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
00026 class CSqrtDiagKernelNormalizer : public CKernelNormalizer
00027 {
00028 public:
00033 CSqrtDiagKernelNormalizer(bool use_opt_diag=false): sqrtdiag_lhs(NULL),
00034 sqrtdiag_rhs(NULL), use_optimized_diagonal_computation(use_opt_diag)
00035 {
00036 }
00037
00039 virtual ~CSqrtDiagKernelNormalizer()
00040 {
00041 delete[] sqrtdiag_lhs;
00042 delete[] sqrtdiag_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, sqrtdiag_lhs, num_lhs);
00061
00062 k->lhs=old_rhs;
00063 k->rhs=old_rhs;
00064 bool r2=alloc_and_compute_diag(k, sqrtdiag_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 sqrt_both=sqrtdiag_lhs[idx_lhs]*sqrtdiag_rhs[idx_rhs];
00081 return value/sqrt_both;
00082 }
00083
00088 inline virtual float64_t normalize_lhs(float64_t value, int32_t idx_lhs)
00089 {
00090 return value/sqrtdiag_lhs[idx_lhs];
00091 }
00092
00097 inline virtual float64_t normalize_rhs(float64_t value, int32_t idx_rhs)
00098 {
00099 return value/sqrtdiag_rhs[idx_rhs];
00100 }
00101
00102 public:
00107 bool alloc_and_compute_diag(CKernel* k, float64_t* &v, int32_t num)
00108 {
00109 delete[] v;
00110 v=new float64_t[num];
00111
00112 for (int32_t i=0; i<num; i++)
00113 {
00114 if (k->get_kernel_type() == K_COMMWORDSTRING)
00115 {
00116 if (use_optimized_diagonal_computation)
00117 v[i]=sqrt(((CCommWordStringKernel*) k)->compute_diag(i));
00118 else
00119 v[i]=sqrt(((CCommWordStringKernel*) k)->compute_helper(i,i, true));
00120 }
00121 else
00122 v[i]=sqrt(k->compute(i,i));
00123
00124 if (v[i]==0.0)
00125 v[i]=1e-16;
00126 }
00127
00128 return (v!=NULL);
00129 }
00130
00131 protected:
00133 float64_t* sqrtdiag_lhs;
00135 float64_t* sqrtdiag_rhs;
00137 bool use_optimized_diagonal_computation;
00138 };
00139
00140 #endif