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 <shogun/lib/common.h>
00012 #include <shogun/mathematics/Math.h>
00013 #include <shogun/kernel/TensorProductPairKernel.h>
00014 #include <shogun/features/SimpleFeatures.h>
00015 #include <shogun/io/SGIO.h>
00016 
00017 using namespace shogun;
00018 
00019 CTensorProductPairKernel::CTensorProductPairKernel(void)
00020 : CDotKernel(0), subkernel(NULL)
00021 {
00022     register_params();
00023 }
00024 
00025 CTensorProductPairKernel::CTensorProductPairKernel(int32_t size, CKernel* s)
00026 : CDotKernel(size), subkernel(s)
00027 {
00028     SG_REF(subkernel);
00029     register_params();
00030 }
00031 
00032 CTensorProductPairKernel::CTensorProductPairKernel(CSimpleFeatures<int32_t>* l, CSimpleFeatures<int32_t>* r, CKernel* s)
00033 : CDotKernel(10), subkernel(s)
00034 {
00035     SG_REF(subkernel);
00036     init(l, r);
00037     register_params();
00038 }
00039 
00040 CTensorProductPairKernel::~CTensorProductPairKernel()
00041 {
00042     SG_UNREF(subkernel);
00043     cleanup();
00044 }
00045 
00046 bool CTensorProductPairKernel::init(CFeatures* l, CFeatures* r)
00047 {
00048     CDotKernel::init(l, r);
00049     init_normalizer();
00050     return true;
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 }
00079 
00080 void CTensorProductPairKernel::register_params()
00081 {
00082     m_parameters->add((CSGObject**)&subkernel, "subkernel", "the subkernel");
00083 }
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