histogram.py

import ROOT
from ROOT import TH1F, TFile, TTree, TString, gSystem

## Class for Histograms
# initialize histograms the same way like when using TH1F only with Histograms
# the constuctor initializes 3 TH1F objects.
class Histogram(object):
	def __init__(self, outputFile, inhalt, title, nbins, minbin, maxbin):
		#print str(self) + ": __init__"
		xaxistitle = title		
		title = "CMS Private Work " + title
		self.pos = TH1F(inhalt+"pos",title+" with pos. weights",nbins,minbin,maxbin)
		self.neg = TH1F(inhalt+"neg",title+" with neg. weights",nbins,minbin,maxbin)
		self.combined = TH1F(inhalt,title,nbins,minbin,maxbin)
		ROOT.gROOT.SetBatch(True) # suppress the creation of canvases on the screen.. much much faster if over a remote connection
		ROOT.gROOT.SetStyle("Plain") #To set plain bkgds for slides
		ROOT.gStyle.SetCanvasColor(0)#Sets canvas colour white	
		ROOT.gStyle.SetStripDecimals(ROOT.kTRUE);
		ROOT.gStyle.SetLineWidth(2)			
		self.pos.GetYaxis().SetTitle("Normalized units")
                self.pos.GetXaxis().SetTitle(xaxistitle+" (pos wgts)")
		self.pos.SetLineWidth(2)
		self.neg.GetYaxis().SetTitle("Normalized units")
                self.neg.GetXaxis().SetTitle(xaxistitle+" (neg wgts)")
		self.neg.SetLineWidth(2)
		self.combined = TH1F(inhalt,title,nbins,minbin,maxbin)
		self.combined.GetYaxis().SetTitle("Normalized units")
                self.combined.GetXaxis().SetTitle(xaxistitle)
		self.combined.SetLineWidth(2)
		self.outputFile = outputFile
                
                self.pos.Sumw2()        # required here!
                self.neg.Sumw2()        # required here!
	        self.combined.Sumw2()   # required here!
        
	def check(self, caller):
		if (self.pos is None) or (self.neg is None) or (self.combined is None):
			print caller + ": Warning: histogram->check() failed. (None)"
			raise Exception("stop.")
			return False
	
		if (str(self.pos) == 'None') or (str(self.neg) == 'None') or (str(self.combined) == 'None'):
			print caller + ": Warning: histogram->check() failed. ('None')"
			raise Exception("stop.")
			return False
		return True
	
	def fill(self,weight,value):
		#print str(self) + ": fill"
		#print str(self.pos)
		#print str(self.neg)
		#print str(self.combined)
		#if not self.check("fill"):
		#	return
		
		if weight >0:
			self.pos.Fill(value,1.)
			self.combined.Fill(value,1.)
		elif weight < 0:
			self.neg.Fill(value,-1.)
			self.combined.Fill(value,-1.)
	def finalize(self):
		
		if not self.check("finalize"):
			return
		
		#print str(self) + ": finalize"
		self.outputFile.WriteTObject(self.pos)
		self.outputFile.WriteTObject(self.neg)
		self.outputFile.WriteTObject(self.combined)
        #del self
	#def __del__(self):
		#print str(self) + ": __del__"