SqrtDiagKernelNormalizer.h
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00011 #ifndef _SQRTDIAGKERNELNORMALIZER_H___
00012 #define _SQRTDIAGKERNELNORMALIZER_H___
00013
00014 #include "kernel/KernelNormalizer.h"
00015 #include "kernel/CommWordStringKernel.h"
00016
00027 class CSqrtDiagKernelNormalizer : public CKernelNormalizer
00028 {
00029 public:
00034 CSqrtDiagKernelNormalizer(bool use_opt_diag=false): sqrtdiag_lhs(NULL),
00035 sqrtdiag_rhs(NULL), use_optimized_diagonal_computation(use_opt_diag)
00036 {
00037 }
00038
00040 virtual ~CSqrtDiagKernelNormalizer()
00041 {
00042 delete[] sqrtdiag_lhs;
00043 delete[] sqrtdiag_rhs;
00044 }
00045
00048 virtual bool init(CKernel* k)
00049 {
00050 ASSERT(k);
00051 int32_t num_lhs=k->get_num_vec_lhs();
00052 int32_t num_rhs=k->get_num_vec_rhs();
00053 ASSERT(num_lhs>0);
00054 ASSERT(num_rhs>0);
00055
00056 CFeatures* old_lhs=k->lhs;
00057 CFeatures* old_rhs=k->rhs;
00058
00059 k->lhs=old_lhs;
00060 k->rhs=old_lhs;
00061 bool r1=alloc_and_compute_diag(k, sqrtdiag_lhs, num_lhs);
00062
00063 k->lhs=old_rhs;
00064 k->rhs=old_rhs;
00065 bool r2=alloc_and_compute_diag(k, sqrtdiag_rhs, num_rhs);
00066
00067 k->lhs=old_lhs;
00068 k->rhs=old_rhs;
00069
00070 return r1 && r2;
00071 }
00072
00078 inline virtual float64_t normalize(
00079 float64_t value, int32_t idx_lhs, int32_t idx_rhs)
00080 {
00081 float64_t sqrt_both=sqrtdiag_lhs[idx_lhs]*sqrtdiag_rhs[idx_rhs];
00082 return value/sqrt_both;
00083 }
00084
00089 inline virtual float64_t normalize_lhs(float64_t value, int32_t idx_lhs)
00090 {
00091 return value/sqrtdiag_lhs[idx_lhs];
00092 }
00093
00098 inline virtual float64_t normalize_rhs(float64_t value, int32_t idx_rhs)
00099 {
00100 return value/sqrtdiag_rhs[idx_rhs];
00101 }
00102
00103 public:
00108 bool alloc_and_compute_diag(CKernel* k, float64_t* &v, int32_t num)
00109 {
00110 delete[] v;
00111 v=new float64_t[num];
00112
00113 for (int32_t i=0; i<num; i++)
00114 {
00115 if (k->get_kernel_type() == K_COMMWORDSTRING)
00116 {
00117 if (use_optimized_diagonal_computation)
00118 v[i]=sqrt(((CCommWordStringKernel*) k)->compute_diag(i));
00119 else
00120 v[i]=sqrt(((CCommWordStringKernel*) k)->compute_helper(i,i, true));
00121 }
00122 else
00123 v[i]=sqrt(k->compute(i,i));
00124
00125 if (v[i]==0.0)
00126 v[i]=1e-16;
00127 }
00128
00129 return (v!=NULL);
00130 }
00131
00133 inline virtual const char* get_name() const { return "SqrtDiagKernelNormalizer"; }
00134
00135 protected:
00137 float64_t* sqrtdiag_lhs;
00139 float64_t* sqrtdiag_rhs;
00141 bool use_optimized_diagonal_computation;
00142 };
00143
00144 #endif