PolyMatchStringKernel.cpp

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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) 1999-2009 Soeren Sonnenburg
00008  * Copyright (C) 1999-2009 Fraunhofer Institute FIRST and Max-Planck-Society
00009  */
00010 
00011 #include "lib/common.h"
00012 #include "lib/io.h"
00013 #include "kernel/PolyMatchStringKernel.h"
00014 #include "kernel/SqrtDiagKernelNormalizer.h"
00015 #include "features/Features.h"
00016 #include "features/StringFeatures.h"
00017 
00018 CPolyMatchStringKernel::CPolyMatchStringKernel(int32_t size, int32_t d, bool i)
00019 : CStringKernel<char>(size), degree(d), inhomogene(i)
00020 {
00021     set_normalizer(new CSqrtDiagKernelNormalizer());
00022 }
00023 
00024 CPolyMatchStringKernel::CPolyMatchStringKernel(
00025     CStringFeatures<char>* l, CStringFeatures<char>* r, int32_t d, bool i)
00026 : CStringKernel<char>(10), degree(d), inhomogene(i)
00027 {
00028     set_normalizer(new CSqrtDiagKernelNormalizer());
00029     init(l, r);
00030 }
00031 
00032 CPolyMatchStringKernel::~CPolyMatchStringKernel()
00033 {
00034     cleanup();
00035 }
00036 
00037 bool CPolyMatchStringKernel::init(CFeatures* l, CFeatures* r)
00038 {
00039     CStringKernel<char>::init(l, r);
00040     return init_normalizer();
00041 }
00042 
00043 void CPolyMatchStringKernel::cleanup()
00044 {
00045     CKernel::cleanup();
00046 }
00047 
00048 bool CPolyMatchStringKernel::load_init(FILE *src)
00049 {
00050     return false;
00051 }
00052 
00053 bool CPolyMatchStringKernel::save_init(FILE *dest)
00054 {
00055     return false;
00056 }
00057 
00058 float64_t CPolyMatchStringKernel::compute(int32_t idx_a, int32_t idx_b)
00059 {
00060     int32_t i, alen, blen, sum;
00061 
00062     char* avec = ((CStringFeatures<char>*) lhs)->get_feature_vector(idx_a, alen);
00063     char* bvec = ((CStringFeatures<char>*) rhs)->get_feature_vector(idx_b, blen);
00064 
00065     ASSERT(alen==blen);
00066     for (i = 0, sum = inhomogene; i<alen; i++)
00067     {
00068         if (avec[i]==bvec[i])
00069             sum++;
00070     }
00071     return CMath::pow((float64_t) sum, degree);
00072 }

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