AUCKernel.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 Gunnar Raetsch
00008  * Copyright (C) 1999-2008 Fraunhofer Institute FIRST and Max-Planck-Society
00009  */
00010 
00011 #include "lib/common.h"
00012 #include "lib/Mathematics.h"
00013 #include "kernel/AUCKernel.h"
00014 #include "features/WordFeatures.h"
00015 #include "lib/io.h"
00016 
00017 CAUCKernel::CAUCKernel(INT size, CKernel* s)
00018 : CSimpleKernel<WORD>(size), subkernel(s)
00019 {
00020 }
00021 
00022 CAUCKernel::CAUCKernel(CWordFeatures* l, CWordFeatures* r, CKernel* s)
00023 : CSimpleKernel<WORD>(10), subkernel(s)
00024 {
00025     init(l, r);
00026 }
00027 
00028 CAUCKernel::~CAUCKernel()
00029 {
00030     cleanup();
00031 }
00032   
00033 bool CAUCKernel::init(CFeatures* l, CFeatures* r)
00034 {
00035     CSimpleKernel<WORD>::init(l, r);
00036     return true;
00037 }
00038 
00039 bool CAUCKernel::load_init(FILE* src)
00040 {
00041     return false;
00042 }
00043 
00044 bool CAUCKernel::save_init(FILE* dest)
00045 {
00046     return false;
00047 }
00048   
00049 DREAL CAUCKernel::compute(INT idx_a, INT idx_b)
00050 {
00051   INT alen, blen;
00052   bool afree, bfree;
00053 
00054   WORD* avec=((CWordFeatures*) lhs)->get_feature_vector(idx_a, alen, afree);
00055   WORD* bvec=((CWordFeatures*) rhs)->get_feature_vector(idx_b, blen, bfree);
00056 
00057   ASSERT(alen==2);
00058   ASSERT(blen==2);
00059 
00060   ASSERT(subkernel && subkernel->has_features());
00061 
00062   DREAL k11,k12,k21,k22 ;
00063   INT idx_a1=avec[0], idx_a2=avec[1], idx_b1=bvec[0], idx_b2=bvec[1] ;
00064   
00065   k11 = subkernel->kernel(idx_a1,idx_b1) ;
00066   k12 = subkernel->kernel(idx_a1,idx_b2) ;
00067   k21 = subkernel->kernel(idx_a2,idx_b1) ;  
00068   k22 = subkernel->kernel(idx_a2,idx_b2) ;
00069 
00070   DREAL result = k11+k22-k21-k12 ;
00071 
00072   ((CWordFeatures*) lhs)->free_feature_vector(avec, idx_a, afree);
00073   ((CWordFeatures*) rhs)->free_feature_vector(bvec, idx_b, bfree);
00074 
00075   return result;
00076 }

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