peak fitting #68
156
pyzebra/fit2.py
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156
pyzebra/fit2.py
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import numpy as np
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from lmfit import Model, Parameters
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from scipy import integrate
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from scipy.integrate import simps
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def find_nearest(array, value):
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array = np.asarray(array)
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idx = (np.abs(array - value)).argmin()
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return idx
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def fitccl(
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data, keys, guess, vary, constraints_min, constraints_max, numfit_min=None, numfit_max=None
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):
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"""Made for fitting of ccl date where 1 peak is expected. Allows for combination of gaussian, lorentzian and linear model combination
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:param data: dictionary after peak fining
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:param keys: name of the measurement in the data dict (i.e. M123)
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:param guess: initial guess for the fitting, if none, some values are added automatically in order (see below)
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:param vary: True if parameter can vary during fitting, False if it to be fixed
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:param numfit_min: minimal value on x axis for numerical integration - if none is centre of gaussian minus 3 sigma
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:param numfit_max: maximal value on x axis for numerical integration - if none is centre of gaussian plus 3 sigma
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:param constraints_min: min constranits value for fit
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:param constraints_max: max constranits value for fit
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:return data dict with additional values
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order for guess, vary, constraints_min, constraints_max
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[Gaussian centre, Gaussian sigma, Gaussian amplitude, Lorentzian centre, Lorentzian sigma, Lorentzian amplitude, background slope, background intercept]
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examples:
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guess = [None, None, 100, None, None, None, 0, None]
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vary = [True, True, True, True, False, True, True, True]
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constraints_min = [23, None, 50, None, None, None, 0, 0]
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constraints_min = [80, None, 1000, None, None, None, 0, 100]
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"""
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if len(data["Measurements"][str(keys)]["peak_indexes"]) != 1:
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print("NO PEAK or more than 1 peak")
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return
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x = list(data["Measurements"][str(keys)]["omega"])
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y = list(data["Measurements"][str(keys)]["counts"])
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peak_index = data["Measurements"][str(keys)]["peak_indexes"]
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peak_height = data["Measurements"][str(keys)]["peak_heights"]
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print("before", constraints_min)
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guess[0] = x[int(peak_index)] if guess[0] is None else guess[0]
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guess[1] = 0.1 if guess[1] is None else guess[1]
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guess[2] = float(peak_height / 10) if guess[2] is None else float(guess[2])
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guess[3] = x[int(peak_index)] if guess[3] is None else guess[3]
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guess[4] = 2 * guess[1] if guess[4] is None else guess[4]
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guess[5] = float(peak_height / 10) if guess[5] is None else float(guess[5])
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guess[6] = 0 if guess[6] is None else guess[6]
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guess[7] = np.median(x) if guess[7] is None else guess[7]
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constraints_min[0] = np.min(x) if constraints_min[0] is None else constraints_min[0]
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constraints_min[3] = np.min(x) if constraints_min[3] is None else constraints_min[3]
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constraints_max[0] = np.max(x) if constraints_max[0] is None else constraints_max[0]
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constraints_max[3] = np.max(x) if constraints_max[3] is None else constraints_max[3]
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print("key", keys)
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print("after", constraints_min)
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def find_nearest(array, value):
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array = np.asarray(array)
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idx = (np.abs(array - value)).argmin()
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return idx
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def gaussian(x, g_cen, g_width, g_amp):
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"""1-d gaussian: gaussian(x, amp, cen, wid)"""
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return (g_amp / (np.sqrt(2.0 * np.pi) * g_width)) * np.exp(
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-((x - g_cen) ** 2) / (2 * g_width ** 2)
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)
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def lorentzian(x, l_cen, l_width, l_amp):
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"""1d lorentzian"""
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return (l_amp / (1 + ((1 * x - l_cen) / l_width) ** 2)) / (np.pi * l_width)
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def background(x, slope, intercept):
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"""background"""
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return slope * x + intercept
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mod = Model(gaussian) + Model(lorentzian) + Model(background)
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params = Parameters()
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params.add_many(
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("g_cen", x[int(peak_index)], bool(vary[0]), np.min(x), np.max(x), None, None),
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("g_width", guess[1], bool(vary[1]), constraints_min[1], constraints_max[1], None, None),
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("g_amp", guess[2], bool(vary[2]), constraints_min[2], constraints_max[2], None, None),
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("l_cen", guess[3], bool(vary[3]), np.min(x), np.max(x), None, None),
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("l_width", guess[4], bool(vary[4]), constraints_min[4], constraints_max[4], None, None),
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("l_amp", guess[5], bool(vary[5]), constraints_min[5], constraints_max[5], None, None),
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("slope", guess[6], bool(vary[6]), constraints_min[6], constraints_max[6], None, None),
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("intercept", guess[7], bool(vary[7]), constraints_min[7], constraints_max[7], None, None),
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)
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result = mod.fit(y, params, x=x)
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print("Chi-sqr: ", result.chisqr)
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comps = result.eval_components()
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gauss_3sigmamin = find_nearest(
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x, result.params["g_cen"].value - 3 * result.params["g_width"].value
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)
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gauss_3sigmamax = find_nearest(
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x, result.params["g_cen"].value + 3 * result.params["g_width"].value
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)
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numfit_min = gauss_3sigmamin if numfit_min is None else find_nearest(x, numfit_min)
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numfit_max = gauss_3sigmamax if numfit_max is None else find_nearest(x, numfit_max)
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it = -1
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while numfit_max == numfit_min:
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it = it + 1
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numfit_min = find_nearest(
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x, result.params["g_cen"].value - 3 * (1 + it / 10) * result.params["g_width"].value
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)
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numfit_max = find_nearest(
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x, result.params["g_cen"].value + 3 * (1 + it / 10) * result.params["g_width"].value
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)
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if x[numfit_min] < np.min(x):
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numfit_min = gauss_3sigmamin
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print("Minimal integration value outside of x range")
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elif x[numfit_min] >= x[numfit_max]:
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numfit_min = gauss_3sigmamin
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print("Minimal integration value higher than maximal")
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else:
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pass
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if x[numfit_max] > np.max(x):
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numfit_max = gauss_3sigmamax
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print("Maximal integration value outside of x range")
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elif x[numfit_max] <= x[numfit_min]:
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numfit_max = gauss_3sigmamax
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print("Maximal integration value lower than minimal")
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else:
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pass
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print(result.params["g_width"].value)
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print(result.params["g_cen"].value)
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num_int_area = simps(y[numfit_min:numfit_max], x[numfit_min:numfit_max])
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num_int_bacground = integrate.quad(
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background,
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x[numfit_min],
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x[numfit_max],
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args=(result.params["slope"].value, result.params["intercept"].value),
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)
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d = {}
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for pars in result.params:
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d[str(pars)] = (result.params[str(pars)].value, result.params[str(pars)].vary)
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d["export_fit"] = False
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d["int_area"] = num_int_area
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d["int_background"] = num_int_bacground
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d["full_report"] = result.fit_report()
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data["Measurements"][str(keys)]["fit"] = d
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return data
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