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 using namespace shogun;
00018 
00019 CTensorProductPairKernel::CTensorProductPairKernel(int32_t size, CKernel* s)
00020 : CSimpleKernel<int32_t>(size), subkernel(s)
00021 {
00022     SG_REF(subkernel);
00023 }
00024 
00025 CTensorProductPairKernel::CTensorProductPairKernel(CSimpleFeatures<int32_t>* l, CSimpleFeatures<int32_t>* r, CKernel* s)
00026 : CSimpleKernel<int32_t>(10), subkernel(s)
00027 {
00028     SG_REF(subkernel);
00029     init(l, r);
00030 }
00031 
00032 CTensorProductPairKernel::~CTensorProductPairKernel()
00033 {
00034     SG_UNREF(subkernel);
00035     cleanup();
00036 }
00037 
00038 bool CTensorProductPairKernel::init(CFeatures* l, CFeatures* r)
00039 {
00040     CSimpleKernel<int32_t>::init(l, r);
00041     init_normalizer();
00042     return true;
00043 }
00044 
00045 float64_t CTensorProductPairKernel::compute(int32_t idx_a, int32_t idx_b)
00046 {
00047   int32_t alen, blen;
00048   bool afree, bfree;
00049 
00050   int32_t* avec=((CSimpleFeatures<int32_t>*) lhs)->get_feature_vector(idx_a, alen, afree);
00051   int32_t* bvec=((CSimpleFeatures<int32_t>*) rhs)->get_feature_vector(idx_b, blen, bfree);
00052 
00053   ASSERT(alen==2);
00054   ASSERT(blen==2);
00055 
00056   CKernel* k=subkernel;
00057   ASSERT(k && k->has_features());
00058 
00059   int32_t a=avec[0];
00060   int32_t b=avec[1];
00061   int32_t c=bvec[0];
00062   int32_t d=bvec[1];
00063 
00064   float64_t result = k->kernel(a,c)*k->kernel(b,d) + k->kernel(a,d)*k->kernel(b,c);
00065 
00066   ((CSimpleFeatures<int32_t>*) lhs)->free_feature_vector(avec, idx_a, afree);
00067   ((CSimpleFeatures<int32_t>*) rhs)->free_feature_vector(bvec, idx_b, bfree);
00068 
00069   return result;
00070 }
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