-// The class calculates the electric field and space point distortions //
-// due a Gating Grid (GG) Error voltage. It uses the exact calculation //
-// technique based on bessel functions. (original code from STAR) //
-// The class allows "effective Omega Tau" corrections. //
-// //
-// date: 27/04/2010 //
-// Authors: Jim Thomas, Stefan Rossegger, Magnus Mager //
-// //
-// Example usage: //
-// AliTPCGGVoltError GGerror; //
-// GGerror.SetOmegaTauT1T2(0.32,1.,1.); // values ideally from OCDB //
-// GGerror.SetDeltaVGGA(50.); // voltage offset A-side //
-// GGerror.SetDeltaVGGC(50.); // voltage offset C-side //
-// GGerror.InitGGVoltErrorDistortion(); // initialization of the look up //
-// // plot dRPhi distortions ... //
-// GGerror.CreateHistoDRPhiinZR(1.,100,100)->Draw("surf2"); //