#! /usr/bin/env python

import ROOT
import glob

c1 = ROOT.TCanvas('c1', 'c1', 600, 400)
chain = ROOT.TChain ('PEtree')
files = glob.glob ('PEs_seed*.root')
for rootfile in files:
    chain.AddFile (rootfile)
# pull
pullName = 'TopPull'
pull = ROOT.TH1F (pullName, pullName, 100, -5, 5)
chain.Draw ("(measVec[0]-genVec[0])/errVec[0]>>%s" % \
            (pullName))
# pull.Fit('gaus')
c1.Print ('%s.png' % pullName)
print "Done."