TensorProductPairKernel.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) 2009 Soeren Sonnenburg
00008  * Copyright (C) 2009 Fraunhofer Institute FIRST and Max-Planck-Society
00009  */
00010 
00011 #include "lib/common.h"
00012 #include "lib/Mathematics.h"
00013 #include "kernel/TensorProductPairKernel.h"
00014 #include "features/SimpleFeatures.h"
00015 #include "lib/io.h"
00016 
00017 CTensorProductPairKernel::CTensorProductPairKernel(int32_t size, CKernel* s)
00018 : CSimpleKernel<int32_t>(size), subkernel(s)
00019 {
00020     SG_REF(subkernel);
00021 }
00022 
00023 CTensorProductPairKernel::CTensorProductPairKernel(CSimpleFeatures<int32_t>* l, CSimpleFeatures<int32_t>* r, CKernel* s)
00024 : CSimpleKernel<int32_t>(10), subkernel(s)
00025 {
00026     SG_REF(subkernel);
00027     init(l, r);
00028 }
00029 
00030 CTensorProductPairKernel::~CTensorProductPairKernel()
00031 {
00032     SG_UNREF(subkernel);
00033     cleanup();
00034 }
00035 
00036 bool CTensorProductPairKernel::init(CFeatures* l, CFeatures* r)
00037 {
00038     CSimpleKernel<int32_t>::init(l, r);
00039     init_normalizer();
00040     return true;
00041 }
00042 
00043 bool CTensorProductPairKernel::load_init(FILE* src)
00044 {
00045     return false;
00046 }
00047 
00048 bool CTensorProductPairKernel::save_init(FILE* dest)
00049 {
00050     return false;
00051 }
00052 
00053 float64_t CTensorProductPairKernel::compute(int32_t idx_a, int32_t idx_b)
00054 {
00055   int32_t alen, blen;
00056   bool afree, bfree;
00057 
00058   int32_t* avec=((CSimpleFeatures<int32_t>*) lhs)->get_feature_vector(idx_a, alen, afree);
00059   int32_t* bvec=((CSimpleFeatures<int32_t>*) rhs)->get_feature_vector(idx_b, blen, bfree);
00060 
00061   ASSERT(alen==2);
00062   ASSERT(blen==2);
00063 
00064   CKernel* k=subkernel;
00065   ASSERT(k && k->has_features());
00066 
00067   int32_t a=avec[0];
00068   int32_t b=avec[1];
00069   int32_t c=bvec[0];
00070   int32_t d=bvec[1];
00071 
00072   float64_t result = k->kernel(a,c)*k->kernel(b,d) + k->kernel(a,d)*k->kernel(b,c);
00073 
00074   ((CSimpleFeatures<int32_t>*) lhs)->free_feature_vector(avec, idx_a, afree);
00075   ((CSimpleFeatures<int32_t>*) rhs)->free_feature_vector(bvec, idx_b, bfree);
00076 
00077   return result;
00078 }

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