.. _program_listing_file__tmp_ws_src_ecl_core_ecl_statistics_include_ecl_statistics_cumulative_statistics.hpp:

Program Listing for File cumulative_statistics.hpp
==================================================

|exhale_lsh| :ref:`Return to documentation for file <file__tmp_ws_src_ecl_core_ecl_statistics_include_ecl_statistics_cumulative_statistics.hpp>` (``/tmp/ws/src/ecl_core/ecl_statistics/include/ecl/statistics/cumulative_statistics.hpp``)

.. |exhale_lsh| unicode:: U+021B0 .. UPWARDS ARROW WITH TIP LEFTWARDS

.. code-block:: cpp

   
   /*****************************************************************************
   ** Ifdefs
   *****************************************************************************/
   
   #ifndef ecl_statistics_CUMULATIVE_STATISTICS_HPP_
   #define ecl_statistics_CUMULATIVE_STATISTICS_HPP_
   
   /*****************************************************************************
   ** Includes
   *****************************************************************************/
   
   #include <ecl/mpl.hpp>
   #include <ecl/type_traits.hpp>
   
   /*****************************************************************************
   ** Namespaces
   *****************************************************************************/
   
   namespace ecl {
   
   /*****************************************************************************
   ** Interfaces
   *****************************************************************************/
   
   template <typename T, typename Enable = void>
   class CumulativeStatistics : public ecl::FailedObject {};
   
   template <typename T>
   class CumulativeStatistics<T, typename ecl::enable_if< ecl::is_float<T> >::type> {
   public:
     CumulativeStatistics(): number_of_data(0.0) {}
   
     void clear() { number_of_data = 0.0; }
   
     void push_back(const T & x)
     {
       number_of_data++;
       if(number_of_data == 1.0)
       {
         old_mean = new_mean = x;
         old_variance = 0.0;
       }
       else
       {
         new_mean = old_mean + static_cast<T>(x - old_mean) / static_cast<T>(number_of_data);
         new_variance = old_variance + static_cast<T>(x - old_mean) * static_cast<T>(x - new_mean);
   
         old_mean = new_mean;
         old_variance = new_variance;
       }
     }
   
     T size() const { return static_cast<T>(number_of_data); }
   
     T mean() const { return (number_of_data > 0) ? new_mean : 0.0; }
   
     T variance() const { return ((number_of_data > 1) ? new_variance / (number_of_data - 1) : 0.0); }
   
   private:
     T number_of_data;
     T old_mean, old_variance;
     T new_mean, new_variance;
   };
   
   /*****************************************************************************
   ** Trailers
   *****************************************************************************/
   
   } // namespace ecl
   
   #endif /* ecl_statistics_CUMULATIVE_STATISTICS_HPP_ */