (1 / ureg.cm))}
def set_nmr_context(larmor):
"""
Set a NMR context relative to the given Larmor frequency.
Parameters
----------
larmor : |Quantity| or float
The Larmor frequency of the current nucleus.
If it is not a quantity it is assumed to be given in MHz.
Examples
--------
First we set the NMR context,
>>> from spectrochempy.core.units import ur, set_nmr_context
>>>
>>> set_nmr_context(104.3 * ur.MHz)
then, we can use the context as follow
>>> fhz = 10000 * ur.Hz
>>> with ur.context('nmr'):
... fppm = fhz.to('ppm')
>>> print("{:~.3f}".format(fppm))
95.877 ppm
or in the opposite direction
>>> with ur.context('nmr'):
... fhz = fppm.to('kHz')
>>> print("{:~.3f}".format(fhz))
10.000 kHz
Now we update the context :
>>> with ur.context('nmr', larmor=100. * ur.MHz):
... fppm = fhz.to('ppm')
>>> print("{:~.3f}".format(fppm))
100.000 ppm
>>> set_nmr_context(75 * ur.MHz)
>>> fhz = 10000 * ur.Hz
>>> with ur.context('nmr'):
... fppm = fhz.to('ppm')
>>> print("{:~.3f}".format(fppm))
133.333 ppm
"""
if not isinstance(larmor, U_.Quantity):
larmor = larmor * U_.MHz
if "nmr" not in list(U_._contexts.keys()):
c = Context("nmr", defaults={"larmor": larmor})
c.add_transformation(
"[]",
"[frequency]",
lambda U_, x, **kwargs: x * kwargs.get("larmor") / 1.0e6,
)
c.add_transformation(
"[frequency]",
"[]",
lambda U_, x, **kwargs: x * 1.0e6 / kwargs.get("larmor"),
)
U_.add_context(c)
else:
c = U_._contexts["nmr"]
c.defaults["larmor"] = larmor
from pint import (UnitRegistry, Context)
__all__ = [
'ureg',
'radiance_units',
]
ureg = UnitRegistry()
ureg.define("micro- = 1e-6 = µ-")
# aid conversion between different radiance units
sp2 = Context("radiance")
# specrad per frequency → specrad per wavenumber
sp2.add_transformation(
"[length] * [mass] / [time] ** 3",
"[mass] / [time] ** 2",
lambda ureg, x, **kwargs: x / ureg.speed_of_light)
# specrad per wavenumber → specrad per frequency
sp2.add_transformation(
"[mass] / [time] ** 2",
"[length] * [mass] / [time] ** 3",
lambda ureg, x, **kwargs: x * ureg.speed_of_light)
#sp2.add_transformation(
# "[mass] / ([length] * [time] ** 3)",
# "[length] * [mass] / [time] ** 3",
# lambda ureg, x, **kwargs: )
def _R_to_bt(ureg, R, srf):
"""For use by pint, do not call directly, use q.to or SRF class."""
if srf.lookup_table is None:
srf.make_lookup_table()
return ureg.Quantity(srf.L_to_T(R), 'K')
# -*- coding: utf-8 -*-
"""
Created on Fri Jul 29 11:15:57 2016
@author: Arno Rehn
"""
from pint import Context
from common import ureg
# Create and enable a THz-TDS context where we can convert times to lengths
# and vice-versa
thz_context = Context('terahertz')
thz_context.add_transformation('[time]', '[length]',
lambda ureg, x: ureg.speed_of_light * x / 2)
thz_context.add_transformation('[length]', '[time]',
lambda ureg, x: 2 * x / ureg.speed_of_light)
thz_context.add_transformation('', '[length]/[time]',
lambda ureg, x: ureg.speed_of_light * x / 2)
thz_context.add_transformation('[length]/[time]', '',
lambda ureg, x: 2 * x / ureg.speed_of_light)
ureg.add_context(thz_context)
ureg.enable_contexts('terahertz')
def set_nmr_context(larmor):
"""
Set a NMR context relative to the given Larmor frequency
Parameters
----------
larmor : Quantity or float
The Larmor frequency of the current nucleus.
If it is not a quantity it is assumed to be given in MHz
Examples
--------
First we set the NMR context,
>>> set_nmr_context(104.3 * U_.MHz)
then, we can use the context as follow :
>>> fhz = 10000 * U_.Hz
>>> with U_.context('nmr'):
... fppm = fhz.to('ppm')
>>> print("{:~.3f}".format(fppm))
95.877 ppm
or in the opposite direction
>>> with U_.context('nmr'):
... fhz = fppm.to('kHz')
>>> print("{:~.3f}".format(fhz))
10.000 kHz
Now we update the context :
>>> with U_.context('nmr', larmor=100. * U_.MHz):
... fppm = fhz.to('ppm')
>>> print("{:~.3f}".format(fppm))
100.000 ppm
>>> set_nmr_context(75 * U_.MHz)
>>> fhz = 10000 * U_.Hz
>>> with U_.context('nmr'):
... fppm = fhz.to('ppm')
>>> print("{:~.3f}".format(fppm))
133.333 ppm
"""
if not isinstance(larmor, U_.Quantity):
larmor = larmor * U_.MHz
if 'nmr' not in list(U_._contexts.keys()):
c = Context('nmr', defaults={'larmor': larmor})
c.add_transformation('[]', '[frequency]', lambda U_, x, **kwargs: x * kwargs.get('larmor') / 1.e6)
c.add_transformation('[frequency]', '[]', lambda U_, x, **kwargs: x * 1.e6 / kwargs.get('larmor'))
U_.add_context(c)
else:
c = U_._contexts['nmr']
c.defaults['larmor'] = larmor
unit_registry.define("d = day")
unit_registry.define("degreeC = degC")
unit_registry.define("degreeF = degF")
unit_registry.define(
"kt = 1000 * t") # since kt is used for "knot" in the defaults
unit_registry.define("ppt = [concentrations]")
unit_registry.define("ppb = 1000 * ppt")
unit_registry.define("ppm = 1000 * ppb")
# Contexts:
_c = Context("AR4GWP12")
_c.add_transformation(
"[carbon]",
"[nitrogen]",
lambda unit_registry, x: 20 * unit_registry.N * x / unit_registry.C,
)
_c.add_transformation(
"[nitrogen]",
"[carbon]",
lambda unit_registry, x: x * unit_registry.C / unit_registry.N / 20,
)
unit_registry.add_context(_c)
_ch4_context = Context("CH4_conversions")
_ch4_context.add_transformation(
"[carbon]",
"[methane]",
lambda unit_registry, x: 16 / 12 * unit_registry.CH4 * x / unit_registry.C,
)
