itkMultivariateLegendrePolynomial.h

Go to the documentation of this file.

/*=========================================================================

Program:   Insight Segmentation & Registration Toolkit
Module:    $RCSfile: itkMultivariateLegendrePolynomial.h,v $
Language:  C++
Date:      $Date: 2002/07/30 13:53:04 $
Version:   $Revision: 1.15 $

Copyright (c) 2002 Insight 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 __itkMultivariateLegendrePolynomial_h
#define __itkMultivariateLegendrePolynomial_h

#include "itkArray.h"

namespace itk {

class MultivariateLegendrePolynomial
{
public:
  //   /** Legendre polynomial coefficients type. */
  //   typedef Array<double>             CoefficientVectorType;

  typedef Array< double > DoubleArrayType ;
  typedef Array< unsigned long > ULongArrayType ;
  typedef Array< long > LongArrayType ;

  typedef DoubleArrayType CoefficientArrayType ;

  typedef DoubleArrayType ParametersType ;

  typedef ULongArrayType DomainSizeType ;
  typedef LongArrayType IndexType ;
  
  MultivariateLegendrePolynomial( unsigned int dimension, 
                                  unsigned int degree,
                                  const DomainSizeType & domainSize );
  virtual ~MultivariateLegendrePolynomial();

  void Initialize(void) ;

  unsigned int GetDimension(void) const 
  { return m_Dimension ; }

  unsigned int GetDegree(void) const 
  { return m_Degree ; } 

  unsigned int GetNumberOfCoefficients(void) const
  { return m_NumberOfCoefficients; }

  const DomainSizeType & GetDomainSize( void ) const 
  { return m_DomainSize; }

  class CoefficientVectorSizeMismatch 
  {
  public:
    CoefficientVectorSizeMismatch(int given, int required)
    {
      Required = required ;
      Given = given ;
    }
    
    int Required;
    int Given ;
  } ;

  void SetCoefficients(const CoefficientArrayType & coef) 
    throw (CoefficientVectorSizeMismatch) ;

  const CoefficientArrayType* GetCoefficients(void) const;
 
  double operator() (IndexType index) 
  {
    if (m_Dimension == 2)
      {
        if (index[1] != m_PrevY)
          {
            // normalized y [-1, 1]
            double norm_y =  (*m_NormFactor)[1] *
              static_cast<double>( index[1] - 1 );
            CalculateXCoef(norm_y, m_CoefficientArray) ;
            m_PrevY = index[1] ;
          }
        
        // normalized x [-1, 1]
        double norm_x =  (*m_NormFactor)[0] *
          static_cast<double>( index[0] - 1 );
        
        return LegendreSum(norm_x, m_Degree, m_CachedXCoef) ;
      }
    else if (m_Dimension == 3)
      {
        if (m_PrevZ != index[2])
          {
            // normalized z [-1, 1]  
            double norm_z =  (*m_NormFactor)[2] *
              static_cast<double>( index[2] - 1 );
            CalculateYCoef(norm_z, m_CoefficientArray) ;
            m_PrevZ = index[2] ;
          }
        
        if (m_PrevY != index[1])
          {
            // normalized y [-1, 1]
            double norm_y =  (*m_NormFactor)[1] *
              static_cast<double>( index[1] - 1 ); 
            CalculateXCoef(norm_y, m_CachedYCoef) ;
            m_PrevY = index[1] ;
          }
        
        // normalized x [-1, 1]
        double norm_x =  (*m_NormFactor)[0] *
          static_cast<double>( index[0] - 1 ); 
        return LegendreSum(norm_x, m_Degree, m_CachedXCoef) ;
      }
    return 0 ;
  }

  unsigned int GetNumberOfCoefficients(void);

  unsigned int GetNumberOfCoefficients(unsigned int dimension, unsigned int degree) ;

  class SimpleForwardIterator
  {
  public:
    SimpleForwardIterator (MultivariateLegendrePolynomial* polynomial) 
    {
      m_MultivariateLegendrePolynomial = polynomial ;
      m_Dimension   = m_MultivariateLegendrePolynomial->GetDimension();
      m_DomainSize  = m_MultivariateLegendrePolynomial->GetDomainSize();
      m_Index       = IndexType(m_Dimension);
    }
    
    void Begin( void ) 
    { 
      m_Index.Fill( 0 ) ;
      m_IsAtEnd = false ;
    }
    
    bool IsAtEnd()
    { return m_IsAtEnd; }
    
    SimpleForwardIterator& operator++()
    {
      for (unsigned int dim = 0 ; dim < m_Dimension ; dim++)
        {
          if (m_Index[dim] < static_cast<int>(m_DomainSize[dim] - 1))
            {
              m_Index[dim] += 1 ;
              return *this ;
            }
          else
            {
              if (dim == m_Dimension - 1 )
                {
                  m_IsAtEnd = true ;
                  break ;
                }
              else
                {
                  m_Index[dim] = 0 ;
                }
            }
        }
      return *this ;
    }
    
    double Get()
    { return (*m_MultivariateLegendrePolynomial)(m_Index); }
    
  private:
    MultivariateLegendrePolynomial* m_MultivariateLegendrePolynomial;
    unsigned int      m_Dimension; 
    DomainSizeType    m_DomainSize;
    IndexType         m_Index;
    bool              m_IsAtEnd;
  } ; // end of class Iterator 
  
protected:
  double LegendreSum(const double x, int n, const CoefficientArrayType* coef,
                     int offset = 0); 
  void CalculateXCoef(double norm_y, const CoefficientArrayType* coef);
  void CalculateYCoef(double norm_z, const CoefficientArrayType* coef);

private:
  DomainSizeType m_DomainSize;
  unsigned int m_Dimension;
  unsigned int m_Degree;
  unsigned int m_NumberOfCoefficients;
  bool m_MultiplicativeBias; 
  
  //   CoefficientVectorType   m_CoefficientVector;
  CoefficientArrayType* m_CoefficientArray;
  CoefficientArrayType* m_CachedXCoef;
  CoefficientArrayType* m_CachedYCoef;
  CoefficientArrayType* m_CachedZCoef;
  DoubleArrayType* m_NormFactor;
  long m_PrevY ;
  long m_PrevZ ;
} ; // end of class

} // end of namespace itk
#endif

---