def fit_three_peaks(peak_data,
pv_1_cent=3.43,
pv_1_min=3.36,
pv_1_max=3.44,
pv_2_cent=3.52,
pv_2_min=3.42,
pv_2_max=3.55,
pv_3_cent=3.59,
pv_3_min=3.54,
pv_3_max=3.6,
initParams=None):
""" Pseudo-Voigt fit to the lattice plane peak intensity for three peaks (adjust function to include more).
Parameters for each peak also require limits and centres to be set in the case of overlapping peaks.
Return results of the fit as an lmfit class, which contains the fitted parameters (amplitude, fwhm, etc.)
and the fit line calculated using the fit parameters and 100x two-theta points.
"""
ttheta = peak_data[:, 0]
intensity = peak_data[:, 1]
PV_1 = PseudoVoigtModel(prefix='pv_1')
PV_2 = PseudoVoigtModel(prefix='pv_2')
PV_3 = PseudoVoigtModel(prefix='pv_3')
model = PV_1 + PV_2 + PV_3 + Model(line)
if initParams is None:
# if reflection == '(0002),(110),(10-11)': use starting centres 3.43(min=3.36,max=3.44), 3.54(min=3.42,max=3.55), 3.59(min=3.54,max=3.6)...
#if reflection == '(20-20),(11-22),(20-21)': use starting centres 6.32(min=6.23,max=6.33), 6.45(min=6.37,max=6.47), 6.54(min=6.46,max=6.56)...
pars_1 = PV_1.guess(intensity, x=ttheta)
#note, min and max values are not the same as bounds around the peak, but values that they can go up to!
pars_1['pv_1center'].set(pv_1_cent, min=pv_1_min, max=pv_1_max)
#pars_1['pv_1sigma'].set(min=0.001, max=0.1)
#pars_1['pv_1amplitude'].set(min=0)
#pars_1['pv_1height'].set(min=10)
#pars_1['pv_1fwhm'].set(min=0.02, max=0.2)
pars_2 = PV_2.guess(intensity, x=ttheta)
pars_2['pv_2center'].set(pv_2_cent, min=pv_2_min, max=pv_2_max)
#pars_2['pv_2sigma'].set(min=0.001, max=0.1)
#pars_2['pv_2amplitude'].set(min=0)
#pars_2['pv_2height'].set(min=10, max = 5000)
#pars_2['pv_2fwhm'].set(min=0.02, max=0.2)
pars_3 = PV_3.guess(intensity, x=ttheta)
pars_3['pv_3center'].set(pv_3_cent, min=pv_3_min, max=pv_3_max)
#pars_3['pv_3sigma'].set(min=0.001, max=0.1)
#pars_3['pv_3amplitude'].set(min=1)
#pars_3['pv_3height'].set(min=10)
#pars_3['pv_3fwhm'].set(min=0.02, max=0.2)
pars = pars_1 + pars_2 + pars_3
pars.add("constBG", 0)
else:
pars = initParams
fit_results = model.fit(intensity, pars, x=ttheta)
fit_ttheta = np.linspace(ttheta[0], ttheta[-1], 100)
fit_line = [fit_ttheta, model.eval(fit_results.params, x=fit_ttheta)]
return fit_results, fit_line
def fit_one_Psudo_Voigt(x_lst,y_lst):
'''
Fits one Pseudo Voigt returns the
results object
'''
mod = PseudoVoigtModel(independent_vars=['x'],nan_policy='raise')
x_lst = np.asarray(x_lst)
y_lst = np.asarray(y_lst)
# Guess good values computer
mod.guess(y_lst,x = x_lst)
result = mod.fit(y_lst, x = x_lst)
return result
def guess_params(self, peak):
"""Guesses parameters for a new peak and adds it. See add_peak()."""
