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VertexFitter.cc
Go to the documentation of this file. Or view the newest version in sPHENIX GitHub for file VertexFitter.cc
1 #include "VertexFitter.h"
2 
3 #include <HelixHough/NewtonMinimizerGradHessian.h>
4 #include <HelixHough/VertexFitFunc.h>
5 
6 // Eigen includes
7 #include <Eigen/Core>
8 
9 class SimpleTrack3D;
10 
11 using namespace std;
12 
13 //using namespace NewtonMinimizer;
14 using namespace FitNewton;
15 using namespace Eigen;
16 
18 {
19 
20 }
21 
30 bool VertexFitter::findVertex(vector<SimpleTrack3D>& tracks, vector<float>& vertex, float sigma, bool fix_xy)
31 {
32  vector<Matrix<float,5,5> > covariances;
33  return findVertex(tracks, covariances, vertex, sigma, fix_xy);
34 }
35 
36 bool VertexFitter::findVertex(vector<SimpleTrack3D>& tracks, vector<Matrix<float,5,5> >& covariances, vector<float>& vertex, float sigma, bool fix_xy)
37 {
38  VertexFitFunc _vertexfit;
39  //NewtonMinimizer::NewtonMinimizerGradHessian _minimizer;
41 
42  // setup function to minimize
43  // expo-dca2 => ~dca^2 w/ extreme outlier de-weighting
44  _vertexfit.setTracks(&tracks);
45  _vertexfit.setCovariances(&covariances);
46 
47  // setup the minimizer
48  // fast Newton gradient minimization
49  _minimizer.setFunction(&_vertexfit);
50 
51  // set an initial guess and uncertainties
52  VectorXd start_point = VectorXd::Zero(vertex.size()); // input initial guess
53  for(unsigned int i=0;i<vertex.size();++i)
54  {
55  start_point(i) = vertex[i];
56  }
57  if(fix_xy)
58  {
59  _minimizer.fixParameter(0);
60  _minimizer.fixParameter(1);
61  }
62  _vertexfit.setFixedPar(0, sigma); // index = 0 used for x,y,z uncertainties
63 
64  // output storage
65  VectorXd min_point = VectorXd::Zero(vertex.size()); // output vector for minimize method below
66 
67  // minimize
68  _minimizer.minimize(start_point, min_point, 1.0e-12, 48, 1.0e-18);
69 
70  // store output vertex spatial point
71  for(unsigned i=0; i<vertex.size(); i++)
72  {
73  vertex[i] = min_point(i);
74  }
75 
76  return true;
77 }