FBDTClassifierHelper.h

/**************************************************************************
 * basf2 (Belle II Analysis Software Framework)                           *
 * Author: The Belle II Collaboration                                     *
 *                                                                        *
 * See git log for contributors and copyright holders.                    *
 * This file is licensed under LGPL-3.0, see LICENSE.md.                  *
 **************************************************************************/
 
#pragma once
 
#include <framework/logging/Logger.h>
 
#include <vector>
#include <iostream>
#include <string>
#include <array>
 
namespace Belle2 {
  template<size_t Ndims = 9>
  struct FBDTTrainSample {
    explicit FBDTTrainSample(const std::array<double, Ndims>& values, bool sig) : hits(values), signal(sig) {}
 
    FBDTTrainSample() { };
 
    std::array<double, Ndims> hits{};
 
    bool signal{};
  };
 
  template<size_t Ndims>
  static void readSamplesFromStream(std::istream& is, std::vector<FBDTTrainSample<Ndims> >& samples)
  {
    size_t nSamplesBefore = samples.size();
    std::string line;
    while (!is.eof()) {
      getline(is, line);
      if (line.empty()) continue; // ignore empty lines
      std::stringstream ss(line);
      std::array<double, 9> coords;
      for (double& c : coords) ss >> c;
      bool sig; ss >> sig;
 
      samples.push_back(FBDTTrainSample<9>(coords, sig));
    }
 
    B2INFO("Read in " << (samples.size() - nSamplesBefore) << " samples.");
  }
 
  template<size_t Ndims>
  static void writeSamplesToStream(std::ostream& os, const std::vector<FBDTTrainSample<Ndims> >& samples)
  {
    for (const auto& event : samples) {
      for (const auto& val : event.hits) {
        os << val << " ";
      }
      os << event.signal << std::endl;
    }
    B2INFO("Wrote out " << samples.size() << " samples.");
  }
}