sarabande 0.0.2

Tool for measuring 3/4 PCFs on discrete periodic data.

A useful python package to measure the 3/4 PCFs of discrete periodic data in $\mathcal{O}(N_g \log N_g)$ time. This is done using Fast Fourier Transforms.

Basic Usage:

import sarabande

NPCF_obj = sarabande.measure(**kwargs)
sarabande.calc_zeta(NPCF_obj)
zeta = NPCF_obj.zeta

Where **kwargs can be any of the arguments to the measure constructor function. The possible arguments are:

Args:

• nPCF ([int]): Must be either 3 or 4. Determines how many points we use in our nPCF.

• projected ([bool]): Flag to determine whether the user wants a projected 3/4 PCF or the Full. Defaults to False.

  • if projected:
    • m_max ([int]): If user chooses projected, we set an m_max (similar to the ell_max in 3D)
  • if not projected:
    • ell_max ([int]): If user choosees not projected (full nPCF) then ell_max is the highest order for calculation.

• density_field_data ([ndarray]): A square ndarray of data that is periodic. Must be 2D for projected and 3D for full.

• save_dir ([string]): A string to tell the algorithm where to save and store files. All temporary files will be stored here.

• save_name ([string]): A string to tell the algorithm what to name the files.

• nbins ([int]): Number of bins to be used in nPCF calculation.

• bin_spacing ([string]): A string to determine the spacing of bins. Options are 'LIN', 'INV', or 'LOG'

• bin_min ([int]): The lower bound of the inner most bin. Default is 1. Optional.

• physical_boxsize ([float]): An optional parameter if using a physical scale. The length of one side of the data.

• rmin ([float]): minimum calculation distance (determins bin_min)

• rmax ([float]): maximum calculation distance (determins bin_max)

Workflow:

The map of SARABANDE is as follows:

For more information about each algorithm, please read (Sunseri et al. 2022)