nbodykit.cosmology.power.zeldovich¶

Functions

Classes

class nbodykit.cosmology.power.zeldovich.ZeldovichJ0(k)[source]¶

An integral over \(j_0\) needed to compute the Zeldovich power. The integral is given by:

\[I_0(r) = \int \frac{dk}{2\pi^2} P_L(k) j_0(kr).\]

Methods

__call__(F[, extrap])	Evaluate the integral
check(F)	rough sanity checks on the input function

class nbodykit.cosmology.power.zeldovich.ZeldovichJ1(k)[source]¶

An integral over \(j_1\) needed to compute the Zeldovich power. The integral is given by:

\[I_1(r) = \int \frac{dk}{2\pi^2} P_L(k) \frac{j_1(kr)}{kr}.\]

Methods

__call__(F[, extrap])	Evaluate the integral
check(F)	rough sanity checks on the input function

class nbodykit.cosmology.power.zeldovich.ZeldovichPower(cosmo, redshift, transfer='CLASS')[source]¶

The matter power spectrum in the Zel’dovich approximation.

Parameters:	cosmo (Cosmology) – the cosmology instance z (float) – the redshift of the power spectrum transfer (str, optional) – string specifying the transfer function to use for the linear power spectrum; one of ‘CLASS’, ‘EisensteinHu’, ‘NoWiggleEisensteinHu’

cosmo¶

class:Cosmology, astropy.cosmology.FLRW – the object giving the cosmological parameters

sigma8¶

float – the z=0 amplitude of matter fluctuations

redshift¶

float – the redshift to compute the power at

Plin¶

class:LinearPower – the linear power spectrum class used to compute the Zel’dovich power

Attributes

attrs	The meta-data dictionary
redshift	The redshift of the power spectrum
sigma8	The amplitude of matter fluctuations at \(z=0\).

Methods

__call__(k)

Return the Zel’dovich power in \(h^{-3} \mathrm{Mpc}^3 at :attr:`redshift\) and k, where k is in units of \(h \mathrm{Mpc}^{-1}\).

__call__(k)[source]¶

Return the Zel’dovich power in \(h^{-3} \mathrm{Mpc}^3 at :attr:`redshift\) and k, where k is in units of \(h \mathrm{Mpc}^{-1}\).

Parameters:	k (float, array_like) – the wavenumbers to evaluate the power at

attrs¶

The meta-data dictionary

redshift

The redshift of the power spectrum

sigma8

The amplitude of matter fluctuations at \(z=0\).

class nbodykit.cosmology.power.zeldovich.ZeldovichPowerIntegral(r, n)[source]¶

The integral needed to evaluate the density auto spectrum in the Zel’dovich approximation.

This evaluates:

\[I(k, n) = 4\pi \int dr r^2 \mathrm{exp}\left[-0.5k^2(X(r) + Y(r)) \right] \left (\frac{k Y(r)}{r} \right)^n j_n(kr).\]

Methods

__call__(F[, extrap])	Evaluate the integral
check(F)	rough sanity checks on the input function

nbodykit.cosmology.power.zeldovich.isiterable(obj)[source]¶

Returns True if the given object is iterable.

nbodykit.cosmology.power.zeldovich.vectorize_if_needed(func, *x)[source]¶

Helper function to vectorize functions on array inputs