kspace.PowerSpectrum

class kspace.PowerSpectrum(power_spec_func, ndim=3)

Bases: object

Base class wrapping a user-supplied power spectrum function P(k), with an adjustable normalization.

Parameters:

• power_spec_func (callable) – A function of the wavenumber k returning the (unnormalized) power spectrum. Must be numba-jittable.

• ndim (int, optional) – Number of dimensions (1, 2, or 3). Default is 3.

__init__(power_spec_func, ndim=3)

Methods

A(k)	The Fourier amplitude corresponding to the power spectrum at a given wavenumber k, A(k) = sqrt(E(k) * k).
E(k)	The "energy spectrum" of the power spectrum as a function of the wavenumber k.
__init__(power_spec_func[, ndim])
integrate_E(kmin, kmax)	Integrate the energy spectrum E(k) over a range of wavenumbers.
renormalize(f_rms[, kmin, kmax])	Rescale the power spectrum's normalization so that the integral of its energy spectrum over [kmin, kmax] gives the desired RMS field value.

A(k)

The Fourier amplitude corresponding to the power spectrum at a given wavenumber k, A(k) = sqrt(E(k) * k).

Parameters:

k (float or array-like) – The wavenumber(s).

E(k)

The “energy spectrum” of the power spectrum as a function of the wavenumber k.

Parameters:

k (float or array-like) – The wavenumber(s).

integrate_E(kmin, kmax)

Integrate the energy spectrum E(k) over a range of wavenumbers.

Parameters:

• kmin (float) – The lower wavenumber bound of the integral.

• kmax (float) – The upper wavenumber bound of the integral.

Returns:

The integral of E(k) from kmin to kmax.

Return type:

float

renormalize(f_rms, kmin=0.0, kmax=100.0)

Rescale the power spectrum’s normalization so that the integral of its energy spectrum over [kmin, kmax] gives the desired RMS field value.

Parameters:

• f_rms (float) – The desired RMS value of the field.

• kmin (float, optional) – The lower wavenumber bound of the integral. Default is 0.0.

• kmax (float, optional) – The upper wavenumber bound of the integral. Default is 100.0.