cumulative_distribution.cu

#include <thrust/device_vector.h>
#include <thrust/transform.h>
#include <thrust/functional.h>
#include <thrust/iterator/counting_iterator.h>
#include <thrust/iterator/constant_iterator.h>
#include <cstdio>

template <class T>
struct scaling {
	const T _a;
	scaling(T a) : _a(a) { }
	__host__ __device__ T operator()(const T &x) const { return _a * x; }
};

void main()
{
   const int N = 20;

   double a = -(double)N;
   double b = 0.;

   double Dx = -1./(0.5*N*(N+1));

   thrust::device_vector<double> MatingProbability(N);
   thrust::device_vector<double> CumulativeProbability(N+1, 0.);

   thrust::transform(thrust::make_counting_iterator(a), thrust::make_counting_iterator(b), MatingProbability.begin(), scaling<double>(Dx));

   thrust::inclusive_scan(MatingProbability.begin(), MatingProbability.end(), CumulativeProbability.begin() + 1);

   for(int i=0; i<N+1; i++) 
   {
      double val = CumulativeProbability[i];
      printf("%d %3.15f\n", i, val);
   }

}