if peak.region is not self._region:
logger.error("peak with ID {} does not belong to region ID {}"
"".format(peak.ID, self._region.ID))
raise ValueError("Peak does not belong to Region")
if peak.model_name == "PseudoVoigt":
model = PseudoVoigtModel(prefix=peak.prefix)
# model.set_param_hint("fraction", vary=False)
else:
raise NotImplementedError("Only PseudoVoigt models supported")
other_models_cps = [0] * len(self._region.energy)
for other_peak in self._region.peaks:
if other_peak == peak:
continue
other_models_cps += self.get_peak_cps(other_peak, peak.energy)
y = self._region.cps - self._region.background - other_models_cps
params = model.guess(y, x=peak.energy)
self._params += params
fwhmname = "{}fwhm".format(peak.prefix)
sigmaname = "{}sigma".format(peak.prefix)
ampname = "{}amplitude".format(peak.prefix)
centername = "{}center".format(peak.prefix)
params[fwhmname].set(value=params[fwhmname].value, vary=True, min=0)
params[sigmaname].set(expr="{}/2".format(fwhmname))
params[ampname].set(min=0)
params[centername].set(min=0)
self._single_models[peak.prefix] = model
def calc_center_pseudoVoigt(vx,vy):
mod = PseudoVoigtModel()
y = vy
pars = mod.guess(y, x=vx)
out = mod.fit(y, pars, x=vx)
center = out.best_values['center']
return center
def voigt(x, y):
# Voigt fit to a curve
x_shifted = x - x.min() # Shifting to 0
y_shifted = y - y.min() # Shifting to 0
mod = PseudoVoigtModel() # Setting model type
pars = mod.guess(y_shifted, x=x_shifted) # Estimating fit
out = mod.fit(y_shifted, pars, x=x_shifted) # Fitting fit
# print(out.fit_report(min_correl=0.25)) # Outputting best fit results
print("Voigt FWHM = ", out.params['fwhm'].value) # Outputting only FWHM
out.plot() # Plotting fit
def center_psi(file_name):
#print(file_name)
psi, vx, vy = read_file(file_name)
vy = processing_of_data(psi,vx,vy)
legenda = file_name.split('/')[-1]
#plt.grid()
#plt.legend(loc=0)
#import pdb; pdb.set_trace()
plt.plot(vx,vy,label=legenda)
mod = PseudoVoigtModel()
y=vy
pars = mod.guess(y, x=vx)
out = mod.fit(y, pars, x=vx)
center =out.best_values['center']
print('center: {} <--> psi: {}'.format(center,psi))
return psi, center
def test_figure_title_using_title_keyword_argument(peakdata):
"""Test setting figure title using title keyword argument."""
x, y = peakdata
pvmodel = PseudoVoigtModel()
params = pvmodel.guess(y, x=x)
result = pvmodel.fit(y, params, x=x)
ax = result.plot_fit(title='test')
assert ax.axes.get_title() == 'test'
ax = result.plot_residuals(title='test')
assert ax.axes.get_title() == 'test'
fig, _ = result.plot(title='test')
assert fig.axes[0].get_title() == 'test'
assert fig.axes[1].get_title() == '' # no title for fit subplot
def test_figure_default_title(peakdata):
"""Test default figure title."""
x, y = peakdata
pvmodel = PseudoVoigtModel()
params = pvmodel.guess(y, x=x)
result = pvmodel.fit(y, params, x=x)
ax = result.plot_fit()
assert ax.axes.get_title() == 'Model(pvoigt)'
ax = result.plot_residuals()
assert ax.axes.get_title() == 'Model(pvoigt)'
fig, _ = result.plot()
assert fig.axes[0].get_title() == 'Model(pvoigt)' # default model.name
assert fig.axes[1].get_title() == '' # no title for fit subplot
def test_priority_setting_figure_title(peakdata):
"""Test for setting figure title: title keyword argument has priority."""
x, y = peakdata
pvmodel = PseudoVoigtModel()
params = pvmodel.guess(y, x=x)
result = pvmodel.fit(y, params, x=x)
ax = result.plot_fit(ax_kws={'title': 'ax_kws'}, title='test')
assert ax.axes.get_title() == 'test'
ax = result.plot_residuals(ax_kws={'title': 'ax_kws'}, title='test')
assert ax.axes.get_title() == 'test'
fig, _ = result.plot(ax_res_kws={'title': 'ax_res_kws'}, title='test')
assert fig.axes[0].get_title() == 'test'
assert fig.axes[1].get_title() == ''
fig, _ = result.plot(ax_fit_kws={'title': 'ax_fit_kws'}, title='test')
assert fig.axes[0].get_title() == 'test'
assert fig.axes[1].get_title() == ''
def test_figure_title_using_title_to_ax_kws(peakdata):
"""Test setting figure title by supplying ax_{fit,res}_kws."""
x, y = peakdata
pvmodel = PseudoVoigtModel()
params = pvmodel.guess(y, x=x)
result = pvmodel.fit(y, params, x=x)
ax = result.plot_fit(ax_kws={'title': 'ax_kws'})
assert ax.axes.get_title() == 'ax_kws'
ax = result.plot_residuals(ax_kws={'title': 'ax_kws'})
assert ax.axes.get_title() == 'ax_kws'
fig, _ = result.plot(ax_res_kws={'title': 'ax_res_kws'})
assert fig.axes[0].get_title() == 'ax_res_kws'
assert fig.axes[1].get_title() == ''
fig, _ = result.plot(ax_fit_kws={'title': 'ax_fit_kws'})
assert fig.axes[0].get_title() == 'Model(pvoigt)' # default model.name
assert fig.axes[1].get_title() == '' # no title for fit subplot
def fit_peak(peak_data, initParams=None):
""" Pseudo-Voigt fit to the lattice plane peak intensity.
