def test_Parameter_init_deprecated_fmt(self):
"""Test that passing the argument ``fmt`` is deprecated."""
with pytest.warns(AstropyDeprecationWarning):
parameter = Parameter(fmt=".4f")
assert parameter._format_spec == ".4f"
# Test that it appears in initializing arguments
init_args = parameter._get_init_arguments()
assert init_args["fmt"] == ".4f"
def test_Parameter_validator(self, param):
"""Test :meth:`astropy.cosmology.Parameter.validator`."""
for k in Parameter._registry_validators:
newparam = param.validator(k)
assert newparam.fvalidate == newparam._registry_validators[k]
# error for non-registered str
with pytest.raises(ValueError, match="`fvalidate`, if str"):
Parameter(fvalidate="NOT REGISTERED")
# error if wrong type
with pytest.raises(TypeError, match="`fvalidate` must be a function or"):
Parameter(fvalidate=object())
def test_Parameter_equality(self):
"""
Test Parameter equality.
Determined from the processed initialization args (including defaults).
"""
p1 = Parameter(unit="km / (s Mpc)")
p2 = Parameter(unit="km / (s Mpc)")
assert p1 == p2
# not equal parameters
p3 = Parameter(unit="km / s")
assert p3 != p1
# misc
assert p1 != 2 # show doesn't error
class SubCosmology(Cosmology):
"""Defined here to be serializable."""
H0 = Parameter(unit="km/(s Mpc)")
Tcmb0 = Parameter(unit=u.K)
m_nu = Parameter(unit=u.eV)
def __init__(self, H0, Tcmb0=0*u.K, m_nu=0*u.eV, name=None, meta=None):
super().__init__(name=name, meta=meta)
self.H0 = H0
self.Tcmb0 = Tcmb0
self.m_nu = m_nu
@property
def is_flat(self):
return super().is_flat()
class ExampleBase:
def __init__(self, param=15):
self._param = param
sig = inspect.signature(__init__)
_init_signature = sig.replace(parameters=list(sig.parameters.values())[1:])
param = Parameter(doc="example parameter")
def test_Parameter_init(self):
"""Test :class:`astropy.cosmology.Parameter` instantiation."""
# defaults
parameter = Parameter()
assert parameter.fvalidate is _validate_with_unit
assert parameter.unit is None
assert parameter.equivalencies == []
assert parameter.derived is False
assert parameter.name is None
# setting all kwargs
parameter = Parameter(fvalidate="float", doc="DOCSTRING", unit="km",
equivalencies=[u.mass_energy()], derived=True)
assert parameter.fvalidate is _validate_to_float
assert parameter.unit is u.km
assert parameter.equivalencies == [u.mass_energy()]
assert parameter.derived is True
class Example(cosmo_cls):
param = Parameter(unit=u.eV, equivalencies=u.mass_energy())
def __init__(self, param, *, name=None, meta=None):
self.param = param
@property
def is_flat(self):
return super().is_flat()
class Example1(Cosmology):
param = Parameter(doc="Description of example parameter.",
unit=u.m, equivalencies=u.mass_energy())
def __init__(self, param=15):
self.param = param
@property
def is_flat(self):
return super().is_flat()
class wCDM(FLRW):
"""
FLRW cosmology with a constant dark energy equation of state and curvature.
This has one additional attribute beyond those of FLRW.
Parameters
----------
H0 : float or scalar quantity-like ['frequency']
Hubble constant at z = 0. If a float, must be in [km/sec/Mpc].
Om0 : float
Omega matter: density of non-relativistic matter in units of the
critical density at z=0.
Ode0 : float
Omega dark energy: density of dark energy in units of the critical
density at z=0.
w0 : float, optional
Dark energy equation of state at all redshifts. This is
pressure/density for dark energy in units where c=1. A cosmological
constant has w0=-1.0.
Tcmb0 : float or scalar quantity-like ['temperature'], optional
Temperature of the CMB z=0. If a float, must be in [K]. Default: 0 [K].
Setting this to zero will turn off both photons and neutrinos
(even massive ones).
