UncertainSZLine.h

/**************************************************************************
 * basf2 (Belle II Analysis Software Framework)                           *
 * Author: The Belle II Collaboration                                     *
 *                                                                        *
 * See git log for contributors and copyright holders.                    *
 * This file is licensed under LGPL-3.0, see LICENSE.md.                  *
 **************************************************************************/
#pragma once
 
#include <tracking/trackingUtilities/geometry/SZLine.h>
 
#include <tracking/trackingUtilities/geometry/SZParameters.h>
 
#include <Math/Vector2D.h>
 
#include <cstddef>
#include <iosfwd>
 
namespace Belle2 {
 
  namespace TrackingUtilities {

    class UncertainSZLine {
 
    public:
      UncertainSZLine()
      {
      }

      UncertainSZLine(const double tanLambda,
                      const double z0,
                      const SZCovariance& szCovariance = SZUtil::identity(),
                      const double chi2 = 0.0,
                      const size_t ndf = 0)
        : m_szLine(tanLambda, z0)
        , m_szCovariance(szCovariance)
        , m_chi2(chi2)
        , m_ndf(ndf)
      {
      }

      explicit UncertainSZLine(const SZParameters szParameters,
                               const SZCovariance& szCovariance = SZUtil::identity(),
                               const double chi2 = 0.0,
                               const size_t ndf = 0)
        : m_szLine(szParameters)
        , m_szCovariance(szCovariance)
        , m_chi2(chi2)
        , m_ndf(ndf)
      {
      }

      explicit UncertainSZLine(const SZLine& szLine,
                               const SZCovariance& szCovariance = SZUtil::identity(),
                               const double chi2 = 0.0,
                               const size_t ndf = 0)
        : m_szLine(szLine)
        , m_szCovariance(szCovariance)
        , m_chi2(chi2)
        , m_ndf(ndf)
      {
      }

      const SZLine* operator->() const
      {
        return &m_szLine;
      }

      operator const SZLine& () const
      {
        return m_szLine;
      }

      const SZLine& szLine() const
      {
        return m_szLine;
      }

      SZParameters szParameters() const
      {
        return m_szLine.szParameters();
      }
 
    public:
      void setSZCovariance(const SZCovariance& szCovariance)
      {
        m_szCovariance = szCovariance;
      }

      const SZCovariance& szCovariance() const
      {
        return m_szCovariance;
      }

      double covariance(const ESZParameter& iRow, const ESZParameter& iCol) const
      {
        return szCovariance()(iRow, iCol);
      }

      double variance(const ESZParameter& i) const
      {
        return szCovariance()(i, i);
      }

      double chi2() const
      {
        return m_chi2;
      }

      void setChi2(const double chi2)
      {
        m_chi2 = chi2;
      }

      std::size_t ndf() const
      {
        return m_ndf;
      }

      void setNDF(std::size_t ndf)
      {
        m_ndf = ndf;
      }

      void invalidate()
      {
        m_szLine.invalidate();
        m_szCovariance = SZUtil::identity();
        m_chi2 = 0.0;
        m_ndf = 0;
      }
 
    public:
      void reverse()
      {
        m_szLine.reverse();
        SZUtil::reverse(m_szCovariance);
      }

      UncertainSZLine reversed() const
      {
        return UncertainSZLine(m_szLine.reversed(), SZUtil::reversed(szCovariance()), chi2(), ndf());
      }
 
    public:
      void passiveMoveBy(const ROOT::Math::XYVector& bySZ)
      {
        // Move the covariance matrix first to have access to the original parameters
        SZJacobian jacobian = m_szLine.passiveMoveByJacobian(bySZ);
        SZUtil::transport(jacobian, m_szCovariance);
        m_szLine.passiveMoveBy(bySZ);
      }

      SZCovariance passiveMovedCovarianceBy(const ROOT::Math::XYVector& bySZ) const
      {
        SZJacobian jacobian = m_szLine.passiveMoveByJacobian(bySZ);
        return SZUtil::transported(jacobian, szCovariance());
      }
 
    private:
      SZLine m_szLine;

      SZCovariance m_szCovariance = SZUtil::identity();

      double m_chi2 = 0.0;

      size_t m_ndf = 0;
    };

    std::ostream& operator<<(std::ostream& output, const UncertainSZLine& uncertainSZLine);
  }
}