source: trunk/lib/statistics/utility.cc @ 298

// $Id: utility.cc 298 2005-04-29 12:16:21Z peter $


#include <c++_tools/statistics/utility.h>

#include <vector>
#include <algorithm>

#include <cmath>
#include <cstdlib>
#include <gsl/gsl_randist.h>
#include <iostream>


namespace theplu {
namespace statistics {  

  double cdf_hypergeometric_P(u_int k, u_int n1, u_int n2, u_int t)
  {
    double p=0;
    for (u_int i=0; i<=k; i++)
      p+= gsl_ran_hypergeometric_pdf(i, n1, n2, t);
    return p;
  }


  double median(std::vector<double>& vec) 
  {
    return percentile(vec, 50.0);
  }

  double median(std::vector<size_t>& vec) 
  {
    return percentile(vec, 50.0);
  }

  double percentile(std::vector<double>& vec, double percentile) 
  {
    if (percentile==100)
      return  vec[vec.size()-1];
    else{
      sort(vec.begin(), vec.end());
      double j = percentile/100 * (vec.size()-1);
      int i = static_cast<int>(j);
      return (1-j+floor(j))*vec[i] + (j-floor(j))*vec[i+1];
    }
  }

  double percentile(std::vector<size_t>& vec, double percentile) 
  {
    if (percentile==100)
      return vec[vec.size()-1];
    else{
      sort(vec.begin(), vec.end());
      double j = percentile/100 * (vec.size()-1);
      int i = static_cast<int>(j);
      return (1-j+floor(j))*vec[i] + (j-floor(j))*vec[i+1];
    }
    
  }


}} // of namespace statistics and namespace theplu