\section{marlintpc\-:\-:local\-Helix Class Reference}
\label{classmarlintpc_1_1localHelix}\index{marlintpc\-::local\-Helix@{marlintpc\-::local\-Helix}}


Local \doxyref{Helix}{p.}{classHelix}.  




{\ttfamily \#include $<$Simple\-Helix\-Track\-Model.\-h$>$}

\subsection*{Public Member Functions}
\begin{DoxyCompactItemize}
\item 
{\bf local\-Helix} (const double $\ast$, const double $\ast$, const double)
\begin{DoxyCompactList}\small\item\em Constructor. \end{DoxyCompactList}\item 
void {\bf dump} () const \label{classmarlintpc_1_1localHelix_acdf94d940376f5871852e7ebace690b5}

\begin{DoxyCompactList}\small\item\em Dump helix. \end{DoxyCompactList}\item 
T\-Matrix\-D {\bf propagate\-To} (const double $\ast$, const double)
\begin{DoxyCompactList}\small\item\em Propagate stepwise (close) to point. \end{DoxyCompactList}\item 
{\bf simple\-Helix} {\bf get\-Simple\-Helix} () const 
\begin{DoxyCompactList}\small\item\em Get simple helix. \end{DoxyCompactList}\end{DoxyCompactItemize}


\subsection{Detailed Description}
Local \doxyref{Helix}{p.}{classHelix}. 

Utilities for local helix track model build from perigee parameters and magnetic field at the P\-C\-A (point of closest approach) to the reference point, assuming constant magnetic field in arbitrary direction.

In a local system a simple helix is used. The offset of the local system is the P\-C\-A of the track (to the reference point) and the directions are (p,n,h), h is the direction of the magnetic field, n = h x t / $\vert$h x t$\vert$ with track direction t and p = n x h. The bending plane is defined by p and n and p is the local track direction at the P\-C\-A in this plane.

Implemented is a stepwise propagation in a changing (only locally constant) magnetic field.

Propagation and transformation jacobians according to Strandlie \& Wittek (N\-I\-M A 566(2006) 687-\/698)

\begin{DoxyAuthor}{Author}
C. Kleinwort, D\-E\-S\-Y (131112) 
\end{DoxyAuthor}


\subsection{Constructor \& Destructor Documentation}
\index{marlintpc\-::local\-Helix@{marlintpc\-::local\-Helix}!local\-Helix@{local\-Helix}}
\index{local\-Helix@{local\-Helix}!marlintpc::localHelix@{marlintpc\-::local\-Helix}}
\subsubsection[{local\-Helix}]{\setlength{\rightskip}{0pt plus 5cm}marlintpc\-::local\-Helix\-::local\-Helix (
\begin{DoxyParamCaption}
\item[{const double $\ast$}]{parameters, }
\item[{const double $\ast$}]{ref\-Point, }
\item[{const double}]{b\-Scale}
\end{DoxyParamCaption}
)}\label{classmarlintpc_1_1localHelix_a6bcc09b5eaaa2f3ad8ff67163ba94d5b}


Constructor. 


\begin{DoxyParams}[1]{Parameters}
\mbox{\tt in}  & {\em parameters} & (global) helix parameters (at) \\
\hline
\mbox{\tt in}  & {\em ref\-Point} & reference point \\
\hline
\mbox{\tt in}  & {\em b\-Scale} & scale factor for magnetic field (0/1) \\
\hline
\end{DoxyParams}


\subsection{Member Function Documentation}
\index{marlintpc\-::local\-Helix@{marlintpc\-::local\-Helix}!get\-Simple\-Helix@{get\-Simple\-Helix}}
\index{get\-Simple\-Helix@{get\-Simple\-Helix}!marlintpc::localHelix@{marlintpc\-::local\-Helix}}
\subsubsection[{get\-Simple\-Helix}]{\setlength{\rightskip}{0pt plus 5cm}{\bf simple\-Helix} marlintpc\-::local\-Helix\-::get\-Simple\-Helix (
\begin{DoxyParamCaption}
{}
\end{DoxyParamCaption}
) const}\label{classmarlintpc_1_1localHelix_ac45e69184f61d4ca6b25a507d3c90cbc}


Get simple helix. 

Get simple helix in global system at current reference point.

\begin{DoxyReturn}{Returns}
simple helix 
\end{DoxyReturn}
\index{marlintpc\-::local\-Helix@{marlintpc\-::local\-Helix}!propagate\-To@{propagate\-To}}
\index{propagate\-To@{propagate\-To}!marlintpc::localHelix@{marlintpc\-::local\-Helix}}
\subsubsection[{propagate\-To}]{\setlength{\rightskip}{0pt plus 5cm}T\-Matrix\-D marlintpc\-::local\-Helix\-::propagate\-To (
\begin{DoxyParamCaption}
\item[{const double $\ast$}]{point, }
\item[{const double}]{mstep}
\end{DoxyParamCaption}
)}\label{classmarlintpc_1_1localHelix_a413e32f44832b3f2109645e1dd845cfd}


Propagate stepwise (close) to point. 

Stepwise propagation in a changing (only locally constant) magnetic field. Reference point is changed to (P\-C\-A of) target.


\begin{DoxyParams}[1]{Parameters}
\mbox{\tt in}  & {\em point} & target (propagate to P\-C\-A) \\
\hline
\mbox{\tt in}  & {\em mstep} & maximal step size with constant magnetic field \\
\hline
\end{DoxyParams}
\begin{DoxyReturn}{Returns}
analytical propagation jacobian 
\end{DoxyReturn}


References marlintpc\-::local\-Helix\-Analytical\-Jacobian().



The documentation for this class was generated from the following files\-:\begin{DoxyCompactItemize}
\item 
Simple\-Helix\-Track\-Model.\-h\item 
Simple\-Helix\-Track\-Model.\-cc\end{DoxyCompactItemize}
