SparsePolyKernel.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) 1999-2008 Soeren Sonnenburg
00008  * Copyright (C) 1999-2008 Fraunhofer Institute FIRST and Max-Planck-Society
00009  */
00010 
00011 #include "lib/common.h"
00012 #include "lib/io.h"
00013 #include "kernel/SparsePolyKernel.h"
00014 #include "kernel/SqrtDiagKernelNormalizer.h"
00015 #include "features/SparseFeatures.h"
00016 
00017 CSparsePolyKernel::CSparsePolyKernel(int32_t size, int32_t d, bool i)
00018 : CSparseKernel<float64_t>(size), degree(d), inhomogene(i)
00019 {
00020     set_normalizer(new CSqrtDiagKernelNormalizer());
00021 }
00022 
00023 CSparsePolyKernel::CSparsePolyKernel(
00024     CSparseFeatures<float64_t>* l, CSparseFeatures<float64_t>* r,
00025     int32_t size, int32_t d, bool i)
00026 : CSparseKernel<float64_t>(size),degree(d),inhomogene(i)
00027 {
00028     set_normalizer(new CSqrtDiagKernelNormalizer());
00029     init(l,r);
00030 }
00031 
00032 CSparsePolyKernel::~CSparsePolyKernel()
00033 {
00034     cleanup();
00035 }
00036 
00037 bool CSparsePolyKernel::init(CFeatures* l, CFeatures* r)
00038 {
00039     CSparseKernel<float64_t>::init(l,r);
00040     return init_normalizer();
00041 }
00042   
00043 void CSparsePolyKernel::cleanup()
00044 {
00045     CKernel::cleanup();
00046 }
00047 
00048 bool CSparsePolyKernel::load_init(FILE* src)
00049 {
00050     return false;
00051 }
00052 
00053 bool CSparsePolyKernel::save_init(FILE* dest)
00054 {
00055     return false;
00056 }
00057 
00058 float64_t CSparsePolyKernel::compute(int32_t idx_a, int32_t idx_b)
00059 {
00060   int32_t alen=0;
00061   int32_t blen=0;
00062   bool afree=false;
00063   bool bfree=false;
00064 
00065   TSparseEntry<float64_t>* avec=((CSparseFeatures<float64_t>*) lhs)->
00066     get_sparse_feature_vector(idx_a, alen, afree);
00067   TSparseEntry<float64_t>* bvec=((CSparseFeatures<float64_t>*) rhs)->
00068     get_sparse_feature_vector(idx_b, blen, bfree);
00069 
00070   float64_t result=((CSparseFeatures<float64_t>*) lhs)->sparse_dot(1.0,avec, alen, bvec, blen);
00071 
00072   if (inhomogene)
00073       result+=1;
00074 
00075   result=CMath::pow(result, degree);
00076 
00077   ((CSparseFeatures<float64_t>*) lhs)->free_feature_vector(avec, idx_a, afree);
00078   ((CSparseFeatures<float64_t>*) rhs)->free_feature_vector(bvec, idx_b, bfree);
00079 
00080   return result;
00081 }

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