<html><head><meta name="color-scheme" content="light dark"></head><body><pre style="word-wrap: break-word; white-space: pre-wrap;">\section{Base\-Hard\-Constraint Class Reference}
\label{classBaseHardConstraint}\index{Base\-Hard\-Constraint@{Base\-Hard\-Constraint}}


Abstract base class for constraints of kinematic fits.  




{\ttfamily \#include $&lt;$Base\-Hard\-Constraint.\-h$&gt;$}

Inheritance diagram for Base\-Hard\-Constraint\-:\begin{figure}[H]
\begin{center}
\leavevmode
\includegraphics[height=4.000000cm]{classBaseHardConstraint}
\end{center}
\end{figure}
\subsection*{Public Member Functions}
\begin{DoxyCompactItemize}
\item 
virtual {\bf $\sim$\-Base\-Hard\-Constraint} ()\label{classBaseHardConstraint_a19ff955fa86192e281c04e75b898a5de}

\begin{DoxyCompactList}\small\item\em Virtual destructor. \end{DoxyCompactList}\item 
virtual void {\bf add1st\-Derivatives\-To\-Matrix} (double $\ast$M, int idim) const 
\begin{DoxyCompactList}\small\item\em Adds first order derivatives to global covariance matrix M. \end{DoxyCompactList}\item 
virtual void {\bf add2nd\-Derivatives\-To\-Matrix} (double $\ast$M, int idim, double lambda) const 
\begin{DoxyCompactList}\small\item\em Adds second order derivatives to global covariance matrix M. \end{DoxyCompactList}\item 
virtual void {\bf add\-To\-Global\-Chi2\-Der\-Vector} (double $\ast$y, int idim, double lambda) const 
\begin{DoxyCompactList}\small\item\em Add lambda times derivatives of chi squared to global derivative vector. \end{DoxyCompactList}\item 
virtual double {\bf dir\-Der} (double $\ast$p, double $\ast$w, int idim, double mu=1)
\begin{DoxyCompactList}\small\item\em Calculate directional derivative. \end{DoxyCompactList}\item 
virtual double {\bf dir\-Der\-Abs} (double $\ast$p, double $\ast$w, int idim, double mu=1)
\begin{DoxyCompactList}\small\item\em Calculate directional derivative for abs(c) \end{DoxyCompactList}\item 
virtual bool {\bf second\-Derivatives} (int i, int j, double $\ast${\bf derivatives}) const =0
\begin{DoxyCompactList}\small\item\em Second derivatives with respect to the meta-\/variables of Fit objects i and j; result false if all derivatives are zero. \end{DoxyCompactList}\item 
virtual bool {\bf first\-Derivatives} (int i, double $\ast${\bf derivatives}) const =0
\begin{DoxyCompactList}\small\item\em First derivatives with respect to the meta-\/variables of Fit objects i; result false if all derivatives are zero. \end{DoxyCompactList}\item 
virtual int {\bfseries get\-Var\-Basis} () const =0\label{classBaseHardConstraint_ad3ca4cdd8205971042c1e55e8a2e4bab}

\item 
virtual double {\bf get\-Value} () const =0\label{classBaseHardConstraint_a8bd0ef1e6c92d738714b9afca13067e8}

\begin{DoxyCompactList}\small\item\em Returns the value of the constraint. \end{DoxyCompactList}\item 
virtual double {\bf get\-Error} () const \label{classBaseHardConstraint_a133c6127d26e55239d9579afc6dc1354}

\begin{DoxyCompactList}\small\item\em Returns the error on the value of the constraint. \end{DoxyCompactList}\item 
virtual void {\bf get\-Derivatives} (int idim, double der[$\,$]) const =0
\begin{DoxyCompactList}\small\item\em Get first order derivatives. \end{DoxyCompactList}\item 
virtual int {\bf get\-Global\-Num} () const \label{classBaseHardConstraint_a4a8162422a862a7433530e75486bba94}

\begin{DoxyCompactList}\small\item\em Accesses position of constraint in global constraint list. \end{DoxyCompactList}\item 
virtual void {\bf set\-Global\-Num} (int iglobal)
\begin{DoxyCompactList}\small\item\em Sets position of constraint in global constraint list. \end{DoxyCompactList}\item 
virtual void {\bfseries print\-First\-Derivatives} () const \label{classBaseHardConstraint_a7feed0965587edfbcd715f3ef781a742}

