DiceKernelNormalizer.h
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00011 #ifndef _DICEKERNELNORMALIZER_H___
00012 #define _DICEKERNELNORMALIZER_H___
00013
00014 #include "kernel/KernelNormalizer.h"
00015 #include "kernel/CommWordStringKernel.h"
00016
00017 namespace shogun
00018 {
00026 class CDiceKernelNormalizer : public CKernelNormalizer
00027 {
00028 public:
00033 CDiceKernelNormalizer(bool use_opt_diag=false) : diag_lhs(NULL),
00034 diag_rhs(NULL), use_optimized_diagonal_computation(use_opt_diag)
00035 {
00036 }
00037
00039 virtual ~CDiceKernelNormalizer()
00040 {
00041 delete[] diag_lhs;
00042 delete[] diag_rhs;
00043 }
00044
00047 virtual bool init(CKernel* k)
00048 {
00049 ASSERT(k);
00050 int32_t num_lhs=k->get_num_vec_lhs();
00051 int32_t num_rhs=k->get_num_vec_rhs();
00052 ASSERT(num_lhs>0);
00053 ASSERT(num_rhs>0);
00054
00055 CFeatures* old_lhs=k->lhs;
00056 CFeatures* old_rhs=k->rhs;
00057
00058 k->lhs=old_lhs;
00059 k->rhs=old_lhs;
00060 bool r1=alloc_and_compute_diag(k, diag_lhs, num_lhs);
00061
00062 k->lhs=old_rhs;
00063 k->rhs=old_rhs;
00064 bool r2=alloc_and_compute_diag(k, diag_rhs, num_rhs);
00065
00066 k->lhs=old_lhs;
00067 k->rhs=old_rhs;
00068
00069 return r1 && r2;
00070 }
00071
00077 inline virtual float64_t normalize(
00078 float64_t value, int32_t idx_lhs, int32_t idx_rhs)
00079 {
00080 float64_t diag_sum=diag_lhs[idx_lhs]*diag_rhs[idx_rhs];
00081 return 2*value/diag_sum;
00082 }
00083
00088 inline virtual float64_t normalize_lhs(float64_t value, int32_t idx_lhs)
00089 {
00090 SG_ERROR("linadd not supported with Dice normalization.\n");
00091 return 0;
00092 }
00093
00098 inline virtual float64_t normalize_rhs(float64_t value, int32_t idx_rhs)
00099 {
00100 SG_ERROR("linadd not supported with Dice normalization.\n");
00101 return 0;
00102 }
00103
00104 public:
00109 bool alloc_and_compute_diag(CKernel* k, float64_t* &v, int32_t num)
00110 {
00111 delete[] v;
00112 v=new float64_t[num];
00113
00114 for (int32_t i=0; i<num; i++)
00115 {
00116 if (k->get_kernel_type() == K_COMMWORDSTRING)
00117 {
00118 if (use_optimized_diagonal_computation)
00119 v[i]=((CCommWordStringKernel*) k)->compute_diag(i);
00120 else
00121 v[i]=((CCommWordStringKernel*) k)->compute_helper(i,i, true);
00122 }
00123 else
00124 v[i]=k->compute(i,i);
00125
00126 if (v[i]==0.0)
00127 v[i]=1e-16;
00128 }
00129
00130 return (v!=NULL);
00131 }
00132
00133 protected:
00135 float64_t* diag_lhs;
00137 float64_t* diag_rhs;
00139 bool use_optimized_diagonal_computation;
00140 };
00141 }
00142 #endif