From e689d1f69c02982c12cb13bf58de2b4f91892635 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ricardo=20Monta=C3=B1ana?= <rmontanana@gmail.com>
Date: Fri, 14 Apr 2023 11:53:16 +0200
Subject: [PATCH] refactor computing max_cuts

---
 CPPFImdlp.cpp             | 35 ++++++++++++++++++++++++++---------
 CPPFImdlp.h               | 10 ++++++----
 tests/FImdlp_unittest.cpp |  5 +++--
 3 files changed, 35 insertions(+), 15 deletions(-)

diff --git a/CPPFImdlp.cpp b/CPPFImdlp.cpp
index a57c9a9..79f9152 100644
--- a/CPPFImdlp.cpp
+++ b/CPPFImdlp.cpp
@@ -50,6 +50,13 @@ namespace mdlp {
         indices = sortIndices(X_, y_);
         metrics.setData(y, indices);
         computeCutPoints(0, X.size(), 1);
+        sort(cutPoints.begin(), cutPoints.end());
+        if (num_cut_points > 0) {
+            // Select the best (with lower entropy) cut points
+            while (cutPoints.size() > num_cut_points) {
+                resizeCutPoints();
+            }
+        }
     }
 
     pair<precision_t, size_t> CPPFImdlp::valueCutPoint(size_t start, size_t cut, size_t end) {
@@ -87,8 +94,6 @@ namespace mdlp {
     void CPPFImdlp::computeCutPoints(size_t start, size_t end, int depth_) {
         size_t cut;
         pair<precision_t, size_t> result;
-        if (cutPoints.size() == num_cut_points)
-            return;
         // Check if the interval length and the depth are Ok
         if (end - start < min_length || depth_ > max_depth)
             return;
@@ -174,12 +179,24 @@ namespace mdlp {
         return idx;
     }
 
-    cutPoints_t CPPFImdlp::getCutPoints() {
-        sort(cutPoints.begin(), cutPoints.end());
-        return cutPoints;
-    }
-
-    int CPPFImdlp::get_depth() const {
-        return depth;
+    void CPPFImdlp::resizeCutPoints() {
+        //Compute entropy of each of the whole cutpoint set and discards the biggest value
+        precision_t maxEntropy = 0;
+        precision_t entropy;
+        size_t maxEntropyIdx = 0;
+        size_t begin = 0;
+        size_t end;
+        for (size_t idx = 0; idx < cutPoints.size(); idx++) {
+            end = begin;
+            while (X[indices[end]] < cutPoints[idx] && end < X.size())
+                end++;
+            entropy = metrics.entropy(begin, end);
+            if (entropy > maxEntropy) {
+                maxEntropy = entropy;
+                maxEntropyIdx = idx;
+            }
+            begin = end;
+        }
+        cutPoints.erase(cutPoints.begin() + static_cast<long>(maxEntropyIdx));
     }
 }
diff --git a/CPPFImdlp.h b/CPPFImdlp.h
index c205719..29b76c6 100644
--- a/CPPFImdlp.h
+++ b/CPPFImdlp.h
@@ -21,10 +21,12 @@ namespace mdlp {
         cutPoints_t cutPoints;
         size_t num_cut_points = numeric_limits<size_t>::max();
 
-        static indices_t sortIndices(samples_t&, labels_t&);
+        static indices_t sortIndices(samples_t &, labels_t &);
 
         void computeCutPoints(size_t, size_t, int);
 
+        void resizeCutPoints();
+
         bool mdlp(size_t, size_t, size_t);
 
         size_t getCandidate(size_t, size_t);
@@ -40,11 +42,11 @@ namespace mdlp {
 
         ~CPPFImdlp();
 
-        void fit(samples_t&, labels_t&);
+        void fit(samples_t &, labels_t &);
 
-        cutPoints_t getCutPoints();
+        inline cutPoints_t getCutPoints() const { return cutPoints; };
 
-        int get_depth() const;
+        inline int get_depth() const { return depth; };
 
         static inline string version() { return "1.1.1"; };
     };
diff --git a/tests/FImdlp_unittest.cpp b/tests/FImdlp_unittest.cpp
index 1559fa3..d0da40e 100644
--- a/tests/FImdlp_unittest.cpp
+++ b/tests/FImdlp_unittest.cpp
@@ -269,12 +269,13 @@ namespace mdlp {
         auto test = CPPFImdlp(75, 2, 1);
         vector<cutPoints_t> expected = {
                 {5.45f},
-                {3.35f},
+                {2.85f},
                 {2.45f},
                 {0.8f}
         };
-        vector<int> depths = {1, 1, 1, 1};
+        vector<int> depths = {2, 2, 2, 2};
         test_dataset(test, "iris", expected, depths);
+        
     }
 
     TEST_F(TestFImdlp, MaxCutPointsFloat) {