SMT¶

class hmf.mass_function.fitting_functions.SMT(*args, validate=True, **kwargs)[source]¶

Sheth-Mo-Tormen mass function fit.

For details on attributes, see documentation for BaseFittingFunction.

Parameters:

nu2 (array_like) – A vector of peak-heights, \(\delta_c^2/\sigma^2\) corresponding to m
m (array_like, optional) – A vector of halo masses [units M_sun/h]. Only necessary if req_mass is True. Typically provides limits of applicability. Must correspond to nu2.
z (float, optional) – The redshift. Only used by models that depend on redshift. Default is 0.
n_eff (array_like, optional) – The effective spectral index at m. Only required if req_neff is True.
mass_definition (hmf.halos.mass_definitions.MassDefinition instance) – A halo mass definition. Only required for fits which explicitly include a parameterization for halo definition.
cosmo (astropy.cosmology.FLRW instance, optional) – A cosmology. Default is hmf.cosmology.cosmo.DEFAULT_COSMOLOGY (Planck18), as for the frameworks. Either omegam_z or cosmo is required if req_omz is True. If both are passed, omegam_z takes precedence.
**model_parameters (unpacked-dictionary) – These parameters are model-specific. The available parameters and their defaults are listed in the Notes section of each model (and are also available as <model>._defaults).

Notes

The Sheth-Mo-Tormen [1] form is:

\[f_{\rm SMT}(\sigma) = A\sqrt{2a/\pi}\nu\exp(-a\nu^2/2)(1+(a\nu^2)^{-p})\]

Default model parameters (override them with keyword arguments, or with hmf_params in MassFunction):

References

[1]

Sheth, R. K., Mo, H. J., Tormen, G., May 2001. MNRAS 323 (1), 1-12. http://doi.wiley.com/10.1046/j.1365-8711.2001.04006.x

Attributes

`cutmask`	Boolean mask of the elements within the fit's calibrated range.
`fsigma`	The function \(f(\sigma)\equiv\nu f(\nu)\).
`lnsigma`	Negative log of sigma.
`normalized`	Whether this model is normalized so that all mass is in halos
`nu`	The peak height, \(\nu = \delta_c/\sigma\).
`omegam_z`	Normalised matter density at current redshift.
`references`	References to cite when this model is used, each a formatted citation string.
`req_mass`	Whether m is required for this subclass
`req_neff`	Whether n_eff is required for this subclass
`req_sigma`
`req_z`
`sigma`	The sqrt of mass variance as a function of mass.
`sim_definition`	Details of the defining simulation, instance of `SimDetails`

Methods

classmethod get_measured_mdef()¶: Get the mass definition used in the defining simulation.

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

Get a read-only mapping of all implemented models for this component.

The mapping is a live view of the registry, so it shows models registered later, but it can not be used to add or remove models.