#!/usr/bin/env python
# -*- coding: utf-8 -*-
"""
This code is the property of L. Bugnet (please see and cite Bugnet et al.,2018).
The user should use the FliPer method to calculate FliPer values
from 0.2 ,0.7, 7, 20 and 50 muHz.
.. codeauthor:: Lisa Bugnet <lisa.bugnet@cea.fr>
.. codeauthor:: Rasmus Handberg <rasmush@phys.au.dk>
"""
import numpy as np
# def _APODIZATION(star_tab_psd):
# """
# Function that corrects the spectra from apodization
# """
# freq = star_tab_psd[0]
# nq = np.max(freq)
# nu = np.sinc(2.*freq/nq)
# star_tab_psd[1] /= nu**2
# return star_tab_psd
def _region(star_tab_psd, inic, end):
"""
Function that calculates the average power in a given frequency range on PSD
"""
freq = star_tab_psd[0] # frequencies in muHz
power = star_tab_psd[1] # Power density in ppm2/muHz
return np.mean(power[(freq >= inic) & (freq <= end)])
[docs]
def FliPer(psd):
"""
Compute FliPer values from 0.7, 7, 20, & 50 muHz
Parameters:
psd (`powerspectrum` object): Power spectrum of which to calculate
the FliPer metrics.
Returns:
dict: Features from FliPer method.
"""
# Calculate powerspectrum with custom treatment of nans for FliPer method:
star_tab_psd = psd.standard
#star_tab_psd = _APODIZATION(star_tab_psd)
end = 277 # muHz
# Function that computes photon noise from last 100 bins of the spectra
noise = np.median(star_tab_psd[1][-100:])/((1-2./18.)**3)
return {
'Fp07': _region(star_tab_psd, 0.7, end) - noise,
'Fp7': _region(star_tab_psd, 7, end) - noise,
'Fp20': _region(star_tab_psd, 20, end) - noise,
'Fp50': _region(star_tab_psd, 50, end) - noise,
'FpWhite': noise,
'Fphi': _region(star_tab_psd, 0, 28) - noise,
'Fplo': _region(star_tab_psd, 250, end) - noise
}