AvgDiagKernelNormalizer.h

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00001 /*
00002  * This program is free software; you can redistribute it and/or modify
00003  * it under the terms of the GNU General Public License as published by
00004  * the Free Software Foundation; either version 3 of the License, or
00005  * (at your option) any later version.
00006  *
00007  * Written (W) 2009 Soeren Sonnenburg
00008  * Copyright (C) 2009 Fraunhofer Institute FIRST and Max-Planck-Society
00009  */
00010 
00011 #ifndef _AVGDIAGKERNELNORMALIZER_H___
00012 #define _AVGDIAGKERNELNORMALIZER_H___
00013 
00014 #include "kernel/KernelNormalizer.h"
00015 namespace shogun
00016 {
00031 class CAvgDiagKernelNormalizer : public CKernelNormalizer
00032 {
00033     public:
00039         CAvgDiagKernelNormalizer(float64_t c=0.0)
00040         {
00041             scale=c;
00042         }
00043 
00045         virtual ~CAvgDiagKernelNormalizer()
00046         {
00047         }
00048 
00051         virtual bool init(CKernel* k)
00052         {
00053             if (scale<=0)
00054             {
00055                 ASSERT(k);
00056                 int32_t num=k->get_num_vec_lhs();
00057                 ASSERT(num>0);
00058 
00059                 CFeatures* old_lhs=k->lhs;
00060                 CFeatures* old_rhs=k->rhs;
00061                 k->lhs=old_lhs;
00062                 k->rhs=old_lhs;
00063 
00064                 float64_t sum=0;
00065                 for (int32_t i=0; i<num; i++)
00066                     sum+=k->compute(i, i);
00067 
00068                 scale=sum/num;
00069                 k->lhs=old_lhs;
00070                 k->rhs=old_rhs;
00071             }
00072 
00073             return true;
00074         }
00075 
00081         inline virtual float64_t normalize(
00082             float64_t value, int32_t idx_lhs, int32_t idx_rhs)
00083         {
00084             return value/scale;
00085         }
00086 
00091         inline virtual float64_t normalize_lhs(float64_t value, int32_t idx_lhs)
00092         {
00093             return value/sqrt(scale);
00094         }
00095 
00100         inline virtual float64_t normalize_rhs(float64_t value, int32_t idx_rhs)
00101         {
00102             return value/sqrt(scale);
00103         }
00104 
00106         inline virtual const char* get_name() const { return "AvgDiagKernelNormalizer"; }
00107 
00108     protected:
00110         float64_t scale;
00111 };
00112 }
00113 #endif

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