MostLikelyMean.cpp

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// Mantid Repository : https://github.com/mantidproject/mantid
//
// Copyright © 2018 ISIS Rutherford Appleton Laboratory UKRI,
//   NScD Oak Ridge National Laboratory, European Spallation Source,
//   Institut Laue - Langevin & CSNS, Institute of High Energy Physics, CAS
// SPDX - License - Identifier: GPL - 3.0 +
#include "MantidAlgorithms/MostLikelyMean.h"
#include "MantidKernel/ArrayLengthValidator.h"
#include "MantidKernel/ArrayProperty.h"
#include "MantidKernel/MultiThreaded.h"
#include "MantidKernel/PropertyWithValue.h"
 
#include "boost/multi_array.hpp"
 
namespace Mantid::Algorithms {
 
using Mantid::Kernel::ArrayLengthValidator;
using Mantid::Kernel::ArrayProperty;
using Mantid::Kernel::Direction;
using Mantid::Kernel::PropertyWithValue;
 
// Register the algorithm into the AlgorithmFactory
DECLARE_ALGORITHM(MostLikelyMean)
 
//----------------------------------------------------------------------------------------------
 
 
const std::string MostLikelyMean::name() const { return "MostLikelyMean"; }
 
int MostLikelyMean::version() const { return 1; }
 
const std::string MostLikelyMean::category() const { return "Arithmetic"; }
 
const std::string MostLikelyMean::summary() const {
  return "Computes the most likely mean of the array by minimizing the taxicab "
         "distance of the elements from the rest.";
}
 
//----------------------------------------------------------------------------------------------
void MostLikelyMean::init() {
  auto lengthValidator = std::make_shared<ArrayLengthValidator<double>>();
  lengthValidator->setLengthMin(1);
  declareProperty(std::make_unique<ArrayProperty<double>>("InputArray", lengthValidator, Direction::Input),
                  "An input array.");
  declareProperty(std::make_unique<PropertyWithValue<double>>("Output", 0., Direction::Output), "The output (mean).");
}
 
//----------------------------------------------------------------------------------------------
void MostLikelyMean::exec() {
  const std::vector<double> input = getProperty("InputArray");
  const auto size = static_cast<int>(input.size());
  boost::multi_array<double, 2> cov(boost::extents[size][size]);
  PARALLEL_FOR_NO_WSP_CHECK()
  for (int i = 0; i < size; ++i) {
    for (int j = 0; j <= i; ++j) {
      double diff = sqrt(fabs(input[i] - input[j]));
      cov[i][j] = diff;
      cov[j][i] = diff;
    }
  }
  std::vector<double> sums(size);
  for (int i = 0; i < size; ++i) {
    sums[i] = std::accumulate(cov[i].begin(), cov[i].end(), 0.);
  }
  const auto minIndex = std::min_element(sums.cbegin(), sums.cend());
  setProperty("Output", input[std::distance(sums.cbegin(), minIndex)]);
}
 
} // namespace Mantid::Algorithms