Add max_depth and min_length as hyperparams

CPPFImdlp.cpp

@@ -8,7 +8,11 @@
 
 namespace mdlp {
 
-    CPPFImdlp::CPPFImdlp(): indices(indices_t()), X(samples_t()), y(labels_t()),
+    CPPFImdlp::CPPFImdlp():depth(0), max_depth(numeric_limits<int>::max()), min_length(3), indices(indices_t()), X(samples_t()), y(labels_t()),
+        metrics(Metrics(y, indices))
+    {
+    }
+    CPPFImdlp::CPPFImdlp(int min_length_, int max_depth_): depth(0), max_depth(max_depth_), min_length(min_length_), indices(indices_t()), X(samples_t()), y(labels_t()),
         metrics(Metrics(y, indices))
     {
     }
@@ -25,9 +29,15 @@ namespace mdlp {
         if (X.empty() || y.empty()) {
             throw invalid_argument("X and y must have at least one element");
         }
+        if (min_length < 3) {
+            throw invalid_argument("min_length must be greater than 2");
+        }
+        if (max_depth < 1) {
+            throw invalid_argument("max_depth must be greater than 0");
+        }
         indices = sortIndices(X_, y_);
         metrics.setData(y, indices);
-        computeCutPoints(0, X.size());
+        computeCutPoints(0, X.size(), 1);
         return *this;
     }
 
@@ -60,12 +70,14 @@ namespace mdlp {
         return { (actual + previous) / 2, cut };
     }
 
-    void CPPFImdlp::computeCutPoints(size_t start, size_t end)
+    void CPPFImdlp::computeCutPoints(size_t start, size_t end, int depth_)
     {
         size_t cut;
         pair<precision_t, size_t> result;
-        if (end - start < 3)
+        // Check if the interval length and the depth are Ok
+        if (end - start < min_length || depth_ > max_depth)
             return;
+        depth = depth_ > depth ? depth_ : depth;
         cut = getCandidate(start, end);
         if (cut == numeric_limits<size_t>::max())
             return;
@@ -73,8 +85,8 @@ namespace mdlp {
             result = valueCutPoint(start, cut, end);
             cut = result.second;
             cutPoints.push_back(result.first);
-            computeCutPoints(start, cut);
-            computeCutPoints(cut, end);
+            computeCutPoints(start, cut, depth_ + 1);
+            computeCutPoints(cut, end, depth_ + 1);
         }
     }
 
@@ -158,4 +170,8 @@ namespace mdlp {
         sort(output.begin(), output.end());
         return output;
     }
+    int CPPFImdlp::get_depth()
+    {
+        return depth;
+    }
 }