Line data    Source code

       1             : /*************************************************************************
       2             :  *
       3             :  *  Project
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      12             :  *
      13             :  * Copyright (C) Akiel Aries, <akiel@akiel.org>, et al.
      14             :  *
      15             :  * This software is licensed as described in the file LICENSE, which
      16             :  * you should have received as part of this distribution. The terms
      17             :  * among other details are referenced in the official documentation
      18             :  * seen here : https://akielaries.github.io/openGPMP/ along with
      19             :  * important files seen in this project.
      20             :  *
      21             :  * You may opt to use, copy, modify, merge, publish, distribute
      22             :  * and/or sell copies of the Software, and permit persons to whom
      23             :  * the Software is furnished to do so, under the terms of the
      24             :  * LICENSE file. As this is an Open Source effort, all implementations
      25             :  * must be of the same methodology.
      26             :  *
      27             :  *
      28             :  *
      29             :  * This software is distributed on an AS IS basis, WITHOUT
      30             :  * WARRANTY OF ANY KIND, either express or implied.
      31             :  *
      32             :  ************************************************************************/
      33             : #include <algorithm>
      34             : #include <functional>
      35             : #include <numeric>
      36             : #include <openGPMP/ml/kfold.hpp>
      37             : #include <stdexcept>
      38             : 
      39           0 : gpmp::ml::Kfold::Kfold(int fold) : k(fold) {
      40           0 : }
      41             : 
      42           0 : gpmp::ml::Kfold::~Kfold() {
      43           0 : }
      44             : 
      45           0 : void gpmp::ml::Kfold::split_indices(int num_instances) {
      46           0 :     if (k <= 1 || num_instances <= 0) {
      47           0 :         throw std::invalid_argument(
      48           0 :             "Invalid value of k or number of instances.");
      49             :     }
      50             : 
      51             :     // Initialize fold_indices with k empty vectors
      52           0 :     fold_indices.clear();
      53           0 :     fold_indices.resize(k);
      54             : 
      55             :     // Assign indices to each fold
      56           0 :     int fold_size = num_instances / k;
      57           0 :     int remainder = num_instances % k;
      58           0 :     int start_index = 0;
      59           0 :     for (int i = 0; i < k; ++i) {
      60           0 :         int fold_length = fold_size + (i < remainder ? 1 : 0);
      61           0 :         std::vector<int> indices(fold_length);
      62           0 :         std::iota(indices.begin(), indices.end(), start_index);
      63           0 :         fold_indices[i] = indices;
      64           0 :         start_index += fold_length;
      65           0 :     }
      66           0 : }
      67             : 
      68           0 : void gpmp::ml::Kfold::perform_cross_validation(
      69             :     std::function<void(int, int)> train_and_test_func) {
      70           0 :     if (fold_indices.empty()) {
      71           0 :         throw std::logic_error("Indices not split. Call split_indices before "
      72           0 :                                "performing cross-validation.");
      73             :     }
      74             : 
      75           0 :     for (int i = 0; i < k; ++i) {
      76             :         // Use fold i as the validation set, train on all other folds
      77           0 :         std::vector<int> validation_indices = fold_indices[i];
      78           0 :         for (int j = 0; j < k; ++j) {
      79           0 :             if (j != i) {
      80           0 :                 for (int index : fold_indices[j]) {
      81           0 :                     train_and_test_func(j, index);
      82             :                 }
      83             :             }
      84             :         }
      85           0 :     }
      86           0 : }