Abstract base class for constraints of kinematic fits. More...
#include <TrackConstraint.h>
Public Member Functions | |
| TrackConstraint () | |
| Creates an empty TrackConstraint object. | |
| virtual | ~TrackConstraint () |
| Virtual destructor. | |
| virtual void | setFOList (std::vector< TrackFitObject * > *fitobjects_) |
| Adds several TrackFitObject objects to the list. More... | |
| virtual void | addToFOList (TrackFitObject &fitobject, int flag=1) |
| Adds one TrackFitObject objects to the list. | |
| virtual double | getValue () const =0 |
| Returns the value of the constraint. | |
| virtual void | getDerivatives (int idim, double der[]) const =0 |
| Get first order derivatives. More... | |
| 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 matrix. 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. | |
| virtual void | invalidateCache () const |
| Invalidates any cached values for the next event. | |
 Public Member Functions inherited from BaseConstraint | |
| BaseConstraint () | |
| Creates an empty BaseConstraint object. | |
| BaseConstraint (const BaseConstraint &rhs) | |
| Copy constructor. More... | |
| BaseConstraint & | operator= (const BaseConstraint &rhs) |
| Assignment. More... | |
| virtual | ~BaseConstraint () |
| Virtual destructor. | |
| virtual double | getError () const |
| Returns the error on the value of the constraint. | |
| 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... | |
Protected Types | |
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typedef std::vector < TrackFitObject * > | FitObjectContainer |
| Vector of pointers to TrackFitObjects. | |
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typedef FitObjectContainer::iterator | FitObjectIterator |
| Iterator through vector of pointers to TrackFitObjects. | |
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typedef FitObjectContainer::const_iterator | ConstFitObjectIterator |
| Constant iterator through vector of pointers to TrackFitObjects. | |
Protected Attributes | |
| 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... | |
| std::vector< double > | sign |
| int | globalNum |
| Position of constraint in global constraint list. | |
| Protected Attributes inherited from BaseConstraint | |
| char * | name |
Additional Inherited Members | |
| Related Functions inherited from BaseConstraint | |
| std::ostream & | operator<< (std::ostream &os, const BaseConstraint &bc) |
| Prints out a BaseConstraint, using its print method. More... | |
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 TrackFitObject and can be either set a whole (setFOList) or enlarged by adding a single TrackFitObject (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: Benno List, Jenny List
- Date:
- 2008/01/30 09:14:54
- Author:
- blist
Member Function Documentation
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inlinevirtual |
Adds first order derivatives to global covariance matrix M.
- Parameters
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M Covariance matrix, at least idim x idim idim First dimension of the array
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inlinevirtual |
Adds second order derivatives to global covariance matrix M.
- Parameters
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M Global covariance matrix, dimension at least idim x idim idim First dimension of array der lambda Lagrange multiplier for this constraint
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inlinevirtual |
Add lambda times derivatives of chi squared to global derivative matrix.
- Parameters
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y Vector of chi2 derivatives idim Vector size
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pure virtual |
Get first order derivatives.
Call this with a predefined array "der" with the necessary number of entries!
Implements BaseConstraint.
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inlinevirtual |
Adds several TrackFitObject objects to the list.
- Parameters
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fitobjects_ A list of BaseFitObject objects
References fitobjects, and flags.
Member Data Documentation
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protected |
The flags can be used to divide the FitObjectContainer into several subsets used for example to implement an equal mass constraint (see MassConstraint).
Referenced by addToFOList(), and setFOList().
The documentation for this class was generated from the following file:
