source: trunk/lib/statistics/utility.cc @ 511

// $Id: utility.cc 511 2006-02-18 14:46:46Z peter $


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

#include <gsl/gsl_randist.h>
#include <gsl/gsl_statistics_double.h>

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(const gslapi::vector& vec, const bool sorted)
  {
    if (!sorted){
      gslapi::vector vec_copy(vec);
      vec_copy.sort();
      return gsl_stats_median_from_sorted_data (vec_copy.gsl_vector_p()->data, 
                                                vec_copy.gsl_vector_p()->stride,
                                                vec_copy.gsl_vector_p()->size);
    }
    return gsl_stats_median_from_sorted_data (vec.gsl_vector_p()->data, 
                                              vec.gsl_vector_p()->stride,
                                              vec.gsl_vector_p()->size);
  }

  double percentile(const gslapi::vector& vec, const double p, 
                    const bool sorted)
  {
    if (!sorted){
      gslapi::vector vec_c(vec);
      vec_c.sort();
      return gsl_stats_quantile_from_sorted_data(vec_c.gsl_vector_p()->data,
                                                 vec_c.gsl_vector_p()->stride,
                                                 vec_c.gsl_vector_p()->size,
                                                 p);
    }
    return gsl_stats_quantile_from_sorted_data (vec.gsl_vector_p()->data, 
                                              vec.gsl_vector_p()->stride,
                                              vec.gsl_vector_p()->size,
                                              p);
  }

}} // of namespace statistics and namespace theplu