Return results of the fit as an lmfit class, which contains the fitted parameters (amplitude, fwhm, etc.)
and the fit line calculated using the fit parameters and 100x two-theta points.
"""
ttheta = peak_data[:, 0]
intensity = peak_data[:, 1]
pvModel = PseudoVoigtModel()
model = pvModel + Model(line)
if initParams is None:
pars = pvModel.guess(intensity, x=ttheta)
pars['sigma'].set(min=0.01, max=1) #sigma is the width?
pars['amplitude'].set(min=0.05)
pars.add("constBG", 0)
else:
pars = initParams
fit_results = model.fit(intensity, pars, x=ttheta)
fit_ttheta = np.linspace(ttheta[0], ttheta[-1], 100)
fit_line = [fit_ttheta, model.eval(fit_results.params, x=fit_ttheta)]
return fit_results, fit_line
def fit_voigt(xp: XPS_experiment,
region: str,
prefix: str = 'v_',
pars: list = None,
bounds: list = None,
ax=None,
flag_plot: bool = True):
"""General method for fitting voigt model
Input
----------
xp : class XPS_experiment
XPS data
region : str
core level name
pars, bounds : list
initial guess of the fit parameters and bounds. If unspecified, guessed automatically
Returns
-----------
fitv : lmfit.model
fit result to Voigt model
"""
from lmfit.models import PseudoVoigtModel, GaussianModel
x = xp.dfx[region].dropna().energy
y = xp.dfx[region].dropna().counts
mod = PseudoVoigtModel(prefix=prefix)
if pars == None:
pars = mod.guess(y, x=x)
pars[prefix + 'sigma'].set(value=1) # Usually guessed wrong anyway
pars[prefix + 'fraction'].set(value=0.2, min=0.15, max=0.20)
fitv = mod.fit(y, pars, x=x)
xp.fit.update({region: fitv})
if flag_plot:
hatchplot_fit(xp, region, fitv, ax=ax, plot_comps=True)
return fitv
def fittingPseudoVoigt(x, y): #fits a pseudovoigt curve
mod = PseudoVoigtModel()
pars = mod.guess(y, x=x)
out = mod.fit(y, pars, x=x)
print(out.fit_report(min_correl=0.25))
return out.best_fit
'grey': '#7F7F7F',
'lightgrey': '#BFBFBF'
}
# get point-spread function data
psf = pu.load_muv_point_spread_function()
# set model x and y variables
detector_pixels = np.arange(len(psf))
detector_pixel_edges = np.linspace(0, len(psf) - 1, len(psf) + 1)
# initialize model
model = PseudoVoigtModel()
# use model's built-in initial parameters guessing option
initial_parameters = model.guess(psf, x=detector_pixels)
# fit the model to the point-spread function data
result = model.fit(psf, initial_parameters, x=detector_pixels)
params = result.params
parnames = sorted(params)
# make a figure and axes
fig, axes = plt.subplots(2,
1,
figsize=(5, 4),
sharex=True,
gridspec_kw={'height_ratios': [4, 1]},
constrained_layout=True)
# plot the IUVS data
def fit_double_shouldered_voigt(xp: XPS_experiment,
region: str,
par_g1: list,
bound_g1: list,
par_g2: list,
bound_g2: list,
lb: str = None,
ax=None,
flag_plot: bool = True) -> tuple:
x = xp.dfx[region].dropna().energy
y = xp.dfx[region].dropna().counts
### Separate two peaks ###
sepPt = find_separation_point(x, y)
x1 = x[x < sepPt].values
x2 = x[x > sepPt].values
y1 = y[x < sepPt].values
y2 = y[x > sepPt].values
### Set and guess main (voigt) components ####
vo1 = PseudoVoigtModel(prefix='v1_')
pars1 = vo1.guess(y1, x=x1)
vo2 = PseudoVoigtModel(prefix='v2_')
pars2 = vo2.guess(y2, x=x2)
pars1['v1_sigma'].set(value=1) # Usually guessed wrong anyway
