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FastJet 3.0.2
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FastJet 3.0.2
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Background Estimator based on the median pt/area of a set of grid cells. More...
#include <fastjet/tools/GridMedianBackgroundEstimator.hh>
Public Member Functions | |
constructors and destructors | |
| GridMedianBackgroundEstimator (double ymax, double requested_grid_spacing) | |
setting a new event | |
| void | set_particles (const std::vector< PseudoJet > &particles) |
| tell the background estimator that it has a new event, composed of the specified particles. | |
retrieving fundamental information | |
| double | rho () const |
| returns rho, the median background density per unit area | |
| double | sigma () const |
| returns sigma, the background fluctuations per unit area; must be multipled by sqrt(area) to get fluctuations for a region of a given area. | |
| double | rho (const PseudoJet &jet) |
| returns rho, the background density per unit area, locally at the position of a given jet. | |
| double | sigma (const PseudoJet &jet) |
| returns sigma, the background fluctuations per unit area, locally at the position of a given jet. | |
| bool | has_sigma () |
| returns true if this background estimator has support for determination of sigma | |
| double | mean_area () const |
| returns the area of the grid cells (all identical, but referred to as "mean" area for uniformity with JetMedianBGE). | |
configuring the behaviour | |
| virtual void | set_rescaling_class (const FunctionOfPseudoJet< double > *rescaling_class) |
| Set a pointer to a class that calculates the rescaling factor as a function of the jet (position). | |
description | |
| std::string | description () const |
| returns a textual description of the background estimator | |
Background Estimator based on the median pt/area of a set of grid cells.
Description of the method: This background estimator works by projecting the event onto a grid in rapidity and azimuth. In each grid cell, the scalar pt sum of the particles in the cell is computed. The background density is then estimated by the median of (scalar pt sum/cell area) for all cells.
Parameters: The class takes 2 arguments: the absolute rapidity extent of the cells and the size of the grid cells. Note that the size of the cell will be adjusted in azimuth to satisfy the 2pi periodicity and in rapidity to match the requested rapidity extent.
Rescaling: It is possible to use a rescaling profile. In this case, the profile needs to be set before setting the particles and it will be applied to each particle (i.e. not to each cell). Note also that in this case one needs to call rho(jet) instead of rho() [Without rescaling, they are identical]
Definition at line 63 of file GridMedianBackgroundEstimator.hh.
| fastjet::GridMedianBackgroundEstimator::GridMedianBackgroundEstimator | ( | double | ymax, |
| double | requested_grid_spacing | ||
| ) | [inline] |
| ymax | maximal absolute rapidity extent of the grid |
| requested_grid_spacing | size of the grid cell. The "real" cell size could differ due e.g. to the 2pi periodicity in azimuthal angle (size, not area) |
Definition at line 72 of file GridMedianBackgroundEstimator.hh.
| void fastjet::GridMedianBackgroundEstimator::set_particles | ( | const std::vector< PseudoJet > & | particles | ) | [virtual] |
tell the background estimator that it has a new event, composed of the specified particles.
Implements fastjet::BackgroundEstimatorBase.
| double fastjet::GridMedianBackgroundEstimator::sigma | ( | ) | const [virtual] |
returns sigma, the background fluctuations per unit area; must be multipled by sqrt(area) to get fluctuations for a region of a given area.
Reimplemented from fastjet::BackgroundEstimatorBase.
Definition at line 71 of file GridMedianBackgroundEstimator.cc.
| double fastjet::GridMedianBackgroundEstimator::rho | ( | const PseudoJet & | jet | ) | [virtual] |
returns rho, the background density per unit area, locally at the position of a given jet.
Note that this is not const, because a user may then wish to query other aspects of the background that could depend on the position of the jet last used for a rho(jet) determination.
Implements fastjet::BackgroundEstimatorBase.
Definition at line 86 of file GridMedianBackgroundEstimator.cc.
| double fastjet::GridMedianBackgroundEstimator::sigma | ( | const PseudoJet & | jet | ) | [virtual] |
returns sigma, the background fluctuations per unit area, locally at the position of a given jet.
As for rho(jet), it is non-const.
Reimplemented from fastjet::BackgroundEstimatorBase.
Definition at line 96 of file GridMedianBackgroundEstimator.cc.
| double fastjet::GridMedianBackgroundEstimator::mean_area | ( | ) | const [inline] |
returns the area of the grid cells (all identical, but referred to as "mean" area for uniformity with JetMedianBGE).
Definition at line 118 of file GridMedianBackgroundEstimator.hh.
| void fastjet::GridMedianBackgroundEstimator::set_rescaling_class | ( | const FunctionOfPseudoJet< double > * | rescaling_class | ) | [virtual] |
Set a pointer to a class that calculates the rescaling factor as a function of the jet (position).
Note that the rescaling factor is used both in the determination of the "global" rho (the pt/A of each jet is divided by this factor) and when asking for a local rho (the result is multiplied by this factor).
The BackgroundRescalingYPolynomial class can be used to get a rescaling that depends just on rapidity.
Note that this has to be called BEFORE any attempt to do an actual computation
Reimplemented from fastjet::BackgroundEstimatorBase.
Definition at line 134 of file GridMedianBackgroundEstimator.cc.
1.7.4
