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/*=========================================================================
Program: Insight Segmentation & Registration Toolkit
Module: $RCSfile: itkConjugateGradientOptimizer.cxx,v $
Language: C++
Date: $Date: 2007-03-22 14:29:13 $
Version: $Revision: 1.25 $
Copyright (c) Insight Software Consortium. All rights reserved.
See ITKCopyright.txt or http://www.itk.org/HTML/Copyright.htm for details.
This software is distributed WITHOUT ANY WARRANTY; without even
the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
PURPOSE. See the above copyright notices for more information.
=========================================================================*/
#ifndef _itkConjugateGradientOptimizer_txx
#define _itkConjugateGradientOptimizer_txx
#include "itkConjugateGradientOptimizer.h"
namespace itk
{
/**
* Constructor
*/
ConjugateGradientOptimizer
::ConjugateGradientOptimizer()
{
m_OptimizerInitialized = false;
m_VnlOptimizer = 0;
}
/**
* Destructor
*/
ConjugateGradientOptimizer
::~ConjugateGradientOptimizer()
{
delete m_VnlOptimizer;
}
/**
* Get the Optimizer
*/
vnl_conjugate_gradient *
ConjugateGradientOptimizer
::GetOptimizer( void )
{
return m_VnlOptimizer;
}
/**
* Connect a Cost Function
*/
void
ConjugateGradientOptimizer
::SetCostFunction( SingleValuedCostFunction * costFunction )
{
const unsigned int numberOfParameters =
costFunction->GetNumberOfParameters();
CostFunctionAdaptorType * adaptor =
new CostFunctionAdaptorType( numberOfParameters );
adaptor->SetCostFunction( costFunction );
if( m_OptimizerInitialized )
{
delete m_VnlOptimizer;
}
this->SetCostFunctionAdaptor( adaptor );
m_VnlOptimizer = new vnl_conjugate_gradient( *adaptor );
m_OptimizerInitialized = true;
}
/** Return Current Value */
ConjugateGradientOptimizer::MeasureType
ConjugateGradientOptimizer
::GetValue() const
{
ParametersType parameters = this->GetCurrentPosition();
if(m_ScalesInitialized)
{
const ScalesType scales = this->GetScales();
for(unsigned int i=0;i<parameters.size();i++)
{
parameters[i] *= scales[i];
}
}
return this->GetNonConstCostFunctionAdaptor()->f( parameters );
}
/**
* Start the optimization
*/
void
ConjugateGradientOptimizer
::StartOptimization( void )
{
this->InvokeEvent( StartEvent() );
if( this->GetMaximize() )
{
this->GetNonConstCostFunctionAdaptor()->NegateCostFunctionOn();
}
ParametersType initialPosition = this->GetInitialPosition();
ParametersType parameters(initialPosition);
// If the user provides the scales then we set otherwise we don't
// for computation speed.
// We also scale the initial parameters up if scales are defined.
// This compensates for later scaling them down in the cost function adaptor
// and at the end of this function.
if(m_ScalesInitialized)
{
ScalesType scales = this->GetScales();
this->GetNonConstCostFunctionAdaptor()->SetScales(scales);
for(unsigned int i=0;i<parameters.size();i++)
{
parameters[i] *= scales[i];
}
}
// vnl optimizers return the solution by reference
// in the variable provided as initial position
m_VnlOptimizer->minimize( parameters );
// we scale the parameters down if scales are defined
if(m_ScalesInitialized)
{
ScalesType scales = this->GetScales();
for(unsigned int i=0;i<parameters.size();i++)
{
parameters[i] /= scales[i];
}
}
this->SetCurrentPosition( parameters );
this->InvokeEvent( EndEvent() );
}
/**
* Get the maximum number of evaluations of the function.
* In vnl this is used instead of a maximum number of iterations
* given that an iteration could imply several evaluations.
*/
unsigned long
ConjugateGradientOptimizer
::GetNumberOfIterations( void ) const
{
return m_VnlOptimizer->get_max_function_evals();
}
/**
* Get the number of iterations in the last optimization.
*/
unsigned long
ConjugateGradientOptimizer
::GetCurrentIteration( void ) const
{
return m_VnlOptimizer->get_num_iterations();
}
} // end namespace itk
#endif
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