add option to tweak curve_fit tolerance and set new default

Author: TomDonoghue

fooof/objs/fit.py

@@ -192,12 +192,16 @@ def __init__(self, peak_width_limits=(0.5, 12.0), max_n_peaks=np.inf, min_peak_h
         self._gauss_overlap_thresh = 0.75
         # Parameter bounds for center frequency when fitting gaussians, in terms of +/- std dev
         self._cf_bound = 1.5
-        # The maximum number of calls to the curve fitting function
-        self._maxfev = 5000
         # The error metric to calculate, post model fitting. See `_calc_error` for options
         #   Note: this is for checking error post fitting, not an objective function for fitting
         self._error_metric = 'MAE'
 
+        ## PRIVATE CURVE_FIT SETTINGS
+        # The maximum number of calls to the curve fitting function
+        self._maxfev = 5000
+        # The tolerance setting for curve fitting (see scipy.curve_fit - ftol / xtol / gtol)
+        self._tol = 0.00001
+
         ## RUN MODES
         # Set default debug mode - controls if an error is raised if model fitting is unsuccessful
         self._debug = False
@@ -947,6 +951,7 @@ def _simple_ap_fit(self, freqs, power_spectrum):
                 aperiodic_params, _ = curve_fit(get_ap_func(self.aperiodic_mode),
                                                 freqs, power_spectrum, p0=guess,
                                                 maxfev=self._maxfev, bounds=ap_bounds,
+                                                ftol=self._tol, xtol=self._tol, gtol=self._tol,
                                                 check_finite=False)
         except RuntimeError as excp:
             error_msg = ("Model fitting failed due to not finding parameters in "
@@ -1005,6 +1010,7 @@ def _robust_ap_fit(self, freqs, power_spectrum):
                 aperiodic_params, _ = curve_fit(get_ap_func(self.aperiodic_mode),
                                                 freqs_ignore, spectrum_ignore, p0=popt,
                                                 maxfev=self._maxfev, bounds=ap_bounds,
+                                                ftol=self._tol, xtol=self._tol, gtol=self._tol,
                                                 check_finite=False)
         except RuntimeError as excp:
             error_msg = ("Model fitting failed due to not finding "
@@ -1152,6 +1158,7 @@ def _fit_peak_guess(self, guess):
         try:
             gaussian_params, _ = curve_fit(gaussian_function, self.freqs, self._spectrum_flat,
                                            p0=guess, maxfev=self._maxfev, bounds=gaus_param_bounds,
+                                           ftol=self._tol, xtol=self._tol, gtol=self._tol,
                                            check_finite=False)
         except RuntimeError as excp:
             error_msg = ("Model fitting failed due to not finding "

fooof/tests/objs/test_fit.py

@@ -391,7 +391,7 @@ def test_fooof_fit_failure():
 
     ## Induce a runtime error, and check it runs through
     tfm = FOOOF(verbose=False)
-    tfm._maxfev = 5
+    tfm._maxfev = 2
 
     tfm.fit(*gen_power_spectrum([3, 50], [50, 2], [10, 0.5, 2, 20, 0.3, 4]))
 
@@ -417,7 +417,7 @@ def test_fooof_debug():
     """Test FOOOF in debug mode, including with fit failures."""
 
     tfm = FOOOF(verbose=False)
-    tfm._maxfev = 5
+    tfm._maxfev = 2
 
     tfm.set_debug_mode(True)
     assert tfm._debug is True