Functions
project_to_basis (y3d, edges[, los, poles]) 
Project a 3D statistic on to the specified basis. 
Classes
FFTBase (first, second, Nmesh, BoxSize) 
Base class provides functions for periodic FFT based Power spectrum code. 
FFTPower (first, mode[, Nmesh, BoxSize, …]) 
Algorithm to compute the 1d or 2d power spectrum and/or multipoles in a periodic box, using a Fast Fourier Transform (FFT). 
ProjectedFFTPower (first[, Nmesh, BoxSize, …]) 
The power spectrum of a field in a periodic box, projected over certain axes. 
nbodykit.algorithms.fftpower.
FFTBase
(first, second, Nmesh, BoxSize)[source]¶Base class provides functions for periodic FFT based Power spectrum code.
Parameters: 


Methods
load (output[, comm]) 
Load a saved result. 
save (output) 
Save the result to disk. 
nbodykit.algorithms.fftpower.
FFTPower
(first, mode, Nmesh=None, BoxSize=None, second=None, los=[0, 0, 1], Nmu=5, dk=None, kmin=0.0, kmax=None, poles=[])[source]¶Algorithm to compute the 1d or 2d power spectrum and/or multipoles in a periodic box, using a Fast Fourier Transform (FFT).
This computes the power spectrum as the square of the Fourier modes of the density field, which are computed via a FFT.
Results are computed when the object is inititalized. See the documenation
of run()
for the attributes storing the results.
Note
A full tutorial on the class is available in the documentation here.
Parameters: 


Methods
load (output[, comm]) 
Load a saved result. 
run () 
Compute the power spectrum in a periodic box, using FFTs. 
save (output) 
Save the result to disk. 
load
(output, comm=None)¶Load a saved result. The result has been saved to disk with save()
.
run
()[source]¶Compute the power spectrum in a periodic box, using FFTs.
Returns: 


save
(output)¶Save the result to disk. The format is currently JSON.
nbodykit.algorithms.fftpower.
ProjectedFFTPower
(first, Nmesh=None, BoxSize=None, second=None, axes=(0, 1), dk=None, kmin=0.0)[source]¶The power spectrum of a field in a periodic box, projected over certain axes.
This is not really always physically meaningful, but convenient for making sense of LymanAlpha forest or lensing maps.
This is usually called the 1d power spectrum or 2d power spectrum.
Results are computed when the object is inititalized. See the documenation
of run()
for the attributes storing the results.
Parameters: 


Methods
load (output[, comm]) 
Load a saved result. 
run () 
Run the algorithm. 
save (output) 
Save the result to disk. 
load
(output, comm=None)¶Load a saved result. The result has been saved to disk with save()
.
run
()[source]¶Run the algorithm. This attaches the following attributes to the class:
edges
¶the edges of the wavenumber bins
Type:  array_like 

power
¶a BinnedStatistic object that holds the projected power. It stores the following variables:
k
binType:  BinnedStatistic 

save
(output)¶Save the result to disk. The format is currently JSON.
nbodykit.algorithms.fftpower.
project_to_basis
(y3d, edges, los=[0, 0, 1], poles=[])[source]¶Project a 3D statistic on to the specified basis. The basis will be one of:
Note
The 2D (x, mu) bins will be computed only if poles is specified. See return types for further details.
Notes
Parameters: 


Returns: 
