geom_2d.h

// -*- C++ -*-
// File: geom_2d.h                                                           //
// Description: header file for two-dimensional geometry tools               //
// This file is part of the SISCone project.                                 //
// For more details, see http://projects.hepforge.org/siscone                //
//                                                                           //
// Copyright (c) 2006 Gavin Salam and Gregory Soyez                          //
//                                                                           //
// This program 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.                                       //
//                                                                           //
// This program 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 this program; if not, write to the Free Software               //
// Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA //
//                                                                           //
// $Revision::                                                              $//
// $Date::                                                                  $//
 
#ifndef __GEOM_2D_H__
#define __GEOM_2D_H__
 
#include <iostream>
#include <math.h>
#include "defines.h"
 
#ifndef M_PI
#define M_PI 3.141592653589793238462643383279502884197
#endif
 
namespace siscone{
 
inline double phi_in_range(double phi) {
  if      (phi <= -M_PI) phi += twopi;
  else if (phi >   M_PI) phi -= twopi;
  return phi;
}
 
inline double dphi(double phi1, double phi2) {
  return phi_in_range(phi1-phi2);
}
 
 
inline double abs_dphi(double phi1, double phi2) {
  double delta = fabs(phi1-phi2);
  return delta > M_PI ? twopi-delta : delta;
}
 
inline double pow2(double x) {return x*x;}
 
 
class Ctwovect {
public:
  Ctwovect() : x(0.0), y(0.0) {}
 
  Ctwovect(double _x, double _y) : x(_x), y(_y) {}
 
  double x, y;
 
  inline double mod2() const {return pow2(x)+pow2(y);}
 
  inline double modulus() const {return sqrt(mod2());}
};
 
 
inline double dot_product(const Ctwovect & a, const Ctwovect & b) {
  return a.x*b.x + a.y*b.y;
}
 
 
inline double cross_product(const Ctwovect & a, const Ctwovect & b) {
  return a.x*b.y - a.y*b.x;
}
 
 
class Ceta_phi_range{
public:
  Ceta_phi_range();
 
  Ceta_phi_range(double c_eta, double c_phi, double R);
 
  Ceta_phi_range& operator = (const Ceta_phi_range &r);
 
  int add_particle(const double eta, const double phi);
 
  unsigned int eta_range;     
 
  unsigned int phi_range;     
 
  // extremal value for eta
  static double eta_min;  
  static double eta_max;  
 
private:
  inline unsigned int get_eta_cell(double eta){
    return (unsigned int) (1u << ((int) (32*((eta-eta_min)/(eta_max-eta_min)))));
  }
 
  inline unsigned int get_phi_cell(double phi){
    return (unsigned int) (1u << ((int) (32*phi/twopi+16)%32));
  }
};
 
bool is_range_overlap(const Ceta_phi_range &r1, const Ceta_phi_range &r2);
 
const Ceta_phi_range range_union(const Ceta_phi_range &r1, const Ceta_phi_range &r2);
 
}
 
#endif