My tools of the trade for python programming.
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#
# wpylib.math.fitting.funcs_physics module
# Created: 20150521
# Wirawan Purwanto
#
# Imported 20150521 from Cr2_analysis_cbs.py
# (dated 20141017, CVS rev 1.143).
#
"""
wpylib.math.fitting.funcs_physics module
A library of simple f(x) functions for physics-related common functional fitting
For use with OO-style x-y curve fitting interface.
"""
import numpy
class FermiDirac_fit_func(fit_func_base):
"""Fermi-Dirac function object.
For use with fit_func function.
Functional form:
C[0] * (exp((x - C[1]) / C[2]) + 1)^-1
Coefficients:
* C[0] = amplitude
* C[1] = transition "temperature"
* C[2] = "smearing temperature"
"""
dim = 1 # a function with 1-D domain
param_names = ('A', 'F', 'T')
# FIXME: Not good yet!!!
F_guess = 1.9
T_guess = 0.05
def __call__(self, C, x):
from numpy import exp
A, F, T = self.get_params(C, *(self.param_names))
y = A * (exp((x[0] - F) / T) + 1)**(-1)
self.func_call_hook(C, x, y)
return y
def Guess_xy(self, x, y):
imin = numpy.argmin(y)
self.guess_params = (y[imin], self.F_guess, self.T_guess)
return self.guess_params