pars1['v1_fraction'].set(value=0.15, min=0.15, max=0.2)
pars2['v2_sigma'].set(value=1) # Usually guessed wrong anyway
pars2['v2_fraction'].set(value=0.15, min=0.15, max=0.2)
### Set gaussian shoulders ###
gauss1 = GaussianModel(prefix='g1_')
pars1.update(gauss1.make_params())
gauss2 = GaussianModel(prefix='g2_')
pars2.update(gauss2.make_params())
mod1 = vo1 + gauss1
mod2 = vo2 + gauss2
for k, p, b in zip(gauss1.param_names, par_g1, bounds_g1):
pars1[k].set(value=p, min=b[0], max=b[1])
for k, p, b in zip(gauss2.param_names, par_g2, bounds_g2):
pars2[k].set(value=p, min=b[0], max=b[1])
fitvg1 = mod1.fit(y1, pars1, x=x1)
fitvg2 = mod2.fit(y2, pars2, x=x2)
if ax == None: ax = plt.gca()
col = plot_region(xp, region, lb, ax).get_color()
comps1 = fitvg1.eval_components(x=x1)
ax.plot(x1,
fitvg1.best_fit,
'-r',
label='best fit, $\chi^2_N$ = %i' % fitvg1.redchi)
for compo in comps1:
colc = ax.plot(
x1,
comps1[compo],
ls='dashdot',
label='%scenter: %.2f' %
(compo, fitvg1.best_values[compo + 'center']))[0].get_color()
ax.fill_between(x1, y1=0, y2=comps1[compo], alpha=0.3, color=colc)
comps2 = fitvg2.eval_components(x=x2)
ax.plot(x2,
fitvg2.best_fit,
'-',
label='best fit, $\chi^2_N$ = %i' % fitvg2.redchi)
for compo in comps2:
colc = ax.plot(
x2,
comps2[compo],
ls='dashdot',
label='%scenter: %.2f' %
(compo, fitvg2.best_values[compo + 'center']))[0].get_color()
ax.fill_between(x2, y1=0, y2=comps2[compo], alpha=0.3, color=colc)
ax.legend()
return fitvg1, fitvg2
def fit_double_voigt(xp: XPS_experiment,
region: str,
pars: list = None,
bounds: list = None,
sepPt: float = None,
frac: float = None,
lb: str = None,
ax=None,
flag_plot: bool = True,
plot_comps: bool = False,
DEBUG: bool = False):
"""Fitting double voigt model
Input
----------
xp : class XPS_experiment
XPS data
region : str
core level name
pars, bounds : list
initial guess of the fit parameters and bounds. If unspecified, guessed automatically
sepPt : float
separation point in energy between the two peaks. If unspecified guessed automatically
flag_plot, DEBUG : bool
flags to plot intermediate and final fit results
Returns
-----------
fitv : lmfit.model
fit result to Voigt model
"""
from lmfit.models import PseudoVoigtModel
x = xp.dfx[region].dropna().energy
y = xp.dfx[region].dropna().counts
if sepPt == None: sepPt = find_separation_point(x, y)
x1 = x[x < sepPt].values
x2 = x[x > sepPt].values
y1 = y[x < sepPt].values
y2 = y[x > sepPt].values
mod1 = PseudoVoigtModel(prefix='v1_')
mod2 = PseudoVoigtModel(prefix='v2_')
if pars == None:
pars1 = mod1.guess(y1, x=x1)
pars1['v1_sigma'].set(value=1) # Usually guessed wrong anyway
pars2 = mod2.guess(y2, x=x2)
pars2['v2_sigma'].set(value=1) # Usually guessed wrong anyway
if frac != None:
pars1['v1_fraction'].set(value=frac, vary=False)
pars2['v2_fraction'].set(value=frac, vary=False)
mod = mod1 + mod2
pars = mod.make_params()
pars.update(pars1)
pars.update(pars2)
if DEBUG: # Fit & plot individual components separately
fit1 = mod1.fit(y1, x=x1, params=pars1)
fit2 = mod2.fit(y2, x=x2, params=pars2)
plot_fit_result(xp, region, fit1)
plot_fit_result(xp, region, fit2)
fitv = mod.fit(y, pars, x=x)
xp.fit.update({region: fitv})
if flag_plot:
hatchplot_fit(xp, region, fitv, ax=ax, plot_comps=True)
return fitv
