CostFuncRwp.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 +
//----------------------------------------------------------------------
// Includes
//----------------------------------------------------------------------
#include "MantidCurveFitting/CostFunctions/CostFuncRwp.h"
#include "MantidAPI/CompositeDomain.h"
#include "MantidAPI/FunctionValues.h"
#include "MantidAPI/IConstraint.h"
#include "MantidCurveFitting/SeqDomain.h"
 
#include <cmath>
 
namespace Mantid::CurveFitting::CostFunctions {
 
DECLARE_COSTFUNCTION(CostFuncRwp, Rwp)
 
//----------------------------------------------------------------------------------------------
CostFuncRwp::CostFuncRwp() : CostFuncLeastSquares() {
  m_includePenalty = false;
  m_value = 0.;
  m_pushed = false;
  m_factor = 1.;
}
 
std::vector<double> CostFuncRwp::getFitWeights(API::FunctionValues_sptr values) const {
  double sqrtW = calSqrtW(values);
 
  std::vector<double> weights(values->size());
  for (size_t i = 0; i < weights.size(); ++i) {
    weights[i] = getWeight(values, i, sqrtW);
  }
 
  return weights;
}
 
//----------------------------------------------------------------------------------------------
double CostFuncRwp::getWeight(const API::FunctionValues_sptr &values, size_t i, double sqrtW) const {
  return (values->getFitWeight(i) / sqrtW);
}
 
//----------------------------------------------------------------------------------------------
double CostFuncRwp::calSqrtW(const API::FunctionValues_sptr &values) const {
  double weight = 0.0;
 
  // FIXME : This might give a wrong answer in case of multiple-domain
  size_t ny = values->size();
  for (size_t i = 0; i < ny; ++i) {
    double obsval = values->getFitData(i);
    double inv_sigma = values->getFitWeight(i);
    weight += obsval * obsval * inv_sigma * inv_sigma;
  }
 
  return sqrt(weight);
}
 
} // namespace Mantid::CurveFitting::CostFunctions