ODEGrowth

class hmf.core.growth_models.ODEGrowth(*, a_min=1e-08, dln_a=0.01)[source]

The growth factor from the linear growth equation, for any FLRW cosmology.

Solves, in ln a,

\[D'' + \left(2 + \frac{d\ln E}{d\ln a}\right) D' - \frac{3}{2}\Omega_m(a) D = 0\]

(e.g. Peebles 1980), with E from astropy (so curvature, radiation, massive neutrinos and w(a) are all included; see background()), by fourth-order Runge-Kutta with step dln_a. It starts at a_min on the growing mode of a matter + radiation universe (Meszaros), \(D \propto 1 + 3a/(2a_{\rm eq})\). The growth rate comes from the solution’s own \(D'/D\).

Parameters:

  • a_min (float, default 1e-08) – The smallest scale factor of the grid; z_max = 1/a_min - 1.

  • dln_a (float, default 0.01) – The spacing of the grid in ln a.

Attributes

a_min: float
alias: ClassVar[str | None] = 'ODE'

The short name the model is registered under, if any. Set by the alias class keyword; never inherited.

backend: ClassVar[str | None] = None

The Boltzmann code that computes the model ("camb" or "class"), if any.

calibration

Where this model was calibrated, with its source (None if it was not).

The class’s calibration_domain, unless it depends on the instance’s parameters.

calibration_domain: ClassVar[Domain | None] = None

The calibration domain of the class, with its source (None if it was not calibrated): that of its default parameters. Ask an instance for calibration.

dln_a: float
parameter_source: ClassVar[str] = ''

The exact source (paper, version, table or equation) of the parameter defaults, e.g. “Tinker et al. 2008, ApJ 688, 709 (published), Table 2”.

references: ClassVar[tuple[str, ...]] = ('Peebles, P. J. E., 1980. The Large-Scale Structure of the Universe. Princeton University Press. https://ui.adsabs.harvard.edu/abs/1980lssu.book.....P',)

References to cite when the model is used, each a formatted citation.

valid_domain: ClassVar[Domain] = Domain(bounds=(('z', Interval(lower=0.0, upper=inf, unit=None, lower_open=False, upper_open=True)),), source='z >= 0.')

z >= 0. The Growth stage checks z against the model’s class’s domain (so a model can narrow it), and also against the redshifts its solution covers (up to GrowthSolution.z_max, e.g. a table’s largest redshift): growth is never extrapolated.

Type:

Where the model can be evaluated

Methods

check_cosmology(cosmology: FLRW) → None

Raise if the model does not apply to cosmology (by default it does).

Raises:

ValueError – If it does not apply: a model that does not apply to a cosmology is a configuration error.

classmethod coerce(value: object) → Self

Convert a value to a model of this kind: the converter of a model field.

Parameters:

value – An instance of cls, which is returned as it is; or a name, import path or class that get() accepts, which is looked up and instantiated with its default parameters.

Returns:

An instance of cls.

Return type:

Model

Raises:

  • ModelNotFoundError – If value is a name that no model of this kind is known by.

  • TypeError – If value is of any other type, or names a class that is not a concrete subclass of cls.

Examples

>>> from hmf.core.filters import Filter, TopHat
>>> Filter.coerce("TopHat") == TopHat()
True
classmethod fields_info() → tuple[FieldInfo, ...]

Describe this class’s fields, without creating an instance.

Returns:

The name, type, default and documentation of each field.

Return type:

tuple of FieldInfo

classmethod get(name: str | type[Model]) → type[Self]

Look up a model of this kind.

Parameters:

name – An alias ("Tinker08"), a qualified name ("hmf.core.fits:Tinker08"), an import path to a class not yet imported ("pkg.mod:Cls" or "pkg.mod.Cls"), or a class.

Returns:

The model class (not an instance). It is always a subclass of cls.

Return type:

type

Raises:

  • ModelNotFoundError – If no model of this kind is known by name, even after loading the hmf.models entry points and trying name as an import path.

  • TypeError – If name resolves to something that is not a concrete subclass of cls.

classmethod get_aliases() → Mapping[str, str]

Return a read-only mapping from alias to qualified name, for this kind.

classmethod get_models() → Mapping[str, type[Self]]

Return the registered models of this kind, by qualified name.

Plugins advertised in the hmf.models entry-point group are loaded first.

Returns:

A read-only mapping from qualified name to class. Called on a kind, it is a live view of the registry. Called on a non-kind subclass, it holds only the models that subclass it.

Return type:

Mapping

classmethod qualified_name() → str

Return this class’s qualified name, package.module:Class.

solve(cosmology: FLRW, *, run: BoltzmannRun | None = None, disk_cache: DiskCache | None = None, k_accuracy: KAccuracy = KAccuracy(dln_k=0.02, ln_k_min=-18.420680743952367, k_max_r_min=20.0)) → GrowthSolution

Compute the growth (see GrowthModel.solve()).

Parameters:
Returns:

The growth of every species.

Return type:

GrowthSolution