// gROOT->SetStyle("Plain"); gStyle->SetPalette(1);
// TCanvas *c2 = new TCanvas("cAliTPCROCVoltError3D","cAliTPCROCVoltError3D",500,400);
// AliTPCROCVoltError3D roc;
+// roc.SetROCDataFileName("$ALICE_ROOT/TPC/Calib/maps/TPCROCdzSurvey.root");
// roc.SetElectronArrivalCorrection(kFALSE); // Correction for electron arrival offset, IROC vs OROC
// roc.SetROCDisplacement(kTRUE); // include the chamber offset in z when calculating the dz
// roc.SetOmegaTauT1T2(0,1,1); // B=0