PUtils.h

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// Author: M.A. Kagarlis
// Written: 15.12.98
// Revised: 17.10.00 by R. Holzmann
// Utilities Class Header
 
#ifndef _PUTILS_H_
#define _PUTILS_H_
 
#include "TRandom3.h"
#include "TMath.h"
using namespace std;
#include <iostream>
#include <cstdlib>
#include "TH1.h"
#include "PKinematics.h"
#include "PStaticData.h"
 
 
//#define SEED 65539
// set to 0 for random initialization of seed at startup
// (this initializes TRandom3 with systime (but only a
// granularity of 1 second)
 
//This is the new default (IF 20.09.2009)
#define SEED 0
 
#define PLUTOVERSION_FOR_FAIR 1
 
class PUtilsREngine;
PUtilsREngine &fPUtilsREngine();
PUtilsREngine *makePUtilsREngine();
 
 
class PUtilsREngine : public TObject {
 
 public:
    PUtilsREngine ();
 
    Double_t sampleFlat() {
    // Samples uniformly between 0 and 1
    return rnd->Rndm();
    }
 
    Double_t sampleGaus(Double_t c, Double_t s) {
    // Samples from a Gaussian distribution
    return rnd->Gaus(c,s);
    }
 
    Int_t samplePoisson(Double_t mean) {
    // Samples from a Poisson distribution
    return rnd->Poisson(mean);
    }
 
    Int_t sampleBinomial(Int_t ntot, Float_t prob) {
    // Samples from a binomial distribution
    return rnd->Binomial(ntot,prob);
    }
 
    Double_t sampleBW(Double_t c, Double_t g) {
    // Samples from a Breit Wigner distribution
    if (g == 0.) return c;
    return (c+0.5*g*TMath::Tan((2.0*rnd->Rndm()-1.0)*TMath::Pi()*0.5));
    }
 
    void SetSeed(UInt_t s);
 
    Double_t lambda(double M, double m1, double m2) {
    return PKinematics::lambda(M, m1, m2);
    }
 
    Double_t pcms2(double M, double m1, double m2) {
    return PKinematics::pcms2(M, m1, m2);
    }
 
    Double_t pcms(double M, double m1, double m2) {
    // cm momentum for the decay of M to m1 and m2
    return PKinematics::pcms(M, m1, m2);
    }
 
 
 private:
 
    TRandom3 *rnd;
 
    ClassDef(PUtilsREngine, 0) //Pluto Utilities Class (random wrapper)
};
 
 
class PUtils : public TObject {
 
 public:
  PUtils() {
      cout << "seed: " << SEED << endl;
      SetSeed(SEED);
  }
  // create former behaviour
 
  static void dsort(Double_t *, int);
  // Sort in ascending order the first (int) entries of the array (Double_t *).
  // Adapted from Ref 1
 
  static void isort(int *i, int n) {
      // Sort in ascending order the first (int) entries of the array (int *).
 
      //BUGBUG: Quickersort is unstable
      //see example:
      //Int_t a[3]={8,9,9};
      //PUtils::isort(a,3);
 
      //workaround: add very small number
 
    Double_t x[n];
 
    for (int j=0; j<n; ++j)
    x[j] = ((Double_t)i[j]) + ((Double_t)j)*0.00001;
    dsort(x, n);
    for (int j=0; j<n; ++j)
    i[j] = (int)x[j];
  }
 
  static Double_t sampleFlat() {
    // Samples uniformly between 0 and 1
    return makePUtilsREngine()->sampleFlat();
  }
 
  static Double_t sampleGaus(Double_t c, Double_t s) {
    // Samples from a Gaussian distribution
    return makePUtilsREngine()->sampleGaus(c, s);
  }
 
  static int samplePoisson(Double_t mean) {
    // Samples from a Poisson distribution
    return makePUtilsREngine()->samplePoisson(mean);
  }
 
  static Int_t sampleBinomial(Int_t ntot, Float_t prob) {
      // Samples from a binomial distribution
    return makePUtilsREngine()->sampleBinomial(ntot, prob);
  }
 
  static Double_t sampleBW(Double_t c, Double_t g) {
      // Samples from a Breit Wigner distribution
      return makePUtilsREngine()->sampleBW(c, g);
  }
 
  static Double_t cgc(const int &, const int &, const int &,
              const int &, const int &);
  // Clebsch-Gordan coefficients (arguments are 2 x j or m)
 
  static Double_t s3j(const Double_t &, const Double_t &, const Double_t &,
              const Double_t &, const Double_t &, Double_t m3 = 0.);
  // 3j-symbol, related to Clebsch-Gordan coefficient
 
  static Double_t racah(const int &, const int &, const int &,
            const int &, const int &, const int &);
  // Racah coefficients (arguments are 2 x j or m)
 
  static Double_t s6j(const Double_t &, const Double_t &, const Double_t &,
              const Double_t &, const Double_t &, const Double_t &);
  // 6j-symbol, related to Racah coefficient
 
  static Int_t FindIndex(Int_t n, Double_t *a, Double_t r);
 
  static void SetSeed(UInt_t s) { makePUtilsREngine()->SetSeed(s); }
 
  static Bool_t Tokenize(const char *options, const char *delimiter, char **array, int *size);
  static void remove_spaces(char **partc);
  static Int_t remove_brackets(char **partc, char a, char b);
  static Bool_t ValidVariableName(const char *name, unsigned int len = 0);
  static Bool_t IsInt(const char *name);
  static char *NewString(const char *var) {
      char *newvar = new char[strlen(var)+1];
      sprintf(newvar, "%s", var);
      return newvar;
  };
 
  static void correct_histo(TH1 *histo);
  static void correct(TH1 *histo);
 
 private:
 
  static Double_t phasef(const int &n) { return 1.- 2.*(abs(n)%2); }
  // (-1)**n
 
  static Double_t j123(const int &, const int &, const int &);
  // used by racah
 
 
  ClassDef(PUtils, 0) //Pluto Utilities Class
};
 
 
 
#endif // _PUTILS_H_