+++ /dev/null
-//STARTHEADER
-// $Id: Dnn2piCylinder.hh 431 2007-01-20 10:44:55Z salam $
-//
-// Copyright (c) 2005-2006, Matteo Cacciari and Gavin Salam
-//
-//----------------------------------------------------------------------
-// This file is part of FastJet.
-//
-// FastJet is free software; you can redistribute it and/or modify
-// it under the terms of the GNU General Public License as published by
-// the Free Software Foundation; either version 2 of the License, or
-// (at your option) any later version.
-//
-// The algorithms that underlie FastJet have required considerable
-// development and are described in hep-ph/0512210. If you use
-// FastJet as part of work towards a scientific publication, please
-// include a citation to the FastJet paper.
-//
-// FastJet is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-// GNU General Public License for more details.
-//
-// You should have received a copy of the GNU General Public License
-// along with FastJet; if not, write to the Free Software
-// Foundation, Inc.:
-// 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
-//----------------------------------------------------------------------
-//ENDHEADER
-
-
-#ifndef DROP_CGAL // in case we do not have the code for CGAL
-#ifndef __FASTJET_DNN2PICYLINDER_HH__
-#define __FASTJET_DNN2PICYLINDER_HH__
-
-#include "fastjet/internal/DynamicNearestNeighbours.hh"
-#include "fastjet/internal/DnnPlane.hh"
-#include "fastjet/internal/numconsts.hh"
-
-namespace fastjet { // defined in fastjet/internal/base.hh
-
-
-/// class derived from DynamicNearestNeighbours that provides an
-/// implementation for the surface of cylinder (using one
-/// DnnPlane object spanning 0--2pi).
-class Dnn2piCylinder : public DynamicNearestNeighbours {
- public:
- /// empty initaliser
- Dnn2piCylinder() {}
-
- /// Initialiser from a set of points on an Eta-Phi plane, where
- /// eta can have an arbitrary ranges and phi must be in range
- /// 0 <= phi < 2pi;
- ///
- /// NB: this class is more efficient than the plain Dnn4piCylinder
- /// class, but can give wrong answers when the nearest neighbour is
- /// further away than 2pi (in this case a point's nearest neighbour
- /// becomes itself, because it is considered to be a distance 2pi
- /// away). For the kt-algorithm (e.g.) this is actually not a
- /// problem (the distance need only be accurate when it is less than
- /// R), so we can tell the routine to ignore this problem --
- /// alternatively the routine will crash if it detects it occurring
- /// (only when finding the nearest neighbour index, not its
- /// distance).
- Dnn2piCylinder(const std::vector<EtaPhi> &,
- const bool & ignore_nearest_is_mirror = false,
- const bool & verbose = false );
-
- /// Returns the index of the nearest neighbour of point labelled
- /// by ii (assumes ii is valid)
- int NearestNeighbourIndex(const int & ii) const ;
-
- /// Returns the distance to the nearest neighbour of point labelled
- /// by index ii (assumes ii is valid)
- double NearestNeighbourDistance(const int & ii) const ;
-
- /// Returns true iff the given index corresponds to a point that
- /// exists in the DNN structure (meaning that it has been added, and
- /// not removed in the meantime)
- bool Valid(const int & index) const;
-
- void RemoveAndAddPoints(const std::vector<int> & indices_to_remove,
- const std::vector<EtaPhi> & points_to_add,
- std::vector<int> & indices_added,
- std::vector<int> & indices_of_updated_neighbours);
-
- ~Dnn2piCylinder();
-
- private:
-
- // our extras to help us navigate, find distance, etc.
- const static int INEXISTENT_VERTEX=-3;
-
- bool _verbose;
-
- bool _ignore_nearest_is_mirror;
-
- /// Picture of how things will work... Copy 0--pi part of the 0--2pi
- /// cylinder into a region 2pi--2pi+ a bit of a Euclidean plane. Below we
- /// show points labelled by + that have a mirror image in this
- /// manner, while points labelled by * do not have a mirror image.
- ///
- /// | . |
- /// | . |
- /// | . |
- /// | . |
- /// | 2 . |
- /// | * . |
- /// | + . + |
- /// | 0 . 1 |
- /// | . |
- /// 0 2pi 2pi + a bit
- ///
- /// Each "true" point has its true "cylinder" index (the index that
- /// is known externally to this class) as well as euclidean plane
- /// indices (main_index and mirror index in the MirrorVertexInfo
- /// structure), which are private concepts of this class.
- ///
- /// In above picture our structures would hold the following info
- /// (the picture shows the euclidean-plane numbering)
- ///
- /// _mirror_info[cylinder_index = 0] = (0, 1)
- /// _mirror_info[cylinder_index = 1] = (2, INEXISTENT_VERTEX)
- ///
- /// We also need to be able to go from the euclidean plane indices
- /// back to the "true" cylinder index, and for this purpose we use
- /// the std::vector _cylinder_index_of_plane_vertex[...], which in the above example has
- /// the following contents
- ///
- /// _cylinder_index_of_plane_vertex[0] = 0
- /// _cylinder_index_of_plane_vertex[1] = 0
- /// _cylinder_index_of_plane_vertex[2] = 1
- ///
-
- ///
- struct MirrorVertexInfo {
- /// index of the given point (appearing in the range 0--2pi) in the
- /// 0--2pi euclidean plane structure (position will coincide with
- /// that on the 0--2pi cylinder, but index labelling it will be
- /// different)
- int main_index;
- /// index of the mirror point (appearing in the range 2pi--3pi) in the
- /// 0--3pi euclidean plane structure
- int mirror_index;
- };
-
- // for each "true" vertex we have reference to indices in the euclidean
- // plane structure
- std::vector<MirrorVertexInfo> _mirror_info;
- // for each index in the euclidean 0--2pi plane structure we want to
- // be able to get back to the "true" vertex index on the overall
- // 0--2pi cylinder structure
- std::vector<int> _cylinder_index_of_plane_vertex;
-
- // NB: we define POINTERS here because the initialisation gave
- // us problems (things crashed!), perhaps because in practice
- // we were making a copy without being careful and defining
- // a proper copy constructor.