Neff : float, optional
Effective number of Neutrino species. Default 3.04.
m_nu : quantity-like ['energy', 'mass'] or array-like, optional
Mass of each neutrino species in [eV] (mass-energy equivalency enabled).
If this is a scalar Quantity, then all neutrino species are assumed to
have that mass. Otherwise, the mass of each species. The actual number
of neutrino species (and hence the number of elements of m_nu if it is
not scalar) must be the floor of Neff. Typically this means you should
provide three neutrino masses unless you are considering something like
a sterile neutrino.
Ob0 : float or None, optional
Omega baryons: density of baryonic matter in units of the critical
density at z=0. If this is set to None (the default), any computation
that requires its value will raise an exception.
name : str or None (optional, keyword-only)
Name for this cosmological object.
meta : mapping or None (optional, keyword-only)
Metadata for the cosmology, e.g., a reference.
Examples
--------
>>> from astropy.cosmology import wCDM
>>> cosmo = wCDM(H0=70, Om0=0.3, Ode0=0.7, w0=-0.9)
The comoving distance in Mpc at redshift z:
>>> z = 0.5
>>> dc = cosmo.comoving_distance(z)
"""
w0 = Parameter(doc="Dark energy equation of state.", fvalidate="float")
def __init__(self,
H0,
Om0,
Ode0,
w0=-1.0,
Tcmb0=0.0 * u.K,
Neff=3.04,
m_nu=0.0 * u.eV,
Ob0=None,
*,
name=None,
meta=None):
super().__init__(H0=H0,
Om0=Om0,
Ode0=Ode0,
Tcmb0=Tcmb0,
Neff=Neff,
m_nu=m_nu,
Ob0=Ob0,
name=name,
meta=meta)
self.w0 = w0
# Please see :ref:`astropy-cosmology-fast-integrals` for discussion
# about what is being done here.
if self._Tcmb0.value == 0:
self._inv_efunc_scalar = scalar_inv_efuncs.wcdm_inv_efunc_norel
self._inv_efunc_scalar_args = (self._Om0, self._Ode0, self._Ok0,
self._w0)
elif not self._massivenu:
self._inv_efunc_scalar = scalar_inv_efuncs.wcdm_inv_efunc_nomnu
self._inv_efunc_scalar_args = (self._Om0, self._Ode0, self._Ok0,
self._Ogamma0 + self._Onu0,
self._w0)
else:
self._inv_efunc_scalar = scalar_inv_efuncs.wcdm_inv_efunc
self._inv_efunc_scalar_args = (self._Om0, self._Ode0, self._Ok0,
self._Ogamma0, self._neff_per_nu,
self._nmasslessnu, self._nu_y_list,
self._w0)
def w(self, z):
r"""Returns dark energy equation of state at redshift ``z``.
Parameters
----------
z : Quantity-like ['redshift'], array-like, or `~numbers.Number`
Input redshift.
Returns
-------
w : ndarray or float
The dark energy equation of state
Returns `float` if the input is scalar.
Notes
-----
The dark energy equation of state is defined as
:math:`w(z) = P(z)/\rho(z)`, where :math:`P(z)` is the pressure at
redshift z and :math:`\rho(z)` is the density at redshift z, both in
units where c=1. Here this is :math:`w(z) = w_0`.
"""
z = aszarr(z)
return self._w0 * (np.ones(z.shape) if hasattr(z, "shape") else 1.0)
def de_density_scale(self, z):
r"""Evaluates the redshift dependence of the dark energy density.
Parameters
----------
z : Quantity-like ['redshift'], array-like, or `~numbers.Number`
Input redshift.
Returns
-------
I : ndarray or float
The scaling of the energy density of dark energy with redshift.
Returns `float` if the input is scalar.
Notes
-----
The scaling factor, I, is defined by :math:`\rho(z) = \rho_0 I`,
and in this case is given by
:math:`I = \left(1 + z\right)^{3\left(1 + w_0\right)}`
"""
return (aszarr(z) + 1.0)**(3.0 * (1. + self._w0))
def efunc(self, z):
"""Function used to calculate H(z), the Hubble parameter.
