General utilities

gwmemory.utils.combine_modes(h_lm: dict, inc: float, phase: float) → ndarray

Calculate the plus and cross polarisations of the waveform from the spherical harmonic decomposition.

gwmemory.utils.load_sxs_waveform(file_name: str, modes: list = None, extraction: str = 'OutermostExtraction.dir') → Tuple[dict, ndarray]

Load the spherical harmonic modes of an SXS numerical relativity waveform.

Parameters:

file_name: str

Name of file to be loaded.

modes: dict

Dictionary of spherical harmonic modes to extract, default is all in ell<=4.

extraction: str

String representing extraction method, default is ‘OutermostExtraction.dir’

Returns:

output: dict

Dictionary of requested spherical harmonic modes.

gwmemory.utils.nfft(ht: ndarray, sampling_frequency: float) → Tuple[ndarray, ndarray]

performs an FFT while keeping track of the frequency bins assumes input time series is real (positive frequencies only)

Parameters:

ht: array-like

Time series to FFT

sampling_frequency: float

Sampling frequency of input time series

Returns:

hf: array-like

Single-sided FFT of ft normalised to units of strain / sqrt(Hz)

f: array-like

Frequencies associated with hf