transposeHistAndGraph.py

import ROOT as r
class Transpose():

    def transposeHist(self,inHist):
        outName = inHist.GetName()
        binWidthX = 2*(inHist.GetXaxis().GetBinCenter(1)-inHist.GetXaxis().GetBinLowEdge(1))
        binWidthY = 2*(inHist.GetYaxis().GetBinCenter(1)-inHist.GetYaxis().GetBinLowEdge(1))
        xMass = [inHist.GetXaxis().GetBinCenter(x) for x in range(1,inHist.GetXaxis().GetNbins()+1)]
        yMass = [inHist.GetYaxis().GetBinCenter(y) for y in range(1,inHist.GetYaxis().GetNbins()+1)]
        xLow = [inHist.GetXaxis().GetBinLowEdge(x) for x in range(1,inHist.GetXaxis().GetNbins()+1)]
        yAxisTranspose = []
        for x in xMass:
            for y in yMass:
                if x-y >= binWidthY/2.:
                    yAxisTranspose.append(x-y-binWidthY/2.)
        minY = max(0,min(yAxisTranspose))
        maxY = max(yAxisTranspose)
        xAxis = array('d',xLow)
        yValue = minY
        yAxisTranspose = []
        while yValue <= maxY+binWidthY:
            yAxisTranspose.append(yValue)
            yValue += binWidthY
        yAxisTranspose = array('d',yAxisTranspose)
        outHist = r.TH2D(outName+"_transpose","",len(xAxis)-1,xAxis,len(yAxisTranspose)-1,yAxisTranspose)
        outHist.SetDirectory(0)
        for x in range(1,outHist.GetXaxis().GetNbins()+1):
            for y in range(1,outHist.GetYaxis().GetNbins()+1):
                value = inHist.GetBinContent(x,y)
                xValue,yValue = self.getBinCenter2D(x,y,inHist)
                newMass = xValue - yValue
                outHist.Fill(xValue,newMass,value)
        outHist.SetName(outName)
        return outHist

    def transposeGraph(self,graph):
        outputGraph = graph.Clone()
        outputSize = graph.GetN()
        outputX,outputY = array('d',[0.]*outputSize),array('d',[0.]*outputSize)
        tempX,tempY = r.Double(0.),r.Double(0.)
        for i in range(outputSize):
            graph.GetPoint(i,tempX,tempY)
            outputX[i],outputY[i] = tempX,tempX-tempY
        outputGraph = r.TGraph(outputSize,outputX,outputY)
        outputGraph.SetName(graph.GetName())
        return outputGraph

    def getBinCenter2D(self,x,y,hist):
        xValue = hist.GetXaxis().GetBinCenter(x)
        yValue = hist.GetYaxis().GetBinCenter(y)
        return xValue,yValue