Parameters
----------
z : Quantity-like ['redshift'], array-like, or `~numbers.Number`
Input redshift.
Returns
-------
E : ndarray or float
The redshift scaling of the Hubble constant.
Returns `float` if the input is scalar.
Defined such that :math:`H(z) = H_0 E(z)`.
"""
Or = self._Ogamma0 + (self._Onu0 if not self._massivenu else
self._Ogamma0 * self.nu_relative_density(z))
zp1 = aszarr(z) + 1.0 # (converts z [unit] -> z [dimensionless])
return sqrt(zp1**2 * ((Or * zp1 + self._Om0) * zp1 + self._Ok0) +
self._Ode0 * zp1**(3. * (1. + self._w0)))
def inv_efunc(self, z):
r"""Function used to calculate :math:`\frac{1}{H_z}`.
Parameters
----------
z : Quantity-like ['redshift'], array-like, or `~numbers.Number`
Input redshift.
Returns
-------
E : ndarray or float
The inverse redshift scaling of the Hubble constant.
Returns `float` if the input is scalar.
Defined such that :math:`H_z = H_0 / E`.
"""
Or = self._Ogamma0 + (self._Onu0 if not self._massivenu else
self._Ogamma0 * self.nu_relative_density(z))
zp1 = aszarr(z) + 1.0 # (converts z [unit] -> z [dimensionless])
return (zp1**2 * ((Or * zp1 + self._Om0) * zp1 + self._Ok0) +
self._Ode0 * zp1**(3. * (1. + self._w0)))**(-0.5)
def test_Parameter_repr_roundtrip(self, param):
"""Test ``eval(repr(Parameter))`` can round trip to ``Parameter``."""
P = Parameter(doc="A description of this parameter.", derived=True)
NP = eval(repr(P)) # Evaluate string representation back into a param.
assert P == NP
class Example(cosmo_cls):
param = Parameter()
def __init__(self, param, *, name=None, meta=None):
pass # never actually initialized
class ExampleBase(cosmo_cls):
param = Parameter()
class w0waCDM(FLRW):
r"""FLRW cosmology with a CPL dark energy equation of state and curvature.
The equation for the dark energy equation of state uses the
CPL form as described in Chevallier & Polarski [1]_ and Linder [2]_:
:math:`w(z) = w_0 + w_a (1-a) = w_0 + w_a z / (1+z)`.
Parameters
----------
H0 : float or scalar quantity-like ['frequency']
Hubble constant at z = 0. If a float, must be in [km/sec/Mpc].
Om0 : float
Omega matter: density of non-relativistic matter in units of the
critical density at z=0.
Ode0 : float
Omega dark energy: density of dark energy in units of the critical
density at z=0.
w0 : float, optional
Dark energy equation of state at z=0 (a=1). This is pressure/density
for dark energy in units where c=1.
wa : float, optional
Negative derivative of the dark energy equation of state with respect
to the scale factor. A cosmological constant has w0=-1.0 and wa=0.0.
Tcmb0 : float or scalar quantity-like ['temperature'], optional
Temperature of the CMB z=0. If a float, must be in [K]. Default: 0 [K].
Setting this to zero will turn off both photons and neutrinos
(even massive ones).
Neff : float, optional
Effective number of Neutrino species. Default 3.04.
m_nu : quantity-like ['energy', 'mass'] or array-like, optional
Mass of each neutrino species in [eV] (mass-energy equivalency enabled).
If this is a scalar Quantity, then all neutrino species are assumed to
have that mass. Otherwise, the mass of each species. The actual number
of neutrino species (and hence the number of elements of m_nu if it is
not scalar) must be the floor of Neff. Typically this means you should
provide three neutrino masses unless you are considering something like
a sterile neutrino.
Ob0 : float or None, optional
Omega baryons: density of baryonic matter in units of the critical
density at z=0. If this is set to None (the default), any computation
that requires its value will raise an exception.
name : str or None (optional, keyword-only)
Name for this cosmological object.
meta : mapping or None (optional, keyword-only)
Metadata for the cosmology, e.g., a reference.
