API

Top level user functions to compute power spectra:

GalaxySpectrum([fog_model, use_so_correction]) The model for the galaxy redshift space power spectrum
GalaxySpectrum.initialize() Initialize the underlying splines, etc of the model
GalaxySpectrum.power(k, mu[, flatten]) The total redshift-space galaxy power spectrum at k and mu
GalaxySpectrum.poles(k, ells[, Nmu]) The multipole moments of the redshift-space power spectrum
GalaxySpectrum.from_transfer

Loading GalaxySpectrum objects from and saving to pickle files:

GalaxySpectrum.to_npy(filename) Save to a .npy file by calling numpy.save()
GalaxySpectrum.from_npy(filename) Load a model from a .npy file

Generating the default set of parameters for fitting the GalaxySpectrum to data:

GalaxySpectrum.default_params() A GalaxyPowerParameters object holding the default model parameters

Evaluating power spectra with an additional transfer function, i.e., on a discrete (k, mu) grid or convolved with a window:

PkmuGrid
PkmuTransfer
PolesTransfer
pyRSD.rsd.window.WindowTransfer

The GalaxySpectrum Class

class pyRSD.rsd.GalaxySpectrum(fog_model='modified_lorentzian', use_so_correction=False, **kwargs)

The model for the galaxy redshift space power spectrum

Parameters:

kmin : float, optional

The minimum wavenumber to compute the power spectrum at [units: \(h/\mathrm{Mpc}\)]; default is 1e-3

kmax : float, optional

The maximum wavenumber to compute the power spectrum at [units: \(h/\mathrm{Mpc}\)]; default is 0.5

Nk : int, optional

The number of log-spaced bins to use as the underlying domain for splines; default is 200

z : float, optional

The redshift to compute the power spectrum at. Default = 0.

params : Cosmology, str

Either a Cosmology instance or the name of a file to load parameters from; see the ‘data/params’ directory for examples

include_2loop : bool, optional

If True, include 2-loop contributions in the model terms. Default is False.

transfer_fit : str, optional

The name of the transfer function fit to use. Default is CLASS and the options are {CLASS, EH, EH_NoWiggle, BBKS}, or the name of a data file holding (k, T(k))

max_mu : {0, 2, 4, 6, 8}, optional

Only compute angular terms up to mu**(max_mu). Default is 4.

interpolate: bool, optional

Whether to return interpolated results for underlying power moments

k0_low : float, optional (5e-3)

below this wavenumber, evaluate any power in “low-k mode”, which essentially just uses SPT at low-k

linear_power_file : str, optional (None)

string specifying the name of a file which gives the linear power spectrum, from which the transfer function in cosmo will be initialized

Pdv_model_type : {‘jennings’, ‘sim’, None}, optional

The type of model to use to evaluate Pdv

fog_model : str, optional

the string specifying the FOG model to use; one of [‘modified_lorentzian’, ‘lorentzian’, ‘gaussian’]. Default is ‘modified_lorentzian’

use_so_correction : bool, optional

Boost the centrals auto spectrum with a correction accounting for extra structure around centrals due to SO halo finders; default is False
power(k, mu, flatten=False)

The total redshift-space galaxy power spectrum at k and mu

Parameters:

k : float, array_like

The wavenumbers to evaluate the power spectrum at, in h/Mpc

mu : float, array_like

The cosine of the angle from the line of sight. If a float is provided, the value is used for all input k values. If array-like and mu has the same shape as k, the power at each (k,mu) pair is returned. If mu has a shape different than k, the returned power has shape (len(k), len(mu)).

flatten : bool, optional

If True, flatten the return array, which will have a length of len(k) * len(mu)
default_params()

A GalaxyPowerParameters object holding the default model parameters

The model associated with the parameter is self

poles(k, ells, Nmu=40)

The multipole moments of the redshift-space power spectrum

Parameters:

k : float, array_like

The wavenumbers to evaluate the power spectrum at, in h/Mpc

ells : int, array_like

The ell values of the multipole moments

Nmu : int, optional

the number of mu bins to use when performing the multipole integration
Returns:

poles : array_like

returns tuples of arrays for each ell value in poles

Gridded Power Spectra

Window-convolved Power Spectra