Revision a794a6590d1184c57f65760f9e382c5c6c9bfb03 authored by Unknown Author on 31 May 2006, 07:48:57 UTC, committed by Unknown Author on 31 May 2006, 07:48:57 UTC
git-svn-id: http://root.cern.ch/svn/root/tags/v5-11-04@15252 27541ba8-7e3a-0410-8455-c3a389f83636
1 parent ca81efd
multifit.py
# To see the output of this macro, click begin_html <a href="gif/multifit.gif" >here</a> end_html
# Example showing how to fit in a sub-range of an histogram
# An histogram is created and filled with the bin contents and errors
# defined in the table below.
# 3 gaussians are fitted in sub-ranges of this histogram.
# A new function (a sum of 3 gaussians) is fitted on another subrange
# Note that when fitting simple functions, such as gaussians, the initial
# values of parameters are automatically computed by ROOT.
# In the more complicated case of the sum of 3 gaussians, the initial values
# of parameters must be given. In this particular case, the initial values
# are taken from the result of the individual fits.
from ROOT import TH1F, TF1
from ROOT import gROOT
from array import array
gROOT.Reset()
x = ( 1.913521, 1.953769, 2.347435, 2.883654, 3.493567,
4.047560, 4.337210, 4.364347, 4.563004, 5.054247,
5.194183, 5.380521, 5.303213, 5.384578, 5.563983,
5.728500, 5.685752, 5.080029, 4.251809, 3.372246,
2.207432, 1.227541, 0.8597788,0.8220503,0.8046592,
0.7684097,0.7469761,0.8019787,0.8362375,0.8744895,
0.9143721,0.9462768,0.9285364,0.8954604,0.8410891,
0.7853871,0.7100883,0.6938808,0.7363682,0.7032954,
0.6029015,0.5600163,0.7477068,1.188785, 1.938228,
2.602717, 3.472962, 4.465014, 5.177035 )
np = len(x)
h = TH1F( 'h', 'Example of several fits in subranges', np, 85, 134 )
h.SetMaximum( 7 )
for i in xrange(np):
h.SetBinContent( i+1, x[i] )
par = array( 'd', 9*[0.] )
g1 = TF1( 'g1', 'gaus', 85, 95 )
g2 = TF1( 'g2', 'gaus', 98, 108 )
g3 = TF1( 'g3', 'gaus', 110, 121 )
total = TF1( 'total', 'gaus(0)+gaus(3)+gaus(6)', 85, 125 )
total.SetLineColor( 2 )
h.Fit( g1, 'R' )
h.Fit( g2, 'R+' )
h.Fit( g3, 'R+' )
par1 = g1.GetParameters()
par2 = g2.GetParameters()
par3 = g3.GetParameters()
par[0], par[1], par[2] = par1[0], par1[1], par1[2]
par[3], par[4], par[5] = par2[0], par2[1], par2[2]
par[6], par[7], par[8] = par3[0], par3[1], par3[2]
total.SetParameters( par )
h.Fit( total, 'R+' )
![swh spinner](/static/img/swh-spinner.gif)
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