Hi, ROOT experts,
I have a script to make the ROC curve out of the TMVA output file by using the cuts:
import numpy as np
import ROOT
from ROOT import TFile, TTree, TCanvas, TGraph, TPad, TLegend
f = TFile.Open("factoryOutputFile.root")
t = f.Get("dataLoader/TestTree")
nSigTot = t.Draw("PyTorch", "classID==0")
nBkgTot = t.Draw("PyTorch", "classID==1")
gr = TGraph()
cutValues = np.array([])
cut = 0
while cut <= 0.96:
cutValues = np.append(cutValues, cut)
cut += 0.01
while cut > 0.96 and cut <= 1.0:
cutValues = np.append(cutValues, cut)
cut += 0.001
for cut in cutValues:
cutSig = f"classID==0 && PyTorch > {cut}"
cutBkg = f"classID==1 && PyTorch > {cut}"
sigCount = t.GetEntries(cutSig)
bkgCount = t.GetEntries(cutBkg)
eff = sigCount / nSigTot
rej = 1 - bkgCount / nBkgTot
gr.SetPoint(gr.GetN(), eff, rej)
canvas = TCanvas("c1", "Signal efficiency vs. Background rejection", 10, 10, 850, 500)
canvas.cd()
ROOT.gStyle.SetOptStat(0)
ROOT.gPad.SetLeftMargin(0.15)
grid = TPad("grid", "", 0, 0, 1, 1)
grid.Draw()
grid.cd()
grid.SetGrid()
gr.SetTitle("Signal efficiency vs. Background rejection")
gr.GetXaxis().SetTitle("Signal efficiency (Sensitivity)")
gr.GetXaxis().SetRangeUser(0.92,1.0015)
gr.GetYaxis().SetTitle("Background rejection (Specificity)")
gr.GetYaxis().SetRangeUser(0.9,1.001)
gr.SetLineWidth(2)
gr.SetLineColor(4)
gr.Draw("AL")
leg = TLegend(0.15, 0.15, 0.35, 0.3)
leg.SetHeader("MVA Method", "")
leg.AddEntry(gr, "PyTorch_CNN", "l");
leg.Draw()
canvas.Print("cuts.pdf", "pdf")
Here is the plot:
roc.pdf (14.3 KB)
Now I am trying to find a way to get the event numbers added by loader.AddSpectator("event_number") for the false positives at a certain threshold because I want to see what background events didn’t get rejected by the classifier; for example, when the sensitivity equals 0.97 and the background rejection equals 0.9989 by looking at the ROC curve, how do I do that? I have event_number in the TestTree, hope you can give me some guidance.
Thank you!