- DnnPlane * _DNN;
-
- /// given a phi value in the 0--pi range return one
- /// in the 2pi--3pi range; whereas if it is in the pi-2pi range then
- /// remap it to be inthe range (-pi)--0.
- inline EtaPhi _remap_phi(const EtaPhi & point) {
- double phi = point.second;
- if (phi < pi) { phi += twopi ;} else {phi -= twopi;}
- return EtaPhi(point.first, phi);}
-
-
- //----------------------------------------------------------------------
- /// Actions here are similar to those in the
- /// Dnn3piCylinder::_RegisterCylinderPoint case, however here we do
- /// NOT create the mirror point -- instead we initialise the structure
- /// as if there were no need for the mirror point.
- ///
- /// ADDITIONALLY push the cylinder_point onto the vector plane_points.
- void _RegisterCylinderPoint (const EtaPhi & cylinder_point,
- std::vector<EtaPhi> & plane_points);
-
- /// For each plane point specified in the vector plane_indices,
- /// establish whether there is a need to create a mirror point
- /// according to the following criteria:
- ///
- /// . phi < pi
- /// . mirror does not already exist
- /// . phi < NearestNeighbourDistance
- /// (if this is not true then there is no way that its mirror point
- /// could have a nearer neighbour).
- ///
- /// If conditions all hold, then create the mirror point, insert it
- /// into the _DNN structure, adjusting any nearest neighbours, and
- /// return the list of plane points whose nearest neighbours have
- /// changed (this will include the new neighbours that have just been
- /// added)
- void _CreateNecessaryMirrorPoints(
- const std::vector<int> & plane_indices,
- std::vector<int> & updated_plane_points);
-
-};
-
-
-// here follow some inline implementations of the simpler of the
-// functions defined above
-
-//----------------------------------------------------------------------
-/// Note: one of the difficulties of the 0--2pi mapping is that
-/// a point may have its mirror copy as its own nearest neighbour
-/// (if no other point is within a distance of 2pi). This does
-/// not matter for the kt_algorithm with
-/// reasonable values of radius, but might matter for a general use
-/// of this algorithm -- depending on whether or not the user has
-/// initialised the class with instructions to ignore this problem the
-/// program will detect and ignore it, or crash.
-inline int Dnn2piCylinder::NearestNeighbourIndex(const int & current) const {
- int main_index = _mirror_info[current].main_index;
- int mirror_index = _mirror_info[current].mirror_index;
- int plane_index;
- if (mirror_index == INEXISTENT_VERTEX ) {
- plane_index = _DNN->NearestNeighbourIndex(main_index);
- } else {
- plane_index = (
- _DNN->NearestNeighbourDistance(main_index) <
- _DNN->NearestNeighbourDistance(mirror_index)) ?
- _DNN->NearestNeighbourIndex(main_index) :
- _DNN->NearestNeighbourIndex(mirror_index) ;
- }
- int this_cylinder_index = _cylinder_index_of_plane_vertex[plane_index];
- // either the user has acknowledged the fact that they may get the
- // mirror copy as the closest point, or crash if it should occur
- // that mirror copy is the closest point.
- assert(_ignore_nearest_is_mirror || this_cylinder_index != current);
- //if (this_cylinder_index == current) {
- // cerr << "WARNING point "<<current<<
- // " has its mirror copy as its own nearest neighbour"<<endl;
- //}
- return this_cylinder_index;
-}
-
-inline double Dnn2piCylinder::NearestNeighbourDistance(const int & current) const {
- int main_index = _mirror_info[current].main_index;
- int mirror_index = _mirror_info[current].mirror_index;
- if (mirror_index == INEXISTENT_VERTEX ) {
- return _DNN->NearestNeighbourDistance(main_index);
- } else {
- return (
- _DNN->NearestNeighbourDistance(main_index) <
- _DNN->NearestNeighbourDistance(mirror_index)) ?
- _DNN->NearestNeighbourDistance(main_index) :
- _DNN->NearestNeighbourDistance(mirror_index) ;
- }
-
-}
-
-inline bool Dnn2piCylinder::Valid(const int & index) const {
- return (_DNN->Valid(_mirror_info[index].main_index));
-}
-
-
-inline Dnn2piCylinder::~Dnn2piCylinder() {
- delete _DNN;
-}
-
-
-} // fastjet namespace
-
-#endif // __FASTJET_DNN2PICYLINDER_HH__
-#endif //DROP_CGAL
git://git.uio.no / u / mrichter / AliRoot.git / blobdiff