HitCreatorSilicon.cxx File Reference

#include "HitCreatorSilicon.h"
#include "ISF_Event/ISFParticle.h"
#include "TrkRIO_OnTrack/RIO_OnTrack.h"
#include "TrkSurfaces/Surface.h"
#include "TrkSurfaces/SurfaceBounds.h"
#include "TrkEventPrimitives/LocalParameters.h"
#include "TrkEventPrimitives/DefinedParameter.h"
#include "TrkEventPrimitives/ParamDefs.h"
#include "TrkEventPrimitives/ParticleHypothesis.h"
#include "TrkDetElementBase/TrkDetElementBase.h"
#include "TrkExUtils/LineIntersection2D.h"
#include "TrkToolInterfaces/IRIO_OnTrackCreator.h"
#include "SiClusterizationTool/ClusterMakerTool.h"
#include "InDetReadoutGeometry/SiDetectorDesign.h"
#include "ReadoutGeometryBase/SiDiodesParameters.h"
#include "InDetPrepRawData/SiWidth.h"
#include "InDetPrepRawData/PixelCluster.h"
#include "InDetRIO_OnTrack/PixelClusterOnTrack.h"
#include "InDetIdentifier/PixelID.h"
#include "InDetIdentifier/SCT_ID.h"
#include "InDetConditionsSummaryService/IInDetConditionsTool.h"
#include "InDetSimEvent/SiHit.h"
#include "GeoPrimitives/CLHEPtoEigenConverter.h"
#include "CLHEP/Units/SystemOfUnits.h"
#include "CLHEP/Random/RandFlat.h"
#include "CLHEP/Random/RandGauss.h"
#include "CLHEP/Random/RandLandau.h"
#include <TMath.h>
#include <TF1.h>
#include <vector>

Go to the source code of this file.

Functions
double	langaufun_fast (double *x, double *par)

Function Documentation

langaufun_fast()

double langaufun_fast	(	double *	x,
		double *	par )

Definition at line 114 of file HitCreatorSilicon.cxx.

                                             {
  //Fit parameters:
  //par[0]=Width (scale) parameter of Landau density
  //par[1]=Most Probable (MP, location) parameter of Landau density
  //par[2]=Total area (integral -inf to inf, normalization constant)
  //par[3]=Width (sigma) of convoluted Gaussian function
  //
  //In the Landau distribution (represented by the CERNLIB approximation),
  //the maximum is located at x=-0.22278298 with the location parameter=0.
  //This shift is corrected within this function, so that the actual
  //maximum is identical to the MP parameter.
 
  // Numeric constants
  float invsq2pi = 0.3989422804014;   // (2 pi)^(-1/2)
  float mpshift  = -0.22278298;       // Landau maximum location
  // Gauss lookup table - let's be honest, these are always the same values...
  // This table is specific to the following np value and needs adaptation in case np is changed
  double gauss_lut[50] = {0.998750780887374456,0.988813043727165275,0.96923323447634413,0.940588065326561695,0.903707082721058597,
    0.859632757966350525,0.809571661213986715,0.754839601989007347,0.696804761374882342,0.636831621583786367,
    0.576229102522380576,0.516205688098894111,0.457833361771614267,0.402021370154990454,0.349500576034800337,
    0.300817976590658676,0.256340161499255759,0.216265166829887306,0.180639843651333204,0.149381761360416171,
    0.122303465302261424,0.0991372321836489212,0.0795595087182276867,0.0632127172421080297,0.0497248676032363973,
    0.0387257750604656018,0.0298595590948963728,0.0227941808836123437,0.0172274759940137939,0.0128906873307075114,
    0.00954965878387800497,0.00700416504525899417,0.00508606923101270064,0.00365649704823364612,0.0026025848245772071,
    0.0018340111405293852,0.00127954549250140965,0.000883826306935049958,0.000604414925679283501,0.000409223053150731654,
    0.000274310255595171487,0.000182046138317709796,0.000119612883581024366,7.78093008945889215e-05,5.01120454198365631e-05,
    3.19527960443799922e-05,2.01712861314266379e-05,1.26071051770485227e-05,7.8010709105552431e-06,4.77914424437207415e-06};
  // Control constants
  float np = 100.0;      // number of convolution steps
  float sc =   5.0;      // convolution extends to +-sc Gaussian sigmas
 
  // Variables
  float xx;
  float mpc;
  float fland;
  float sum = 0.0;
  float xlow,xupp;
  float step;
  int i;
 
  // MP shift correction
  mpc = par[1] - mpshift * par[0];
 
  // Range of convolution integral
  xlow = x[0] - sc * par[3];
  xupp = x[0] + sc * par[3];
 
  step = (xupp-xlow) / np;
 
  // Convolution integral of Landau and Gaussian by sum
  for(i=0; i < np/2; i++) {
    xx = x[0] +(((float) i)-.5) * step; //x[0] - (((float) i)+.5) * step;
    fland = TMath::Landau(xx,mpc,par[0]) / par[0];
    sum += fland * gauss_lut[i];
 
    xx = x[0] -(((float) i)-.5) * step; // x[0] + (((float) i)+.5) * step;
    fland = TMath::Landau(xx,mpc,par[0]) / par[0];
    sum += fland * gauss_lut[i];
  }
 
  return (par[2] * step * sum * invsq2pi / par[3]);
}