UnuRanDist.h

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// class to test unuran dist

#include "TUnuran.h"
#include "Math/Util.h"

#include <iostream> 
#include <cassert> 

class UnuRanDist { 
public:


   UnuRanDist() : first(true) {
      // use default grandom
   }
   

      //~UnuRanDist() { if (fUnuran) delete fUnuran; }                                               

   void SetSeed(int seed) {
      gRandom->SetSeed(seed);
      first = true; 
   }
   
   double Gaus(double mu, double sigma) {
      if (first) { 
         //if (!fUnuran.Init("normal()", "method=cstd;variant=0") ) { // acr method (default)
         if (!fUnuran.Init("normal()", "method=cstd;variant=6") ) {
            assert(0);
         }
         first = false;
      }
      return mu + sigma* fUnuran.Sample();
   }

   int Poisson(double mu) { 
      if (first) { 
//          std::string smu = ROOT::Math::Util::ToString(mu);
//          std::string dist = "poisson(" + smu + ")";
//          if (!fUnuran.Init(dist, "method=dstd") ) {
//             assert(0);
//          }
          if (!fUnuran.InitPoisson(mu,"method=dstd") ) {
             assert(0);
          }
         
         first = false;
      }
      else { 
         par[0] = mu; 
         fUnuran.ReInitDiscrDist(1,par);
      }
      return fUnuran.SampleDiscr();
   }

   int Binomial(int n, double p) { 
      if (first) { 
//          std::string sn = ROOT::Math::Util::ToString(n);
//          std::string sp = ROOT::Math::Util::ToString(p);
//          std::string dist = "binomial(" + sn + "," + sp + ")";
//          std::cout << dist << std::endl;
         if (!fUnuran.InitBinomial(n,p,"method=dstd") ) {
             assert(0);
          }
         first = false;
      }
      else { 
         par[0] = n; 
         par[1] = p; 
         fUnuran.ReInitDiscrDist(2,par);
      }
      return fUnuran.SampleDiscr();
   }



private:
   TUnuran fUnuran; 
   bool  first;
   double par[2]; 
};

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