JGEOMETRY3D::JEigenValues3D Struct Reference

Eigen values in 3D. More...

#include <JEigen3D.hh>

Inheritance diagram for JGEOMETRY3D::JEigenValues3D:

Public Member Functions
template<class T >
	JEigenValues3D (T __begin, T __end)
	Constructor.

Detailed Description

Eigen values in 3D.

Definition at line 33 of file JEigen3D.hh.

Constructor & Destructor Documentation

JEigenValues3D()

template<class T >

JGEOMETRY3D::JEigenValues3D::JEigenValues3D ( T __begin, T __end )

inline

Constructor.

Parameters

__begin	begin of data
__end	end of data

Definition at line 43 of file JEigen3D.hh.

    {
      const JCenter3D center(__begin, __end);
        
      // RMS matrix
        
      TMatrixDSym A(3);
 
      A = 0.0;
        
      for (T i = __begin; i != __end; ++i) {
        
        const double dx = center.getX() - i->getX();
        const double dy = center.getY() - i->getY();
        const double dz = center.getZ() - i->getZ();
          
        A(0,0) += (dx * dx);
        A(0,1) += (dx * dy);
        A(0,2) += (dx * dz);
        
        A(1,1) += (dy * dy);
        A(1,2) += (dy * dz);
        
        A(2,2) += (dz * dz);
      }
      
      A(1,0) = A(0,1);
      A(2,0) = A(0,2);
      A(2,1) = A(1,2);
 
      const TMatrixDSymEigen result(A);
 
      const TVectorD& u = result.GetEigenValues();
      const TMatrixD& V = result.GetEigenVectors();
 
      for (Int_t i = 0; i != u.GetNoElements(); ++i) {
        (*this)[u[i]] = JVector3D(V(0,i),
                                  V(1,i),
                                  V(2,i));
      }
    }

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The documentation for this struct was generated from the following file:

• JEigen3D.hh