LibSVM.cpp
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00011 #include "classifier/svm/LibSVM.h"
00012 #include "lib/io.h"
00013
00014 using namespace shogun;
00015
00016 #ifdef HAVE_BOOST_SERIALIZATION
00017 #include <boost/serialization/export.hpp>
00018 BOOST_CLASS_EXPORT(CLibSVM);
00019 #endif //HAVE_BOOST_SERIALIZATION
00020
00021 CLibSVM::CLibSVM(LIBSVM_SOLVER_TYPE st)
00022 : CSVM(), model(NULL), solver_type(st)
00023 {
00024 }
00025
00026 CLibSVM::CLibSVM(float64_t C, CKernel* k, CLabels* lab)
00027 : CSVM(C, k, lab), model(NULL), solver_type(LIBSVM_C_SVC)
00028 {
00029 problem = svm_problem();
00030 }
00031
00032 CLibSVM::~CLibSVM()
00033 {
00034 }
00035
00036
00037 bool CLibSVM::train(CFeatures* data)
00038 {
00039 struct svm_node* x_space;
00040
00041 ASSERT(labels && labels->get_num_labels());
00042 ASSERT(labels->is_two_class_labeling());
00043
00044 if (data)
00045 {
00046 if (labels->get_num_labels() != data->get_num_vectors())
00047 SG_ERROR("Number of training vectors does not match number of labels\n");
00048 kernel->init(data, data);
00049 }
00050
00051 problem.l=labels->get_num_labels();
00052 SG_INFO( "%d trainlabels\n", problem.l);
00053
00054
00055
00056 if (!linear_term.empty() && labels->get_num_labels() != (int32_t)linear_term.size())
00057 SG_ERROR("Number of training vectors does not match length of linear term\n");
00058
00059
00060 if (!linear_term.empty()) {
00061
00062
00063 problem.pv = get_linear_term_array();
00064
00065 } else {
00066
00067
00068 problem.pv = new float64_t[problem.l];
00069
00070 for (int i=0; i!=problem.l; i++) {
00071 problem.pv[i] = -1.0;
00072 }
00073 }
00074
00075
00076
00077 problem.y=new float64_t[problem.l];
00078 problem.x=new struct svm_node*[problem.l];
00079 problem.C=new float64_t[problem.l];
00080
00081
00082 x_space=new struct svm_node[2*problem.l];
00083
00084 for (int32_t i=0; i<problem.l; i++)
00085 {
00086 problem.y[i]=labels->get_label(i);
00087 problem.x[i]=&x_space[2*i];
00088 x_space[2*i].index=i;
00089 x_space[2*i+1].index=-1;
00090 }
00091
00092 int32_t weights_label[2]={-1,+1};
00093 float64_t weights[2]={1.0,get_C2()/get_C1()};
00094
00095 ASSERT(kernel && kernel->has_features());
00096 ASSERT(kernel->get_num_vec_lhs()==problem.l);
00097
00098 param.svm_type=solver_type;
00099 param.kernel_type = LINEAR;
00100 param.degree = 3;
00101 param.gamma = 0;
00102 param.coef0 = 0;
00103 param.nu = get_nu();
00104 param.kernel=kernel;
00105 param.cache_size = kernel->get_cache_size();
00106 param.C = get_C1();
00107 param.eps = epsilon;
00108 param.p = 0.1;
00109 param.shrinking = 1;
00110 param.nr_weight = 2;
00111 param.weight_label = weights_label;
00112 param.weight = weights;
00113 param.use_bias = get_bias_enabled();
00114
00115 const char* error_msg = svm_check_parameter(&problem, ¶m);
00116
00117 if(error_msg)
00118 SG_ERROR("Error: %s\n",error_msg);
00119
00120 model = svm_train(&problem, ¶m);
00121
00122 if (model)
00123 {
00124 ASSERT(model->nr_class==2);
00125 ASSERT((model->l==0) || (model->l>0 && model->SV && model->sv_coef && model->sv_coef[0]));
00126
00127 int32_t num_sv=model->l;
00128
00129 create_new_model(num_sv);
00130 CSVM::set_objective(model->objective);
00131
00132 float64_t sgn=model->label[0];
00133
00134 set_bias(-sgn*model->rho[0]);
00135
00136 for (int32_t i=0; i<num_sv; i++)
00137 {
00138 set_support_vector(i, (model->SV[i])->index);
00139 set_alpha(i, sgn*model->sv_coef[0][i]);
00140 }
00141
00142 delete[] problem.x;
00143 delete[] problem.y;
00144 delete[] problem.pv;
00145 delete[] problem.C;
00146
00147
00148 delete[] x_space;
00149
00150 svm_destroy_model(model);
00151 model=NULL;
00152 return true;
00153 }
00154 else
00155 return false;
00156 }