Begin Ensemble

src/BaseClassifier.cc

@@ -80,16 +80,22 @@ namespace bayesnet {
     }
     Tensor BaseClassifier::predict(Tensor& X)
     {
-        auto m_ = X.size(0);
-        auto n_ = X.size(1);
-        vector<vector<int>> Xd(n_, vector<int>(m_, 0));
-        for (auto i = 0; i < n_; i++) {
-            auto temp = X.index({ "...", i });
-            Xd[i] = vector<int>(temp.data_ptr<int>(), temp.data_ptr<int>() + m_);
+        auto n_models = models.size();
+        Tensor y_pred = torch::zeros({ X.size(0), n_models }, torch::kInt64);
+        for (auto i = 0; i < n_models; ++i) {
+            y_pred.index_put_({ "...", i }, models[i].predict(X));
         }
-        auto yp = model.predict(Xd);
-        auto ypred = torch::tensor(yp, torch::kInt64);
-        return ypred;
+        auto y_pred_ = y_pred.accessor<int64_t, 2>();
+        vector<int> y_pred_final;
+        for (int i = 0; i < y_pred.size(0); ++i) {
+            vector<float> votes(states[className].size(), 0);
+            for (int j = 0; j < y_pred.size(1); ++j) {
+                votes[y_pred_[i][j]] += 1;
+            }
+            auto indices = argsort(votes);
+            y_pred_final.push_back(indices[0]);
+        }
+        return torch::tensor(y_pred_final, torch::kInt64);
     }
     float BaseClassifier::score(Tensor& X, Tensor& y)
     {

src/BaseClassifier.h

@@ -1,4 +1,5 @@
 #ifndef CLASSIFIERS_H
+#define CLASSIFIERS_H
 #include <torch/torch.h>
 #include "Network.h"
 #include "Metrics.hpp"

src/CMakeLists.txt

@@ -1,2 +1,2 @@
-add_library(BayesNet Network.cc Node.cc Metrics.cc BaseClassifier.cc KDB.cc TAN.cc SPODE.cc)
+add_library(BayesNet Network.cc Node.cc Metrics.cc BaseClassifier.cc KDB.cc TAN.cc SPODE.cc Ensemble.cc)
 target_link_libraries(BayesNet "${TORCH_LIBRARIES}")

src/Ensemble.cc

@@ -0,0 +1,61 @@
+#include "Ensemble.h"
+
+namespace bayesnet {
+    using namespace std;
+    using namespace torch;
+
+    Ensemble::Ensemble(BaseClassifier& model) : model(model), models(vector<BaseClassifier>()), m(0), n(0), metrics(Metrics()) {}
+    Ensemble& Ensemble::build(vector<string>& features, string className, map<string, vector<int>>& states)
+    {
+
+        dataset = torch::cat({ X, y.view({y.size(0), 1}) }, 1);
+        this->features = features;
+        this->className = className;
+        this->states = states;
+        auto n_classes = states[className].size();
+        metrics = Metrics(dataset, features, className, n_classes);
+        train();
+        return *this;
+    }
+    Ensemble& Ensemble::fit(Tensor& X, Tensor& y, vector<string>& features, string className, map<string, vector<int>>& states)
+    {
+        this->X = X;
+        this->y = y;
+        auto sizes = X.sizes();
+        m = sizes[0];
+        n = sizes[1];
+        return build(features, className, states);
+    }
+    Ensemble& Ensemble::fit(vector<vector<int>>& X, vector<int>& y, vector<string>& features, string className, map<string, vector<int>>& states)
+    {
+        this->X = torch::zeros({ static_cast<int64_t>(X[0].size()), static_cast<int64_t>(X.size()) }, kInt64);
+        for (int i = 0; i < X.size(); ++i) {
+            this->X.index_put_({ "...", i }, torch::tensor(X[i], kInt64));
+        }
+        this->y = torch::tensor(y, kInt64);
+        return build(features, className, states);
+    }
+    Tensor Ensemble::predict(Tensor& X)
+    {
+        auto m_ = X.size(0);
+        auto n_ = X.size(1);
+        vector<vector<int>> Xd(n_, vector<int>(m_, 0));
+        for (auto i = 0; i < n_; i++) {
+            auto temp = X.index({ "...", i });
+            Xd[i] = vector<int>(temp.data_ptr<int>(), temp.data_ptr<int>() + m_);
+        }
+        auto yp = model.predict(Xd);
+        auto ypred = torch::tensor(yp, torch::kInt64);
+        return ypred;
+    }
+    float Ensemble::score(Tensor& X, Tensor& y)
+    {
+        Tensor y_pred = predict(X);
+        return (y_pred == y).sum().item<float>() / y.size(0);
+    }
+    vector<string> Ensemble::show()
+    {
+        return model.show();
+    }
+
+}

src/Ensemble.h

@@ -0,0 +1,34 @@
+#ifndef ENSEMBLE_H
+#define ENSEMBLE_H
+#include <torch/torch.h>
+#include "BaseClassifier.h"
+#include "Metrics.hpp"
+using namespace std;
+using namespace torch;
+
+namespace bayesnet {
+    class Ensemble {
+    private:
+        Ensemble& build(vector<string>& features, string className, map<string, vector<int>>& states);
+    protected:
+        BaseClassifier& model;
+        vector<BaseClassifier> models;
+        int m, n; // m: number of samples, n: number of features
+        Tensor X;
+        Tensor y;
+        Tensor dataset;
+        Metrics metrics;
+        vector<string> features;
+        string className;
+        map<string, vector<int>> states;
+        void virtual train() = 0;
+    public:
+        Ensemble(BaseClassifier& model);
+        Ensemble& fit(Tensor& X, Tensor& y, vector<string>& features, string className, map<string, vector<int>>& states);
+        Ensemble& fit(vector<vector<int>>& X, vector<int>& y, vector<string>& features, string className, map<string, vector<int>>& states);
+        Tensor predict(Tensor& X);
+        float score(Tensor& X, Tensor& y);
+        vector<string> show();
+    };
+}
+#endif