pybird.greenfunction module

class pybird.greenfunction.GreenFunction(Omega0_m, w=None, quintessence=False, Omega0_k=0.0, vectorize=False)

Bases: object

A class to compute cosmological Green’s functions and growth factors.

The GreenFunction class handles calculations related to linear perturbation theory, including growth factors, growth rates, and Green’s functions for different cosmological models (ΛCDM, wCDM, quintessence). It provides the time-dependent functions needed for perturbation theory calculations.

Omega0_m

Present-day matter density parameter.

Type:

float

w

Dark energy equation of state parameter.

Type:

float

quintessence

Whether to include clustering quintessence.

Type:

bool

Omega0_k

Present-day curvature density parameter.

Type:

float

vectorize

Whether to vectorize calculations for arrays of parameters.

Type:

bool

OmegaL_by_Omega_m

Ratio of dark energy to matter density.

Type:

float

wcdm

Whether using wCDM cosmology.

Type:

bool

epsrel

Relative tolerance for numerical integrations.

Type:

float

C()

Compute the time-dependent function C(a) for quintessence models.

H()

Compute the conformal Hubble parameter H(a).

H3()

Compute H(a)^-3.

Omega_m()

Compute the time-dependent matter density parameter Ω_m(a).

D()

Compute the linear growth factor D(a).

DD()

Compute the derivative of the growth factor D’(a).

fplus()

Compute the growth rate f+(a) = aD’(a)/D(a).

Dminus()

Compute the decay factor D-(a).

DDminus()

Compute the derivative of the decay factor D-‘(a).

fminus()

Compute the decay rate f-(a) = aD-‘(a)/D-(a).

W()

Compute the Wronskian W(a) = D’(a)D-(a) - D(a)D-‘(a).

G1d(), G2d(), G1t(), G2t()

Compute Green’s functions for perturbation theory.

I1d(), I2d(), I1t(), I2t()

Compute second order coefficients.

mG1d(), mG2d(), mG1t(), mG2t()

Compute second order time integrals.

G()

Compute quintessence time function.

IU1d(), IU2d(), IU1t(), IU2t()

Compute third order coefficients.

IV11d(), IV12d(), IV21d(), IV22d()

Compute third order coefficients.

IV11t(), IV12t(), IV21t(), IV22t()

Compute third order coefficients.

mU1d(), mU2d(), mU1t(), mU2t()

Compute third order time integrals.

mV11d(), mV12d(), mV21d(), mV22d()

Compute third order time integrals.

mV11t(), mV12t(), mV21t(), mV22t()

Compute third order time integrals.

Y()

Compute third order time function.

C(a)

H(a)

Conformal Hubble

H3(a)

Omega_m(a)

D(a)

Growth factor

DD(a)

Derivative of growth factor

fplus(a)

Growth rate

Dminus(a)

Decay factor

DDminus(a)

Derivative of decay factor

fminus(a)

Decay rate

W(a)

Wronskian

G1d(a, ai)

G2d(a, ai)

G1t(a, ai)

G2t(a, ai)

I1d(ai, a)

I2d(ai, a)

I1t(ai, a)

I2t(ai, a)

mG1d(a)

mG2d(a)

mG1t(a)

mG2t(a)

G(a)

IU1d(ai, a)

IU2d(ai, a)

IU1t(ai, a)

IU2t(ai, a)

IV11d(ai, a)

IV12d(ai, a)

IV21d(ai, a)

IV22d(ai, a)

IV11t(ai, a)

IV12t(ai, a)

IV21t(ai, a)

IV22t(ai, a)

mU1d(a)

mU2d(a)

mU1t(a)

mU2t(a)

mV11d(a)

mV12d(a)

mV21d(a)

mV22d(a)

mV11t(a)

mV12t(a)

mV21t(a)

mV22t(a)

Y(a)