#!/usr/bin/python
import os,sys
from ROOT import *

L1 = 1E-6  #metal
L2 = 30E-6 #gas
m  = 0.99

fu1 = 'exp(-1.*'+str(L1)+'*x)'
fu2 = 'exp(-1.*'+str(L2)+'*x)'
fu3 = str(m)+'*'+fu1+' + '+str(1-m)+'*'+fu2

#print fu1
#print fu2
#print fu3

gr = TGraph()
for i in range(100):
    t = 100*i
    gr.SetPoint(i,t,m*exp(-1.*L1*t)+(1-m)*exp(-1.*L2*t))

gr.SetMarkerStyle(5)

def my_exp(x,par): return par[0]*exp(-1*par[1]*x[0])
tf_exp = TF1('tf_exp', my_exp, 1000., 10000., 2 )

gr.Fit(tf_exp,'R','',1000.,10000.)

c = TCanvas()
gr.Draw('AP')
au = raw_input('>')