\item 
virtual void {\bfseries print\-Second\-Derivatives} () const \label{classBaseHardConstraint_ade907c4a5ceca7c848b9052acaddcd4c}

\item 
virtual void {\bfseries test1st\-Derivatives} ()\label{classBaseHardConstraint_a88d429f7794f430e406d42011165e475}

\item 
virtual void {\bfseries test2nd\-Derivatives} ()\label{classBaseHardConstraint_af2879251127211cbb7edd9e0b9648f54}

\item 
virtual double {\bf num1st\-Derivative} (int ifo, int ilocal, double eps)
\begin{DoxyCompactList}\small\item\em Evaluates numerically the 1st derivative w.\-r.\-t. a parameter. \end{DoxyCompactList}\item 
virtual double {\bf num2nd\-Derivative} (int ifo1, int ilocal1, double eps1, int ifo2, int ilocal2, double eps2)
\begin{DoxyCompactList}\small\item\em Evaluates numerically the 2nd derivative w.\-r.\-t. 2 parameters. \end{DoxyCompactList}\end{DoxyCompactItemize}
\subsection*{Protected Types}
\begin{DoxyCompactItemize}
\item 
typedef std\-::vector\\*
$&lt;$ {\bf Base\-Fit\-Object} $\ast$ $&gt;$ {\bf Fit\-Object\-Container}\label{classBaseHardConstraint_ac6b4966145b8f25632ef543b392cca9e}

\begin{DoxyCompactList}\small\item\em Vector of pointers to Particle\-Fit\-Objects. \end{DoxyCompactList}\item 
typedef \\*
Fit\-Object\-Container\-::iterator {\bf Fit\-Object\-Iterator}\label{classBaseHardConstraint_a4862e12b5fa2da37b2b4de5f98dcecf1}

\begin{DoxyCompactList}\small\item\em Iterator through vector of pointers to Particle\-Fit\-Objects. \end{DoxyCompactList}\item 
typedef \\*
Fit\-Object\-Container\-::const\-\_\-iterator {\bf Const\-Fit\-Object\-Iterator}\label{classBaseHardConstraint_a2bbc77884bde2f4ebf6437147917fde5}

\begin{DoxyCompactList}\small\item\em Constant iterator through vector of pointers to Particle\-Fit\-Objects. \end{DoxyCompactList}\end{DoxyCompactItemize}
\subsection*{Protected Attributes}
\begin{DoxyCompactItemize}
\item 
{\bf Fit\-Object\-Container} {\bf fitobjects}\label{classBaseHardConstraint_a96c9306f0e7a0be38d035cf4a557dbfe}

\begin{DoxyCompactList}\small\item\em The Fit\-Object\-Container. \end{DoxyCompactList}\item 
std\-::vector$&lt;$ double $&gt;$ {\bf derivatives}\label{classBaseHardConstraint_a1bdd3208f3f3c55406f8c4b34a515647}

\begin{DoxyCompactList}\small\item\em The derivatives. \end{DoxyCompactList}\item 
std\-::vector$&lt;$ int $&gt;$ {\bf flags}
\begin{DoxyCompactList}\small\item\em The flags can be used to divide the Fit\-Object\-Container into several subsets used for example to implement an equal mass constraint (see \doxyref{Mass\-Constraint}{p.}{classMassConstraint}). \end{DoxyCompactList}\item 
int {\bf global\-Num}\label{classBaseHardConstraint_a1eddc7147da6bf2ea9893165dc68bc5a}

\begin{DoxyCompactList}\small\item\em Position of constraint in global constraint list. \end{DoxyCompactList}\end{DoxyCompactItemize}
\subsection*{Additional Inherited Members}


\subsection{Detailed Description}
Abstract base class for constraints of kinematic fits. 

This class defines the minimal functionality any constraint class must provide. First of all a constraint should know on with particles (or Fit\-Object) it is applied. Where as for example a constraint on the total transvese momentum takes into account all particles in the event, an invariant mass constraint usually applies only to a subset of particles.

