densitysplit package

Submodules

densitysplit.cosmology module

class densitysplit.cosmology.Cosmology(omega_m=0.308, h=0.676, c=299792.458)

Bases: object

Class for cosmology calculations.

Parameters:

  • omega_m (float, optional) – Matter density parameter.

  • h (float, optional) – Hubble parameter.

  • c (float, optional) – Speed of light in km/s.

H0

Hubble constant in km/s/Mpc.

Type:

float

h

Dimensionless Hubble parameter.

Type:

float

c

Speed of light in km/s.

Type:

float

omega_m

Matter density parameter.

Type:

float

omega_lambda

Dark energy density parameter.

Type:

float

zgrid

Redshift grid used for interpolation.

Type:

array_like

rgrid

Comoving distance grid used for interpolation.

Type:

array_like

AngularDiameterDistance(z)

Calculate angular diameter distance as a function of redshift.

Parameters:

z (float) – Redshift.

Returns:

Angular diameter distance in Mpc/h.

Return type:

float

ComovingDistance(z)

Calculate comoving distance as a function of redshift.

Parameters:

z (float) – Redshift.

Returns:

Comoving distance in Mpc/h.

Return type:

float

Ez(z)
GrowthFactor(z)

Calculate linear growth factor as a function of redshift.

Parameters:

z (float) – Redshift.

Returns:

Linear growth factor.

Return type:

float

GrowthRate(z)

Calculate linear growth rate as a function of redshift.

Parameters:

z (float) – Redshift.

Returns:

Linear growth rate.

Return type:

float

HubbleParameter(z)

Calculate Hubble parameter as a function of redshift.

Parameters:

z (float) –

Redshift.

returns:

  • float

  • Hubble parameter in units of 100 km/s/Mpc.

Redshift(r)

Calculate redshift as a function of comoving distance.

Parameters:

r (float) – Comoving distance in Mpc/h.

Returns:

Redshift.

Return type:

float

densitysplit.filters module

class densitysplit.filters.Gaussian(r)

Bases: object

Gaussian filter in Fourier space

Parameters:

r (float) – the radius of the Gaussian filter

class densitysplit.filters.TopHat(r)

Bases: object

Top-hat filter in Fourier space adapted from https://github.com/bccp/nbodykit/

Parameters:

r (float) – the radius of the top-hat filter

densitysplit.pipeline module

class densitysplit.pipeline.DensitySplit(data_positions, boxsize=None, data_weights=None, randoms_positions=None, randoms_weights=None)

Bases: object

Class to split a set of points into quantiles based on the local density field.

Parameters:

  • data_positions (array_like) – Positions of the data points.

  • boxsize (float, optional) – Size of the box. If not provided, randoms are required.

  • data_weights (array_like, optional) – Weights of the data points. If not provided, all points are assumed to have the same weight.

  • randoms_positions (array_like, optional) – Positions of the random points. If not provided, boxsize must be provided.

  • randoms_weights (array_like, optional) – Weights of the random points. If not provided, all points are assumed to have the same weight.

data_positions

Positions of the data points.

Type:

array_like

boxsize

Size of the box.

Type:

float

data_weights

Weights of the data points.

Type:

array_like

randoms_positions

Positions of the random points.

Type:

array_like

randoms_weights

Weights of the random points.

Type:

array_like

mesh

CatalogMesh object.

Type:

CatalogMesh

density

Density field at the sampling positions.

Type:

array_like

sampling_positions

Positions where the density field was sampled.

Type:

array_like

get_box_randoms(nrandoms, seed=42)

Get random points inside the box.

Parameters:

  • nrandoms (int) – Number of random points to generate.

  • seed (int, optional) – Random seed.

Returns:

randoms – Random points inside the box.

Return type:

array_like

get_density_mesh(smooth_radius, cellsize, compensate=False, resampler='cic', interlacing=0, sampling='randoms', sampling_positions=None, boxpad=2.0, filter_shape='TopHat', ran_min=0.01)

Get the overdensity field.

Parameters:

  • smooth_radius (float) – Radius of the smoothing filter.

  • cellsize (float) – Size of the cells in the mesh.

  • compensate (bool, optional) – Compensate for the shot noise.

  • resampler (str, optional) – Resampling method.

  • interlacing (int, optional) – Interlacing order.

  • sampling (str, optional) – Sampling method.

  • sampling_positions (array_like, optional) – Positions where the density field should be sampled. If not provided, the randoms are used.

  • boxpad (float, optional) – Padding of the box.

  • filter_shape (str, optional) – Shape of the smoothing filter.

Returns:

  • density (array_like) – Density field at the sampling positions.

  • sampling_positions (array_like) – Positions where the density field was sampled.

get_density_paircount(smooth_radius, sampling_positions, filter_shape='Tophat', nthreads=1)

Get the overdensity field using pair counting.

Parameters:

  • smooth_radius (float) – Radius of the smoothing filter.

  • sampling_positions (array_like) – Positions where the density field should be sampled.

  • filter_shape (str, optional) – Shape of the smoothing filter.

  • nthreads (int, optional) – Number of threads to use.

Returns:

density – Density field at the sampling positions.

Return type:

array_like

get_mesh()

Get the CatalogMesh object.

Returns:

mesh – CatalogMesh object.

Return type:

CatalogMesh

get_quantiles(nquantiles, return_idx=False)

Get the quantiles of the density field.

Parameters:

  • nquantiles (int) – Number of quantiles.

  • return_idx (bool, optional) – Whether to return index of the quantile of each query point.

Returns:

  • quantiles (array_like) – Quantiles of the density field.

  • quantiles_idx (array_like, optional) – Index of the quantile of each query point.

densitysplit.utilities module

densitysplit.utilities.cartesian_to_sky(data, cosmology)

Converts cartesian coordinates to ra, dec, redshift.

Parameters:

  • data (array_like) – Array of x, y, z coordinates.

  • cosmology (Cosmology) – Cosmology object.

Returns:

cout – Array of ra, dec, redshift.

Return type:

array_like

densitysplit.utilities.sky_to_cartesian(data, cosmology)

Converts ra, dec, redshift to cartesian coordinates.

Parameters:

  • data (array_like) – Array of ra, dec, redshift.

  • cosmology (Cosmology) – Cosmology object.

Returns:

cout – Array of x, y, z coordinates.

Return type:

array_like

Module contents