pyselfi_examples.grf.model.blackbox_GRF module

A blackbox to generate Gaussian random fields and evaluate their power spectrum, using the Simbelmynë code.

class pyselfi_examples.grf.model.blackbox_GRF.blackbox(P, **kwargs)[source]

Bases: object

This class represents a SELFI blackbox.

Variables

  • P (int) – number of output summary statistics. This is the only mandatory argument

  • theta2P (func) – function to go from input parameters theta to cosmological power spectrum

  • k_s (array, double, dimension=S) – vector of support wavenumbers

  • G_sim (FourierGrid) – Fourier grid of the simulation

  • P_ss (PowerSpectrum) – fiducial summaries at the expansion point, to normalize the output of the blackbox

  • corner0 (double) – x-position of the corner of the box with respect to the observer (which is at (0,0,0))

  • corner1 (double) – y-position of the corner of the box with respect to the observer (which is at (0,0,0))

  • corner2 (double) – z-position of the corner of the box with respect to the observer (which is at (0,0,0))

  • a_min (double) – minimale scale factor

  • noise_std (double) – standard deviation for the Gaussian noise

  • seedphases (int) – (first) random seed to be used for the phase realizations

  • fixphases (bool) – fix the phase realization? if True the seed used will always be seedphases

  • seednoise (int) – (first) random seed to be used for the noise realizations

  • fixnoise (bool) – fix the noise realization? if True the seed used will always be seednoise

  • save_frequency (int) – saves the output on the blackbox on disk each save_frequency evaluations

Note

corner0, corner1, corner2, and a_min have no influence on the blackbox output

_aux_blackbox(P, seedphases=None, seednoise=None)[source]

Auxiliary routine for the GRF blackbox: generates a noisy realization from an input power spectrum object, and returns its normalized estimated power spectrum.

Parameters

  • P (PowerSpectrum) – input power spectrum object

  • seedphases (int, optional, default=None) – value of the seed to generate the phases of the Gaussian random field

  • seednoise (int, optional, default=None) – value of the seed to generate the noise realization, uses current state if set to None

Returns

Phi – vector of summary statistics

Return type

array, double, dimension=P

_get_powerspectrum_from_cosmo(cosmo, fname_powerspectrum, force=False)[source]

Loads or computes the power spectrum from input cosmological parameters.

Parameters

  • cosmo (dictionary) – cosmological parameters (and some infrastructure parameters)

  • fname_powerspectrum (str) – name of input/output power spectrum file

  • force (bool, optional, default=False) – force recomputation?

Returns

P – power spectrum object

Return type

PowerSpectrum

_get_powerspectrum_from_theta(theta)[source]

Returns a power spectrum from its value at support wavenumbers, by performing a Spline interpolation.

Parameters

theta (array, double, dimension=S) – vector of power spectrum values at the support wavenumbers

Returns

P – power spectrum object

Return type

PowerSpectrum

compute_pool(theta, d, pool_fname, N)[source]

Computes a pool of realizations of the GRF blackbox. A method compute_pool with this prototype is the only mandatory method.

Parameters

  • theta (array, double, dimension=S) – vector of power spectrum values at the support wavenumbers

  • d (int) – direction in parameter space, from 0 to S

  • pool_fname (str) – pool file name

  • N (int) – number of realizations required

Returns

p – simulation pool

Return type

pool

evaluate(theta, seedphases=None, seednoise=None, i=0, N=0)[source]

Evaluates the GRF blackbox from an input vector of power spectrum coefficients at the support wavenumbers.

Parameters

  • theta (array, double, dimension=S) – vector of power spectrum values at the support wavenumbers

  • seedphases (int, optional, default=None) – value of the seed to generate the phases of the Gaussian random field

  • seednoise (int, optional, default=None) – value of the seed to generate the noise realization, uses current state if set to None

  • i (int, optional, default=0) – current evaluation index of the blackbox

  • N (int, optional, default=0) – total number of evaluations of the blackbox

Returns

Phi – vector of summary statistics

Return type

array, double, dimension=P

make_data(cosmo, fname_powerspectrum, seedphases=None, seednoise=None, force=False)[source]

Evaluates the GRF blackbox to make mock data, from input cosmological parameters.

Parameters

  • cosmo (dictionary) – cosmological parameters (and some infrastructure parameters)

  • fname_powerspectrum (str) – name of input/output power spectrum file

  • seedphases (int, optional, default=None) – value of the seed to generate the phases of the Gaussian random field

  • seednoise (int, optional, default=None) – value of the seed to generate the noise realization, uses current state if set to None

  • force (bool, optional, default=False) – force recomputation?

Returns

Phi – vector of summary statistics

Return type

array, double, dimension=P