The particle list is implemented as a vector containing pointers to objects derived from \doxyref{Base\-Fit\-Object}{p.}{classBaseFitObject} and can be either set a whole (set\-F\-O\-List) or enlarged by adding a single \doxyref{Base\-Fit\-Object}{p.}{classBaseFitObject} (add\-To\-F\-O\-List).

From the four--momenta of all concerned fit objects the constraint has to be able to calculate its current value (get\-Value). Constraints should be formulated such that a value of zero corresponds to a perfectly fulfilled constraint.

In order to find a solution to the constrained minimisation problem, fit algorithms usually need the first order derivatives of the constraint with respect to the fit parameters. Since many constraints can be most easily expressed in terms of E, px, py, pz, the constraints supply their derivatives w.\-r.\-t. these parameters. If a Fit\-Object uses a different parametrisation, it is its own task to provide the additional derivatives of E, px, py, pz w.\-r.\-t. the parameters of the Fit\-Object. Thus it is easily possible to use Fit\-Objects with different kinds of parametrisations under the same constraint. Some fit algorithms also need the second derivatives of the constraint, i.\-e. the Newton\-Fitter.

First and second order derivatives of each constraint can be added directly to the global covariance matrix containing the derivatives of all constraints w.\-r.\-t. to all parameters (add1st\-Derivatives\-To\-Matrix, add2nd\-Derivatives\-To\-Matrix). This requires the constraint to know its position in the overall list of constraints (global\-Num).

Author\-: Jenny List, Benno List Last update\-: \begin{DoxyParagraph}{Date\-:}
2011/03/03 15\-:03\-:02 
\end{DoxyParagraph}
by\-: \begin{DoxyParagraph}{Author\-:}
blist 
\end{DoxyParagraph}


\subsection{Member Function Documentation}
\index{Base\-Hard\-Constraint@{Base\-Hard\-Constraint}!add1st\-Derivatives\-To\-Matrix@{add1st\-Derivatives\-To\-Matrix}}
\index{add1st\-Derivatives\-To\-Matrix@{add1st\-Derivatives\-To\-Matrix}!BaseHardConstraint@{Base\-Hard\-Constraint}}
\subsubsection[{add1st\-Derivatives\-To\-Matrix}]{\setlength{\rightskip}{0pt plus 5cm}void Base\-Hard\-Constraint\-::add1st\-Derivatives\-To\-Matrix (
\begin{DoxyParamCaption}
\item[{double $\ast$}]{M, }
\item[{int}]{idim}
\end{DoxyParamCaption}
) const\hspace{0.3cm}{\ttfamily [virtual]}}\label{classBaseHardConstraint_a526658add2437e6979914cd8475e0bb7}


Adds first order derivatives to global covariance matrix M. 


\begin{DoxyParams}{Parameters}
{\em M} &amp; Global covariance matrix, dimension at least idim x idim \\
\hline
{\em idim} &amp; First dimension of array der \\
\hline
\end{DoxyParams}


References first\-Derivatives(), fitobjects, and get\-Global\-Num().

\index{Base\-Hard\-Constraint@{Base\-Hard\-Constraint}!add2nd\-Derivatives\-To\-Matrix@{add2nd\-Derivatives\-To\-Matrix}}
\index{add2nd\-Derivatives\-To\-Matrix@{add2nd\-Derivatives\-To\-Matrix}!BaseHardConstraint@{Base\-Hard\-Constraint}}
\subsubsection[{add2nd\-Derivatives\-To\-Matrix}]{\setlength{\rightskip}{0pt plus 5cm}void Base\-Hard\-Constraint\-::add2nd\-Derivatives\-To\-Matrix (
\begin{DoxyParamCaption}
\item[{double $\ast$}]{M, }
\item[{int}]{idim, }
\item[{double}]{lambda}
\end{DoxyParamCaption}
) const\hspace{0.3cm}{\ttfamily [virtual]}}\label{classBaseHardConstraint_a622e97c000f58cd3aa4a0b4f970f4e8c}


Adds second order derivatives to global covariance matrix M. 

