cmtkIterativeDirectionOptimizer.cxx

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/*
//
//  Copyright 1997-2009 Torsten Rohlfing
//
//  Copyright 2004-2010 SRI International
//
//  This file is part of the Computational Morphometry Toolkit.
//
//  http://www.nitrc.org/projects/cmtk/
//
//  The Computational Morphometry Toolkit is free software: you can
//  redistribute it and/or modify it under the terms of the GNU General Public
//  License as published by the Free Software Foundation, either version 3 of
//  the License, or (at your option) any later version.
//
//  The Computational Morphometry Toolkit is distributed in the hope that it
//  will be useful, but WITHOUT ANY WARRANTY; without even the implied
//  warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//  GNU General Public License for more details.
//
//  You should have received a copy of the GNU General Public License along
//  with the Computational Morphometry Toolkit.  If not, see
//  <http://www.gnu.org/licenses/>.
//
//  $Revision: 2398 $
//
//  $LastChangedDate: 2010-10-05 14:54:37 -0700 (Tue, 05 Oct 2010) $
//
//  $LastChangedBy: torstenrohlfing $
//
*/

#include "cmtkIterativeDirectionOptimizer.h"

#include <System/cmtkProgress.h>

#include <vector>

namespace
cmtk
{


CallbackResult 
IterativeDirectionOptimizer::Optimize
( CoordinateVector& v, const Types::Coordinate exploration, const Types::Coordinate accuracy )
{
  int Dim = this->GetSearchSpaceDimension();

  Types::Coordinate optimum = this->Evaluate( v );
  CoordinateVector optimumV(v);

  const double real_accuracy = std::min<Types::Coordinate>( exploration, accuracy );
  int numOfSteps = 1+static_cast<int>(log(real_accuracy/exploration)/log(StepFactor));
  Types::Coordinate step = real_accuracy * pow( StepFactor, 1-numOfSteps );

  std::vector<Types::Coordinate> stepScaleVector( Dim );
  for ( int idx=0; idx<Dim; ++idx )
    stepScaleVector[idx] = this->GetParamStep( idx );

  Progress::Begin( 0, numOfSteps, 1, "Multi-resolution optimization" );

  CallbackResult irq = this->CallbackExecuteWithData( v, optimum );
  for ( int stepIdx = 0; (stepIdx < numOfSteps) && ( irq == CALLBACK_OK ); ++stepIdx, step *= StepFactor ) 
    {
    Progress::SetProgress( stepIdx );

    char comment[128];
    snprintf( comment, sizeof( comment ), "Setting step size to %4g [mm]", step );
    this->CallbackComment( comment );

    bool update = true;
    while ( update && ( irq == CALLBACK_OK ) ) 
      {
      update = false;
      
      for ( int dim = 0; (dim < Dim) && ( irq == CALLBACK_OK ); ++dim ) 
        {
        bool updateThisDim = true;
        while ( updateThisDim && ( irq == CALLBACK_OK ) ) 
          {
          updateThisDim = false;
          
          Types::Coordinate vOld = v[dim];
          
          if ( (irq = this->CallbackExecute()) ) break;
          
          v[dim] += step * stepScaleVector[dim];
      const Self::ReturnType fUpper = this->Evaluate( v );
          
          Types::Coordinate optimumStep = 0;
          
          if ( fUpper > optimum ) 
            {
            optimum = fUpper;
            optimumV = v;
            updateThisDim = true;
            optimumStep = step;
            }
          
          if ( (irq = this->CallbackExecute()) ) break;
          
          v[dim] = vOld - (step * stepScaleVector[dim]);
      const Self::ReturnType fLower = this->Evaluate( v );
          
          if ( fLower > optimum ) 
            {
            optimum = fLower;
            optimumV = v;
            updateThisDim = true;
            optimumStep = -step;
            }
          
          if ( updateThisDim ) 
            {
            update = true;
            while ( updateThisDim ) 
              {
              updateThisDim = false;
              vOld = v[dim];
              v[dim] += optimumStep * stepScaleVector[dim];
          const Self::ReturnType f = this->Evaluate( v );
              
              if ( f > optimum ) 
                {
                optimum = f;
                optimumV = v;
                updateThisDim = true;
                }
              
              if ( (irq = this->CallbackExecute()) ) break;
              }
            updateThisDim = true;
            }
          
          v[dim] = vOld;
          }
        
        if ( update ) 
          {
          v = optimumV;
          irq = this->CallbackExecuteWithData( v, optimum );
          // query functional for new parameter steppings if the respective
          // optimzier flag is set.
          if ( this->m_UpdateStepScaleVector )
            for ( int idx=0; idx<Dim; ++idx )
              stepScaleVector[idx] = this->GetParamStep( idx );
          }
        }
      }
    }

  Progress::Done();
  
  return irq;
}

} // namespace cmtk