| 7 | |
| 8 | using namespace svm_kernel; |
| 9 | KernelMatrix::KernelMatrix(const DataSet::node2d &instances, SvmParam param) { |
| 10 | n_instances_ = instances.size(); |
| 11 | n_features_ = 0; |
| 12 | this->param = param; |
| 13 | |
| 14 | //three arrays for csr representation |
| 15 | vector<kernel_type> csr_val; |
| 16 | vector<int> csr_col_ind;//index of each value of all the instances |
| 17 | vector<int> csr_row_ptr(1, 0);//the start positions of the instances |
| 18 | |
| 19 | vector<kernel_type> csr_self_dot; |
| 20 | for (int i = 0; i < n_instances_; ++i) {//convert libsvm format to csr format |
| 21 | float_type self_dot = 0; |
| 22 | for (int j = 0; j < instances[i].size(); ++j) { |
| 23 | csr_val.push_back(instances[i][j].value); |
| 24 | self_dot += instances[i][j].value * instances[i][j].value; |
| 25 | csr_col_ind.push_back(instances[i][j].index);//libSVM data format is one-based, convert to zero-based |
| 26 | if (instances[i][j].index > n_features_) n_features_ = instances[i][j].index; |
| 27 | } |
| 28 | csr_row_ptr.push_back(csr_row_ptr.back() + instances[i].size()); |
| 29 | csr_self_dot.push_back(self_dot); |
| 30 | } |
| 31 | n_features_++; |
| 32 | |
| 33 | //three arrays (on GPU/CPU) for csr representation |
| 34 | val_.resize(csr_val.size()); |
| 35 | col_ind_.resize(csr_col_ind.size()); |
| 36 | row_ptr_.resize(csr_row_ptr.size()); |
| 37 | //copy data to the three arrays |
| 38 | val_.copy_from(csr_val.data(), val_.size()); |
| 39 | col_ind_.copy_from(csr_col_ind.data(), col_ind_.size()); |
| 40 | row_ptr_.copy_from(csr_row_ptr.data(), row_ptr_.size()); |
| 41 | |
| 42 | self_dot_.resize(n_instances_); |
| 43 | self_dot_.copy_from(csr_self_dot.data(), self_dot_.size()); |
| 44 | |
| 45 | nnz_ = csr_val.size();//number of nonzero |
| 46 | |
| 47 | //pre-compute diagonal elements |
| 48 | |
| 49 | diag_.resize(n_instances_); |
| 50 | switch (param.kernel_type) { |
| 51 | case SvmParam::RBF: |
| 52 | case SvmParam::PRECOMPUTED://precomputed uses rbf as default |
| 53 | for (int i = 0; i < n_instances_; ++i) { |
| 54 | diag_.host_data()[i] = 1;//rbf kernel |
| 55 | } |
| 56 | break; |
| 57 | case SvmParam::LINEAR: |
| 58 | diag_.copy_from(self_dot_); |
| 59 | break; |
| 60 | case SvmParam::POLY: |
| 61 | diag_.copy_from(self_dot_); |
| 62 | poly_kernel(diag_, param.gamma, param.coef0, param.degree, diag_.size()); |
| 63 | break; |
| 64 | case SvmParam::SIGMOID: |
| 65 | diag_.copy_from(self_dot_); |
| 66 | sigmoid_kernel(diag_, param.gamma, param.coef0, diag_.size()); |
nothing calls this directly
no test coverage detected