Calculates the second derivative of the constraint g w.\-r.\-t.

the various parameters, multiplies it by lambda and adds it to the global covariance matrix

in case of particlefitobject\-: We denote with P\-\_\-i the 4-\/vector of the i-\/th \doxyref{Particle\-Fit\-Object}{p.}{classParticleFitObject}, then \$\$ \{ $^\wedge$2 g\}\{ a\-\_\-k  a\-\_\-l\} =   \{ $^\wedge$2 g\}\{ P\-\_\-i  P\-\_\-j\}  \{ P\-\_\-i\}\{ a\-\_\-k\}  \{ P\-\_\-j\}\{ a\-\_\-l\}
\begin{DoxyItemize}
\item \{ g\}\{ P\-\_\-i\}  \{$^\wedge$2 P\-\_\-i\}\{ a\-\_\-k  a\-\_\-l\} \$\$ Here, \$\{ P\-\_\-i\}\{ a\-\_\-k\}\$ is a \$4  n\-\_\-i\$ Matrix, where \$n\-\_\-i\$ is the number of parameters of Fit\-Object i; Correspondingly, \$\{$^\wedge$2 P\-\_\-i\}\{ a\-\_\-k  a\-\_\-l\}\$ is a \$4  n\-\_\-i  n\-\_\-i\$ matrix. Also, \$\{ $^\wedge$2 g\}\{ P\-\_\-i  P\-\_\-j\}\$ is a \$4 4\$ matrix for a given i and j, and \$\{ g\}\{ P\-\_\-i\}\$ is a 4-\/vector (though not a Lorentz-\/vector!).
\end{DoxyItemize}

but here it's been generalised First, treat the part \$\$ \{ $^\wedge$2 g\}\{ P\-\_\-i  P\-\_\-j\}  \{ P\-\_\-i\}\{ a\-\_\-k\}  \{ P\-\_\-j\}\{ a\-\_\-l\} \$\$

Second, treat the part \$\$  \{ g\}\{ P\-\_\-i\}  \{$^\wedge$2 P\-\_\-i\}\{ a\-\_\-k  a\-\_\-l\} \$\$ Here, \$\{ g\}\{ P\-\_\-i\}\$ is a 4-\/vector, which we pass on to the Fit\-Object
\begin{DoxyParams}{Parameters}
{\em M} &amp; Global covariance matrix, dimension at least idim x idim \\
\hline
{\em idim} &amp; First dimension of array der \\
\hline
{\em lambda} &amp; Lagrange multiplier for this constraint \\
\hline
\end{DoxyParams}


References first\-Derivatives(), fitobjects, Base\-Fit\-Object\-::get\-Global\-Par\-Num(), Base\-Fit\-Object\-::get\-N\-Par(), and second\-Derivatives().

\index{Base\-Hard\-Constraint@{Base\-Hard\-Constraint}!add\-To\-Global\-Chi2\-Der\-Vector@{add\-To\-Global\-Chi2\-Der\-Vector}}
\index{add\-To\-Global\-Chi2\-Der\-Vector@{add\-To\-Global\-Chi2\-Der\-Vector}!BaseHardConstraint@{Base\-Hard\-Constraint}}
\subsubsection[{add\-To\-Global\-Chi2\-Der\-Vector}]{\setlength{\rightskip}{0pt plus 5cm}void Base\-Hard\-Constraint\-::add\-To\-Global\-Chi2\-Der\-Vector (
\begin{DoxyParamCaption}
\item[{double $\ast$}]{y, }
\item[{int}]{idim, }
\item[{double}]{lambda}
\end{DoxyParamCaption}
) const\hspace{0.3cm}{\ttfamily [virtual]}}\label{classBaseHardConstraint_ab0e3bd8ad7626e62199824f284bcf92b}


Add lambda times derivatives of chi squared to global derivative vector. 


\begin{DoxyParams}{Parameters}
{\em y} &amp; Vector of chi2 derivatives \\
\hline
{\em idim} &amp; Vector size \\
\hline
\end{DoxyParams}


References Base\-Fit\-Object\-::add\-To\-Global\-Chi2\-Der\-Vector(), first\-Derivatives(), and fitobjects.



Referenced by dir\-Der().

