Refactor BaseClassifier and begin TAN impl.

src/TAN.cc

@@ -0,0 +1,25 @@
+#include "TAN.h"
+
+namespace bayesnet {
+    using namespace std;
+    using namespace torch;
+
+    TAN::TAN() : BaseClassifier(Network()) {}
+
+    void TAN::train()
+    {
+        // 0. Add all nodes to the model
+        addNodes();
+        // 1. Compute mutual information between each feature and the class
+        auto weights = metrics.conditionalEdge();
+        // 2. Compute the maximum spanning tree
+        auto mst = metrics.maximumSpanningTree(weights);
+        // 3. Add edges from the maximum spanning tree to the model
+        for (auto i = 0; i < mst.size(); ++i) {
+            auto [from, to] = mst[i];
+            model.addEdge(features[from], features[to]);
+        }
+
+    }
+
+}