leveberg_marquardt algorithm

[Leona]

I created leveberg_marquardt algorithm and I would like to know the parameters of the function => a,b,c,d

It is working until the row: 

# do fit, here with leastsq model

minner = Minimizer(fcn2min, params, fcn_args=(x, data))

Here it stops with the sentence: TypeError: 'Parameter' object is not callable

result = minner.minimize()

Please can someone help me with this? :-)

My code:

import numpy as np

import pandas as pd

from lmfit import Minimizer, Parameters, report_fit

# intialise data of lists. 

dt = {'t':[15, 45, 75,105,135,165,195,225,255,285,315,345,375,405], 'my_test':[66,83,87,90,92,91,90,88,85,81,78,76,75,71]} 

# Create DataFrame 

df = pd.DataFrame(dt) 

df["my_kg1"] = df["my_test"]-50

df["my_kg2"] = df["my_test"]-30

#df1 = df[["my_test", "t"]]

df1 = df[["my_kg1", "t"]]

#df1 = df[["my_kg2", "t"]]

  

# Print the output. 

#print(df1)

#creating array

dat = df1.values

#print(dat)

x = dat[:, 1]

data = dat[:, 0] 

print(x)

print("--------")

print(data)

print("--------")

def fcn2min(params, x, data):

    a = params['a']

    b = params['b']

    c = params['c']

    d = params['d']

    e = params['e']

    f = params['f']

    g = params['g']

  

    model = a*e(-d*x)*(f - e((c - x)/b)/g)

    #'float' object is not callable: a*2.718(-d*x)*(1 - 2.718((c - x)/b)/2)

    return model - data

# set parameters incluing bounds

params = Parameters()

params.add('a', value=21.2, min=1.0, max=75.0)

params.add('b', value=17.9, min=0.0, max=60.0)

params.add('c', value=3.4, min=-5.0, max=6.0)

params.add('d', value=0.00, min=0.00, max=0.01)

params.add('e', value=2.718, vary=False)

params.add('f', value=1, vary=False)

params.add('g', value=2, vary=False)

# do fit, here with leastsq model

minner = Minimizer(fcn2min, params, fcn_args=(x, data))

result = minner.minimize()

# calculate final result

final = data + result.residual

# write error report

report_fit(result)

# try to plot results

try:

    import matplotlib.pyplot as plt

    plt.plot(x, data, 'k+')

    plt.plot(x, final, 'r')

    plt.show()

except ImportError:

    pass

<end of examples/doc_parameters_basic.py>

[Matt Newville]

On Tue, May 5, 2020 at 9:48 AM Leona <lenka.kr...@gmail.com> wrote:

I created leveberg_marquardt algorithm and I would like to know the parameters of the function => a,b,c,d

It is working until the row: 

# do fit, here with leastsq model

minner = Minimizer(fcn2min, params, fcn_args=(x, data))

Here it stops with the sentence: TypeError: 'Parameter' object is not callable

It's always good to include and read the error messages.  In fact, it will stop with the two lines of 

      File "<f.py>", line 43, in fcn2min

        model = a*e(-d*x)*(f - e((c - x)/b)/g)

    TypeError: 'Parameter' object is not callable

The Parameter 'e' is not a callable function, but your expression has `e` being a used as a function: `e(thing)`.  

Perhaps you meant

    model = a*e*(-d*x)*(f - e*((c - x)/b)/g)

 

Or perhaps you meant for `e` to be Euler's number and to use exponentiation, and not have `e` ~= 2.718 not be a parameter all, and use

    model = a*np.exp(-d*x)*(f - np.exp((c - x)/b)/g)

--Matt

result = minner.minimize()

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[Leona]

Thanks a lot!!! It is working :-)