\index{Base\-Hard\-Constraint@{Base\-Hard\-Constraint}!dir\-Der@{dir\-Der}}
\index{dir\-Der@{dir\-Der}!BaseHardConstraint@{Base\-Hard\-Constraint}}
\subsubsection[{dir\-Der}]{\setlength{\rightskip}{0pt plus 5cm}double Base\-Hard\-Constraint\-::dir\-Der (
\begin{DoxyParamCaption}
\item[{double $\ast$}]{p, }
\item[{double $\ast$}]{w, }
\item[{int}]{idim, }
\item[{double}]{mu = {\ttfamily 1}}
\end{DoxyParamCaption}
)\hspace{0.3cm}{\ttfamily [virtual]}}\label{classBaseHardConstraint_aa01e09720826749ad05a53206b3be83d}


Calculate directional derivative. 


\begin{DoxyParams}{Parameters}
{\em p} &amp; Vector of direction \\
\hline
{\em w} &amp; Work vector \\
\hline
{\em idim} &amp; Vector size \\
\hline
{\em mu} &amp; optional multiplier \\
\hline
\end{DoxyParams}


References add\-To\-Global\-Chi2\-Der\-Vector().



Referenced by dir\-Der\-Abs().

\index{Base\-Hard\-Constraint@{Base\-Hard\-Constraint}!dir\-Der\-Abs@{dir\-Der\-Abs}}
\index{dir\-Der\-Abs@{dir\-Der\-Abs}!BaseHardConstraint@{Base\-Hard\-Constraint}}
\subsubsection[{dir\-Der\-Abs}]{\setlength{\rightskip}{0pt plus 5cm}double Base\-Hard\-Constraint\-::dir\-Der\-Abs (
\begin{DoxyParamCaption}
\item[{double $\ast$}]{p, }
\item[{double $\ast$}]{w, }
\item[{int}]{idim, }
\item[{double}]{mu = {\ttfamily 1}}
\end{DoxyParamCaption}
)\hspace{0.3cm}{\ttfamily [virtual]}}\label{classBaseHardConstraint_a482aec4df55c6b4b0c2b498ebadc0ed7}


Calculate directional derivative for abs(c) 


\begin{DoxyParams}{Parameters}
{\em p} &amp; Vector of direction \\
\hline
{\em w} &amp; Work vector \\
\hline
{\em idim} &amp; Vector size \\
\hline
{\em mu} &amp; optional multiplier \\
\hline
\end{DoxyParams}


References dir\-Der(), and get\-Value().

\index{Base\-Hard\-Constraint@{Base\-Hard\-Constraint}!first\-Derivatives@{first\-Derivatives}}
\index{first\-Derivatives@{first\-Derivatives}!BaseHardConstraint@{Base\-Hard\-Constraint}}
\subsubsection[{first\-Derivatives}]{\setlength{\rightskip}{0pt plus 5cm}virtual bool Base\-Hard\-Constraint\-::first\-Derivatives (
\begin{DoxyParamCaption}
\item[{int}]{i, }
\item[{double $\ast$}]{derivatives}
\end{DoxyParamCaption}
) const\hspace{0.3cm}{\ttfamily [pure virtual]}}\label{classBaseHardConstraint_a26b5d72caf3176a1568c9327e309700f}


First derivatives with respect to the meta-\/variables of Fit objects i; result false if all derivatives are zero. 


\begin{DoxyParams}{Parameters}
{\em i} &amp; number of 1st Fit\-Object \\
\hline
{\em derivatives} &amp; The result 4-\/vector \\
\hline
\end{DoxyParams}


Implemented in {\bf Momentum\-Constraint} \doxyref{}{p.}{classMomentumConstraint_a299c5fed7afced190353b0d5d6b5f956}, {\bf Mass\-Constraint} \doxyref{}{p.}{classMassConstraint_a34d109902ee62777c22aca1ae7ad202b}, and {\bf Vertex\-Constraint} \doxyref{}{p.}{classVertexConstraint_a90cd39152bb5491c97a437ccc8ee52e1}.



Referenced by add1st\-Derivatives\-To\-Matrix(), add2nd\-Derivatives\-To\-Matrix(), add\-To\-Global\-Chi2\-Der\-Vector(), and get\-Error().

\index{Base\-Hard\-Constraint@{Base\-Hard\-Constraint}!get\-Derivatives@{get\-Derivatives}}
\index{get\-Derivatives@{get\-Derivatives}!BaseHardConstraint@{Base\-Hard\-Constraint}}
\subsubsection[{get\-Derivatives}]{\setlength{\rightskip}{0pt plus 5cm}virtual void Base\-Hard\-Constraint\-::get\-Derivatives (
\begin{DoxyParamCaption}
\item[{int}]{idim, }
\item[{double}]{der[$\,$]}
\end{DoxyParamCaption}
) const\hspace{0.3cm}{\ttfamily [pure virtual]}}\label{classBaseHardConstraint_aece9761955facf0914a59888c0253762}


Get first order derivatives. 

