fit multiple parametric curves with scipy

Question

I have a set (at least 3) of curves (xy-data). For each curve the parameters E and T are constant but different. I\'m searching the coefficients a,n and m for the best fit o

Answer 1

thanks Evert for the reply.

Exactly what I needed to know!!

I have simplyfied the function as far as possible, as you suggested. However, the task was to find ONE set of A,m,n to fit all curves. So my code look like this:

import numpy
import math
from scipy.optimize import leastsq

#+++++++++++++++++++++++++++++++++++++++++++++
def fit(x,T,A,n,m):
  return A/(n+1.0)*math.pow(T,(n+1.0))*numpy.power(x,m)
#+++++++++++++++++++++++++++++++++++++++++++++
def leastsq_func(params, *args):
  cc=args[0]   #number of curves
  incs=args[1] #number of points 
  x=args[2]
  y=args[3]
  T=args[4:]

  A=params[0]
  n=params[1]
  m=params[2]

  yfit=numpy.empty(x.shape)
  for i in range(cc):
    v=i*incs
    b=(i+1)*incs
    if b

Works like clockwork.

At first I put the Ts in the params0 list and they were modified during iteration leading to nonsense results. Obvious, if you think about it. Afterwards ;-)

So, Vielen Dank! J.