Examples
--------
>>> from astropy.cosmology import w0waCDM
>>> cosmo = w0waCDM(H0=70, Om0=0.3, Ode0=0.7, w0=-0.9, wa=0.2)
The comoving distance in Mpc at redshift z:
>>> z = 0.5
>>> dc = cosmo.comoving_distance(z)
References
----------
.. [1] Chevallier, M., & Polarski, D. (2001). Accelerating Universes with
Scaling Dark Matter. International Journal of Modern Physics D,
10(2), 213-223.
.. [2] Linder, E. (2003). Exploring the Expansion History of the
Universe. Phys. Rev. Lett., 90, 091301.
"""
w0 = Parameter(doc="Dark energy equation of state at z=0.",
fvalidate="float")
wa = Parameter(
doc="Negative derivative of dark energy equation of state w.r.t. a.",
fvalidate="float")
def __init__(self,
H0,
Om0,
Ode0,
w0=-1.0,
wa=0.0,
Tcmb0=0.0 * u.K,
Neff=3.04,
m_nu=0.0 * u.eV,
Ob0=None,
*,
name=None,
meta=None):
super().__init__(H0=H0,
Om0=Om0,
Ode0=Ode0,
Tcmb0=Tcmb0,
Neff=Neff,
m_nu=m_nu,
Ob0=Ob0,
name=name,
meta=meta)
self.w0 = w0
self.wa = wa
# Please see :ref:`astropy-cosmology-fast-integrals` for discussion
# about what is being done here.
if self._Tcmb0.value == 0:
self._inv_efunc_scalar = scalar_inv_efuncs.w0wacdm_inv_efunc_norel
self._inv_efunc_scalar_args = (self._Om0, self._Ode0, self._Ok0,
self._w0, self._wa)
elif not self._massivenu:
self._inv_efunc_scalar = scalar_inv_efuncs.w0wacdm_inv_efunc_nomnu
self._inv_efunc_scalar_args = (self._Om0, self._Ode0, self._Ok0,
self._Ogamma0 + self._Onu0,
self._w0, self._wa)
else:
self._inv_efunc_scalar = scalar_inv_efuncs.w0wacdm_inv_efunc
self._inv_efunc_scalar_args = (self._Om0, self._Ode0, self._Ok0,
self._Ogamma0, self._neff_per_nu,
self._nmasslessnu, self._nu_y_list,
self._w0, self._wa)
def w(self, z):
r"""Returns dark energy equation of state at redshift ``z``.
Parameters
----------
z : Quantity-like ['redshift'], array-like, or `~numbers.Number`
Input redshift.
Returns
-------
w : ndarray or float
The dark energy equation of state
Returns `float` if the input is scalar.
Notes
-----
The dark energy equation of state is defined as
:math:`w(z) = P(z)/\rho(z)`, where :math:`P(z)` is the pressure at
redshift z and :math:`\rho(z)` is the density at redshift z, both in
units where c=1. Here this is
:math:`w(z) = w_0 + w_a (1 - a) = w_0 + w_a \frac{z}{1+z}`.
"""
z = aszarr(z)
return self._w0 + self._wa * z / (z + 1.0)
def de_density_scale(self, z):
r"""Evaluates the redshift dependence of the dark energy density.
Parameters
----------
z : Quantity-like ['redshift'], array-like, or `~numbers.Number`
Input redshift.
Returns
-------
I : ndarray or float
The scaling of the energy density of dark energy with redshift.
Returns `float` if the input is scalar.
Notes
-----
The scaling factor, I, is defined by :math:`\rho(z) = \rho_0 I`,
and in this case is given by
.. math::
I = \left(1 + z\right)^{3 \left(1 + w_0 + w_a\right)}
\exp \left(-3 w_a \frac{z}{1+z}\right)
"""
z = aszarr(z)
zp1 = z + 1.0 # (converts z [unit] -> z [dimensionless])
return zp1**(3 *
(1 + self._w0 + self._wa)) * exp(-3 * self._wa * z / zp1)