Call this with a predefined array \char`\"{}der\char`\"{} with the necessary number of entries! 
\begin{DoxyParams}{Parameters}
{\em idim} &amp; First dimension of the array \\
\hline
{\em der} &amp; Array of derivatives, at least idim x idim \\
\hline
\end{DoxyParams}


Implements {\bf Base\-Constraint} \doxyref{}{p.}{classBaseConstraint_a01d60bff974a2926521838c640373d7f}.



Implemented in {\bf Mass\-Constraint} \doxyref{}{p.}{classMassConstraint_a113296332c73d15125e4f6d53302e569}, {\bf Momentum\-Constraint} \doxyref{}{p.}{classMomentumConstraint_a60fa38a84077150d36297709ae812dc6}, and {\bf Vertex\-Constraint} \doxyref{}{p.}{classVertexConstraint_a645caac70b3706fbf78c9651167aecb3}.

\index{Base\-Hard\-Constraint@{Base\-Hard\-Constraint}!num1st\-Derivative@{num1st\-Derivative}}
\index{num1st\-Derivative@{num1st\-Derivative}!BaseHardConstraint@{Base\-Hard\-Constraint}}
\subsubsection[{num1st\-Derivative}]{\setlength{\rightskip}{0pt plus 5cm}double Base\-Hard\-Constraint\-::num1st\-Derivative (
\begin{DoxyParamCaption}
\item[{int}]{ifo, }
\item[{int}]{ilocal, }
\item[{double}]{eps}
\end{DoxyParamCaption}
)\hspace{0.3cm}{\ttfamily [virtual]}}\label{classBaseHardConstraint_af15974e742659c6241e1d54bca0ef8db}


Evaluates numerically the 1st derivative w.\-r.\-t. a parameter. 


\begin{DoxyParams}{Parameters}
{\em ifo} &amp; Number of Fit\-Object \\
\hline
{\em ilocal} &amp; Local parameter number \\
\hline
{\em eps} &amp; variation of local parameter \\
\hline
\end{DoxyParams}


References fitobjects, Base\-Fit\-Object\-::get\-Param(), get\-Value(), and Base\-Fit\-Object\-::set\-Param().

\index{Base\-Hard\-Constraint@{Base\-Hard\-Constraint}!num2nd\-Derivative@{num2nd\-Derivative}}
\index{num2nd\-Derivative@{num2nd\-Derivative}!BaseHardConstraint@{Base\-Hard\-Constraint}}
\subsubsection[{num2nd\-Derivative}]{\setlength{\rightskip}{0pt plus 5cm}double Base\-Hard\-Constraint\-::num2nd\-Derivative (
\begin{DoxyParamCaption}
\item[{int}]{ifo1, }
\item[{int}]{ilocal1, }
\item[{double}]{eps1, }
\item[{int}]{ifo2, }
\item[{int}]{ilocal2, }
\item[{double}]{eps2}
\end{DoxyParamCaption}
)\hspace{0.3cm}{\ttfamily [virtual]}}\label{classBaseHardConstraint_a6acb333d0d8375c7868d4f88b0c87593}


Evaluates numerically the 2nd derivative w.\-r.\-t. 2 parameters. 


\begin{DoxyParams}{Parameters}
{\em ifo1} &amp; Number of 1st Fit\-Object \\
\hline
{\em ilocal1} &amp; 1st local parameter number \\
\hline
{\em eps1} &amp; variation of 1st local parameter \\
\hline
{\em ifo2} &amp; Number of 1st Fit\-Object \\
\hline
{\em ilocal2} &amp; 1st local parameter number \\
\hline
{\em eps2} &amp; variation of 2nd local parameter \\
\hline
\end{DoxyParams}


References fitobjects, Base\-Fit\-Object\-::get\-Param(), get\-Value(), and Base\-Fit\-Object\-::set\-Param().

