MarlinKinfit  0.4.0
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ParticleConstraint Class Reference

Abstract base class for constraints of kinematic fits. More...

#include <ParticleConstraint.h>

Inheritance diagram for ParticleConstraint:
BaseHardConstraint BaseConstraint MassConstraint MomentumConstraint

Public Member Functions

 ParticleConstraint ()
 Creates an empty ParticleConstraint object.
 
virtual ~ParticleConstraint ()
 Virtual destructor.
 
virtual void setFOList (std::vector< ParticleFitObject * > *fitobjects_)
 Adds several ParticleFitObject objects to the list. More...
 
virtual void addToFOList (ParticleFitObject &fitobject, int flag=1)
 Adds one ParticleFitObject objects to the list.
 
virtual void resetFOList ()
 Resests ParticleFitObject list.
 
virtual void invalidateCache () const
 Invalidates any cached values for the next event.
 
- Public Member Functions inherited from BaseHardConstraint
virtual ~BaseHardConstraint ()
 Virtual destructor.
 
virtual void add1stDerivativesToMatrix (double *M, int idim) const
 Adds first order derivatives to global covariance matrix M. More...
 
virtual void add2ndDerivativesToMatrix (double *M, int idim, double lambda) const
 Adds second order derivatives to global covariance matrix M. More...
 
virtual void addToGlobalChi2DerVector (double *y, int idim, double lambda) const
 Add lambda times derivatives of chi squared to global derivative vector. More...
 
virtual double dirDer (double *p, double *w, int idim, double mu=1)
 Calculate directional derivative. More...
 
virtual double dirDerAbs (double *p, double *w, int idim, double mu=1)
 Calculate directional derivative for abs(c) More...
 
virtual bool secondDerivatives (int i, int j, double *derivatives) const =0
 Second derivatives with respect to the meta-variables of Fit objects i and j; result false if all derivatives are zero. More...
 
virtual bool firstDerivatives (int i, double *derivatives) const =0
 First derivatives with respect to the meta-variables of Fit objects i; result false if all derivatives are zero. More...
 
virtual int getVarBasis () const =0
 
virtual double getValue () const =0
 Returns the value of the constraint.
 
virtual double getError () const
 Returns the error on the value of the constraint.
 
virtual void getDerivatives (int idim, double der[]) const =0
 Get first order derivatives. More...
 
virtual int getGlobalNum () const
 Accesses position of constraint in global constraint list.
 
virtual void setGlobalNum (int iglobal)
 Sets position of constraint in global constraint list. More...
 
virtual void printFirstDerivatives () const
 
virtual void printSecondDerivatives () const
 
virtual void test1stDerivatives ()
 
virtual void test2ndDerivatives ()
 
virtual double num1stDerivative (int ifo, int ilocal, double eps)
 Evaluates numerically the 1st derivative w.r.t. a parameter. More...
 
virtual double num2ndDerivative (int ifo1, int ilocal1, double eps1, int ifo2, int ilocal2, double eps2)
 Evaluates numerically the 2nd derivative w.r.t. 2 parameters. More...
 
- Public Member Functions inherited from BaseConstraint
 BaseConstraint ()
 Creates an empty BaseConstraint object.
 
 BaseConstraint (const BaseConstraint &rhs)
 Copy constructor. More...
 
BaseConstraintoperator= (const BaseConstraint &rhs)
 Assignment. More...
 
virtual ~BaseConstraint ()
 Virtual destructor.
 
virtual const char * getName () const
 Returns the name of the constraint.
 
virtual void setName (const char *name_)
 Set object's name.
 
virtual std::ostream & print (std::ostream &os) const
 print object to ostream More...
 

Additional Inherited Members

- Protected Types inherited from BaseHardConstraint
typedef std::vector
< BaseFitObject * > 
FitObjectContainer
 Vector of pointers to ParticleFitObjects.
 
typedef
FitObjectContainer::iterator 
FitObjectIterator
 Iterator through vector of pointers to ParticleFitObjects.
 
typedef
FitObjectContainer::const_iterator 
ConstFitObjectIterator
 Constant iterator through vector of pointers to ParticleFitObjects.
 
- Protected Attributes inherited from BaseHardConstraint
FitObjectContainer fitobjects
 The FitObjectContainer.
 
std::vector< double > derivatives
 The derivatives.
 
std::vector< int > flags
 The flags can be used to divide the FitObjectContainer into several subsets used for example to implement an equal mass constraint (see MassConstraint). More...
 
int globalNum
 Position of constraint in global constraint list.
 
- Protected Attributes inherited from BaseConstraint
char * name
 

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 FitObject) 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 ParticleFitObject and can be either set a whole (setFOList) or enlarged by adding a single ParticleFitObject (addToFOList).

From the four–momenta of all concerned fit objects the constraint has to be able to calculate its current value (getValue). 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 FitObject 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 FitObject. Thus it is easily possible to use FitObjects with different kinds of parametrisations under the same constraint. Some fit algorithms also need the second derivatives of the constraint, i.e. the NewtonFitter.

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 (add1stDerivativesToMatrix, add2ndDerivativesToMatrix). This requires the constraint to know its position in the overall list of constraints (globalNum).

Author: Jenny List, Benno List

Date:
2008/02/12 16:43:26
Author:
blist

Member Function Documentation

virtual void ParticleConstraint::setFOList ( std::vector< ParticleFitObject * > *  fitobjects_)
inlinevirtual

Adds several ParticleFitObject objects to the list.

Parameters
fitobjects_A list of BaseFitObject objects

References BaseHardConstraint::fitobjects, and BaseHardConstraint::flags.


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