def _regenerate_model(self):
"""Regenerate model fit from parameters."""
self._ap_fit = gen_aperiodic(self.freqs, self.aperiodic_params_)
self._peak_fit = gen_peaks(self.freqs,
np.ndarray.flatten(self._gaussian_params))
self.fooofed_spectrum_ = self._peak_fit + self._ap_fit
def _robust_ap_fit(self, freqs, power_spectrum):
"""Fit the aperiodic component of the power spectrum robustly, ignoring outliers.
Parameters
----------
freqs : 1d array
Frequency values for the power spectrum, in linear scale.
power_spectrum : 1d array
Power values, in log10 scale.
Returns
-------
aperiodic_params : 1d array
Parameter estimates for aperiodic fit.
"""
# Do a quick, initial aperiodic fit
popt = self._simple_ap_fit(freqs, power_spectrum)
initial_fit = gen_aperiodic(freqs, popt)
# Flatten power_spectrum based on initial aperiodic fit
flatspec = power_spectrum - initial_fit
# Flatten outliers - any points that drop below 0
flatspec[flatspec < 0] = 0
# Use percential threshold, in terms of # of points, to extract and re-fit
perc_thresh = np.percentile(flatspec, self._ap_percentile_thresh)
perc_mask = flatspec <= perc_thresh
freqs_ignore = freqs[perc_mask]
spectrum_ignore = power_spectrum[perc_mask]
# Second aperiodic fit - using results of first fit as guess parameters
# See note in _simple_ap_fit about warnings
with warnings.catch_warnings():
warnings.simplefilter("ignore")
aperiodic_params, _ = curve_fit(get_ap_func(self.aperiodic_mode),
freqs_ignore,
spectrum_ignore,
p0=popt,
maxfev=5000,
bounds=self._ap_bounds)
return aperiodic_params
def fit(self, freqs=None, power_spectrum=None, freq_range=None):
"""Fit the full power spectrum as a combination of periodic and aperiodic components.
Parameters
----------
freqs : 1d array, optional
Frequency values for the power spectrum, in linear space.
power_spectrum : 1d array, optional
Power values, which must be input in linear space.
freq_range : list of [float, float], optional
Frequency range to restrict power spectrum to. If not provided, keeps the entire range.
Notes
-----
Data is optional if data has been already been added to FOOOF object.
"""
# If freqs & power_spectrum provided together, add data to object.
if freqs is not None and power_spectrum is not None:
self.add_data(freqs, power_spectrum, freq_range)
# If power spectrum provided alone, add to object, and use existing frequency data
# Note: be careful passing in power_spectrum data like this:
# It assumes the power_spectrum is already logged, with correct freq_range.
elif isinstance(power_spectrum, np.ndarray):
self.power_spectrum = power_spectrum
# Check that data is available
if self.freqs is None or self.power_spectrum is None:
raise ValueError('No data available to fit - can not proceed.')
# Check and warn about width limits (if in verbose mode)
if self.verbose:
self._check_width_limits()
# In rare cases, the model fails to fit. Therefore it's in a try/except
# Cause of failure: RuntimeError, failure to find parameters in curve_fit
try:
# Fit the aperiodic component
self.aperiodic_params_ = self._robust_ap_fit(
self.freqs, self.power_spectrum)
self._ap_fit = gen_aperiodic(self.freqs, self.aperiodic_params_)
# Flatten the power_spectrum using fit aperiodic fit
self._spectrum_flat = self.power_spectrum - self._ap_fit
# Find peaks, and fit them with gaussians
self._gaussian_params = self._fit_peaks(
np.copy(self._spectrum_flat))
# Calculate the peak fit
# Note: if no peaks are found, this creates a flat (all zero) peak fit.
self._peak_fit = gen_peaks(
self.freqs, np.ndarray.flatten(self._gaussian_params))
# Create peak-removed (but not flattened) power spectrum.
self._spectrum_peak_rm = self.power_spectrum - self._peak_fit
# Run final aperiodic fit on peak-removed power spectrum
# Note: This overwrites previous aperiodic fit
self.aperiodic_params_ = self._simple_ap_fit(
self.freqs, self._spectrum_peak_rm)
self._ap_fit = gen_aperiodic(self.freqs, self.aperiodic_params_)
# Create full power_spectrum model fit
self.fooofed_spectrum_ = self._peak_fit + self._ap_fit
# Convert gaussian definitions to peak parameters
self.peak_params_ = self._create_peak_params(self._gaussian_params)
# Calculate R^2 and error of the model fit.
self._calc_r_squared()
self._calc_rmse_error()
# Catch failure, stemming from curve_fit process
except RuntimeError:
# Clear any interim model results that may have run
# Partial model results shouldn't be interpreted in light of overall failure
self._reset_data_results(clear_freqs=False,
clear_spectrum=False,
clear_results=True)
# Print out status
if self.verbose:
print('Model fitting was unsuccessful.')
###################################################################################################
#
# The FOOOF object stores most of the intermediate steps internally.
#
# For this notebook, we will first fit the full model, as normal, but then step through,
# and visualize each step the algorithm takes to come to that final fit.
#
# Fit the FOOOF model
fm.fit(freqs, spectrum, [3, 40])
###################################################################################################
# Do an initial aperiodic signal fit - a robust fit, that excludes outliers
# This recreates an initial fit that isn't ultimately stored in the FOOOF object)
init_ap_fit = gen_aperiodic(fm.freqs,
fm._robust_ap_fit(fm.freqs, fm.power_spectrum))
# Plot the initial aperiodic fit
_, ax = plt.subplots(figsize=(12, 10))
plot_spectrum(fm.freqs,
fm.power_spectrum,
plt_log,
label='Original Power Spectrum',
ax=ax)
plot_spectrum(fm.freqs,
init_ap_fit,
plt_log,
label='Initial Aperiodic Fit',
ax=ax)
###################################################################################################