\index{Base\-Hard\-Constraint@{Base\-Hard\-Constraint}!second\-Derivatives@{second\-Derivatives}}
\index{second\-Derivatives@{second\-Derivatives}!BaseHardConstraint@{Base\-Hard\-Constraint}}
\subsubsection[{second\-Derivatives}]{\setlength{\rightskip}{0pt plus 5cm}virtual bool Base\-Hard\-Constraint\-::second\-Derivatives (
\begin{DoxyParamCaption}
\item[{int}]{i, }
\item[{int}]{j, }
\item[{double $\ast$}]{derivatives}
\end{DoxyParamCaption}
) const\hspace{0.3cm}{\ttfamily [pure virtual]}}\label{classBaseHardConstraint_afc5d5695e93d9f68647dbdd33dc3637d}


Second derivatives with respect to the meta-\/variables of Fit objects i and j; result false if all derivatives are zero. 


\begin{DoxyParams}{Parameters}
{\em i} &amp; number of 1st Fit\-Object \\
\hline
{\em j} &amp; number of 2nd Fit\-Object \\
\hline
{\em derivatives} &amp; The result 4x4 matrix \\
\hline
\end{DoxyParams}


Implemented in {\bf Momentum\-Constraint} \doxyref{}{p.}{classMomentumConstraint_a53ef154476fc6f44ce44dc268e0b34a5}, {\bf Mass\-Constraint} \doxyref{}{p.}{classMassConstraint_a7f466e3e3a8695ff2e29f19c3dc755fd}, and {\bf Vertex\-Constraint} \doxyref{}{p.}{classVertexConstraint_a6e27055ba33d1ac7fc6f43c6937b905a}.



Referenced by add2nd\-Derivatives\-To\-Matrix().

\index{Base\-Hard\-Constraint@{Base\-Hard\-Constraint}!set\-Global\-Num@{set\-Global\-Num}}
\index{set\-Global\-Num@{set\-Global\-Num}!BaseHardConstraint@{Base\-Hard\-Constraint}}
\subsubsection[{set\-Global\-Num}]{\setlength{\rightskip}{0pt plus 5cm}virtual void Base\-Hard\-Constraint\-::set\-Global\-Num (
\begin{DoxyParamCaption}
\item[{int}]{iglobal}
\end{DoxyParamCaption}
)\hspace{0.3cm}{\ttfamily [inline]}, {\ttfamily [virtual]}}\label{classBaseHardConstraint_a7e1fb22a4ed5edb3c1ef655f35aaa9f2}


Sets position of constraint in global constraint list. 


\begin{DoxyParams}{Parameters}
{\em iglobal} &amp; Global constraint number \\
\hline
\end{DoxyParams}


References global\-Num.



Referenced by Newton\-Fitter\-G\-S\-L\-::initialize(), and New\-Fitter\-G\-S\-L\-::initialize().



\subsection{Member Data Documentation}
\index{Base\-Hard\-Constraint@{Base\-Hard\-Constraint}!flags@{flags}}
\index{flags@{flags}!BaseHardConstraint@{Base\-Hard\-Constraint}}
\subsubsection[{flags}]{\setlength{\rightskip}{0pt plus 5cm}std\-::vector$&lt;$int$&gt;$ Base\-Hard\-Constraint\-::flags\hspace{0.3cm}{\ttfamily [protected]}}\label{classBaseHardConstraint_a9dc5d976a0fcb44222b76df0913aa4b0}


The flags can be used to divide the Fit\-Object\-Container into several subsets used for example to implement an equal mass constraint (see \doxyref{Mass\-Constraint}{p.}{classMassConstraint}). 



Referenced by Particle\-Constraint\-::add\-To\-F\-O\-List(), Mass\-Constraint\-::first\-Derivatives(), Mass\-Constraint\-::get\-Derivatives(), Mass\-Constraint\-::get\-Mass(), Mass\-Constraint\-::get\-Value(), Particle\-Constraint\-::reset\-F\-O\-List(), Mass\-Constraint\-::second\-Derivatives(), and Particle\-Constraint\-::set\-F\-O\-List().



The documentation for this class was generated from the following files\-:\begin{DoxyCompactItemize}
\item 
{\bf Base\-Hard\-Constraint.\-h}\item 
{\bf Base\-Hard\-Constraint.\-cc}\end{DoxyCompactItemize}
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