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ITK optimizers are generic classes, which can be used independently of registration. This example demonstrates use of the itk::AmoebaOptimizer class in optimizing a simple paraboloid function.

Contributed by: Davis Vigneault


// Include the Amoeba optimizer and a custom cost function
#include "itkAmoebaOptimizer.h"
#include "ExampleCostFunction.h"
// Typedef the optimizer and cost function, for convenience
typedef itk::AmoebaOptimizer       OptimizerType;
typedef itk::ExampleCostFunction2  CostType;
int main(int, char *[])
  // Instantiate the optimizer
  OptimizerType::Pointer optimizer = OptimizerType::New();
  // Set properties pertinent to convergence
  optimizer->SetMaximumNumberOfIterations( 100 );
  optimizer->SetParametersConvergenceTolerance( 0.01 );
  optimizer->SetFunctionConvergenceTolerance( 0.01 );
  // Instantiate the cost function
  // The cost function is a 2D paraboloid in the x-y plane
  // with the equation f(x,y) = (x+5)^2+(y-7)^2 + 5
  // and a global minimum at (x,y) = (-5, 7)
  CostType::Pointer cost = CostType::New();
  // Assign the cost function to the optimizer
  optimizer->SetCostFunction( cost.GetPointer() );
  // Set the initial parameters of the cost function
  OptimizerType::ParametersType initial(2);
  initial[0] = 123;
  initial[1] = -97.4;
  optimizer->SetInitialPosition( initial );
  // Begin the optimization!
  // Print out some information about the optimization
  std::cout << "Position: " << optimizer->GetCurrentPosition() << std::endl;
  std::cout << "Value: " << optimizer->GetValue() << std::endl;
  // As expected, the position is near to (-5, 7) and the value to 5
  // Position: [-5.003825599641884, 6.998563761340231]
  // Value: 5.00002
  return EXIT_SUCCESS;


#ifndef ExampleCostFunction_h
#define ExampleCostFunction_h
#include "itkSingleValuedCostFunction.h"
namespace itk
class ExampleCostFunction2 :
public SingleValuedCostFunction
  /** Standard class typedefs. */
  typedef ExampleCostFunction2      Self;
  typedef SingleValuedCostFunction  Superclass;
  typedef SmartPointer<Self>        Pointer;
  typedef SmartPointer<const Self>  ConstPointer;
  /** Method for creation through the object factory. */
  /** Run-time type information (and related methods). */
  itkTypeMacro(ExampleCostFunction2, SingleValuedCostfunction);
  unsigned int GetNumberOfParameters(void) const { return 2; } // itk::CostFunction
  MeasureType GetValue(const ParametersType & parameters) const {
    return pow(parameters[0]+5, 2)+pow(parameters[1]-7, 2)+5;
  void GetDerivative(const ParametersType &,
                     DerivativeType & derivative ) const {
    throw itk::ExceptionObject( __FILE__, __LINE__, "No derivative is available for this cost function.");
  ExampleCostFunction2(const Self &); //purposely not implemented
  void operator = (const Self &); //purposely not implemented
} // end namespace itk


cmake_minimum_required(VERSION 3.9.5)
find_package(ITK REQUIRED)
if (ITKVtkGlue_LOADED)
  find_package(VTK REQUIRED)
add_executable(AmoebaOptimization MACOSX_BUNDLE AmoebaOptimization.cxx)
  target_link_libraries(AmoebaOptimization ITKReview ${ITK_LIBRARIES})
  target_link_libraries(AmoebaOptimization ${ITK_LIBRARIES})
endif( "${ITK_VERSION_MAJOR}" LESS 4 )

Download and Build AmoebaOptimization

Click here to download AmoebaOptimization and its CMakeLists.txt file. Once the tarball AmoebaOptimization.tar has been downloaded and extracted,

cd AmoebaOptimization/build
  • If ITK is installed:
cmake ..
  • If ITK is not installed but compiled on your system, you will need to specify the path to your ITK build:
cmake -DITK_DIR:PATH=/home/me/itk_build ..

Build the project:


and run it:


WINDOWS USERS PLEASE NOTE: Be sure to add the ITK bin directory to your path. This will resolve the ITK dll's at run time.

Building All of the Examples

Many of the examples in the ITK Wiki Examples Collection require VTK. You can build all of the the examples by following these instructions. If you are a new VTK user, you may want to try the Superbuild which will build a proper ITK and VTK.


ITK >= 4

For examples that use QuickView (which depends on VTK), you must have built ITK with Module_ITKVtkGlue=ON.

ITK < 4

Some of the ITK Examples require VTK to display the images. If you download the entire ITK Wiki Examples Collection, the ItkVtkGlue directory will be included and configured. If you wish to just build a few examples, then you will need to download ItkVtkGlue and build it. When you run cmake it will ask you to specify the location of the ItkVtkGlue binary directory.