SphinxExamples/src/Numerics/Optimizers/LevenbergMarquardtOptimization/Code.cxx

/*=========================================================================
 *
 *  Copyright NumFOCUS
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
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 *         http://www.apache.org/licenses/LICENSE-2.0.txt
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 *  distributed under the License is distributed on an "AS IS" BASIS,
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// Include the Levenberg-Marquardt optimizer and a custom cost function
#include "itkLevenbergMarquardtOptimizer.h"
#include "itkExampleCostFunction.h"
 
// Typedef the optimizer and cost function, for convenience
using OptimizerType = itk::LevenbergMarquardtOptimizer;
using CostType = itk::ExampleCostFunction;
 
int
main(int, char *[])
{
 
  // Instantiate the cost function and optimizer
  CostType::Pointer      cost = CostType::New();
  OptimizerType::Pointer optimizer = OptimizerType::New();
 
  optimizer->SetNumberOfIterations(100);
  optimizer->UseCostFunctionGradientOff();
  optimizer->SetCostFunction(cost.GetPointer());
 
  // This is the initial guess for the parameter values, which we set to one
  CostType::ParametersType p(cost->GetNumberOfParameters());
  p.Fill(1);
  optimizer->SetInitialPosition(p);
  optimizer->StartOptimization();
 
  // Print out some information about the optimization
  // The parameters come out to be near to, but not exactly [5.5, 0.5]
  std::cout << "Position: " << optimizer->GetCurrentPosition() << std::endl;
  std::cout << "Value: " << optimizer->GetValue() << std::endl;
 
  return EXIT_SUCCESS;
}