decision-tree-classifier

commit 333e4207d7e436660537738c05c0284893d5717e
parent fd65d662d1afca9132e08c51d2958600a37200ec
Author: Andrew <andrewlaack1@gmail.com>
Date:   Fri, 20 Dec 2024 04:02:32 -0600

Started over in c++

Diffstat:
A
rewrite/DecisionTreeClassifier.cpp
 | 
11
+++++++++++
A
rewrite/DecisionTreeClassifier.h
 | 
8
++++++++
A
rewrite/Makefile
 | 
12
++++++++++++
A
rewrite/Tests.cpp
 | 
52
++++++++++++++++++++++++++++++++++++++++++++++++++++
A
rewrite/TreeNode.cpp
 | 
87
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
A
rewrite/TreeNode.h
 | 
16
++++++++++++++++

6 files changed, 186 insertions(+), 0 deletions(-)
diff --git a/rewrite/DecisionTreeClassifier.cpp b/rewrite/DecisionTreeClassifier.cpp
@@ -0,0 +1,11 @@
+#include "DecisionTreeClassifier.h"
+#include "TreeNode.h"
+
+using namespace std;
+
+DecisionTreeClassifier::DecisionTreeClassifier(int maxDepth){
+	depth = maxDepth;
+}
+
+void DecisionTreeClassifier::fit(float* X, int rows, int* y, int columns){
+}
diff --git a/rewrite/DecisionTreeClassifier.h b/rewrite/DecisionTreeClassifier.h
@@ -0,0 +1,8 @@
+class DecisionTreeClassifier{
+	public:
+		DecisionTreeClassifier(int depth);
+		void fit(float* X, int rows, int* y, int columns);
+		int* predict();
+	private:
+		int depth;
+};
diff --git a/rewrite/Makefile b/rewrite/Makefile
@@ -0,0 +1,12 @@
+clean:
+	rm *.o
+	rm *.out
+
+node:
+	g++ -c TreeNode.cpp
+
+tests: DecisionTreeClassifier.o TreeNode.o
+	g++ Tests.cpp DecisionTreeClassifier.o TreeNode.o
+
+decisionTree:
+	g++ -c DecisionTreeClassifier.cpp
diff --git a/rewrite/Tests.cpp b/rewrite/Tests.cpp
@@ -0,0 +1,52 @@
+#include "DecisionTreeClassifier.h"
+#include "TreeNode.h"
+#include "iostream"
+#include "assert.h"
+
+using namespace std;
+
+
+
+void testTreeNode(){
+	int labels[] = {10, 10, 10, 1, 2, 3};
+	float samples[][4] = {
+		{1,1,5,3},
+		{1,2,5,3},
+		{1,7,5,3},
+		{1,3,5,3},
+		{1,7,5,3},
+		{1,1,5,3}
+	};
+
+	TreeNode tn = TreeNode(5.0f ,1);
+	bool isLeaf = tn.isLeaf();
+
+	assert(!isLeaf);
+	cout << "Is Leaf Passed" << "\n";
+
+	float giniVal = tn.evalSplit(*samples, labels, 6, 4, "gini");
+	assert(abs(giniVal - .5833333) < .0001 );
+
+	tn.setSplit(0.0f, 0);
+	float giniVal2 = tn.evalSplit(*samples, labels, 6, 4, "gini");
+	assert(abs(giniVal2 - .6666666) < .0001);
+
+	cout << "Gini Calculation Passed" << "\n";
+}
+
+int main(){
+	testTreeNode();
+	DecisionTreeClassifier clf = DecisionTreeClassifier(10);
+	int labels[] = {10, 10, 10, 1, 2, 3};
+
+	float samples[][4] = {
+		{1,1,5,3},
+		{1,2,5,3},
+		{1,7,5,3},
+		{1,3,5,3},
+		{1,7,5,3},
+		{1,1,5,3}
+	};
+
+	clf.fit(*samples, 6, labels, 4);
+}
diff --git a/rewrite/TreeNode.cpp b/rewrite/TreeNode.cpp
@@ -0,0 +1,87 @@
+#include "TreeNode.h"
+#include "stdexcept"
+#include "unordered_map"
+#include "math.h"
+#include "iostream"
+
+
+TreeNode::TreeNode(){
+	leaf = true;
+}
+
+TreeNode::TreeNode(float splittingVal, int featureIndex){
+	splitValue = splittingVal;
+	index = featureIndex;
+	leaf = false;
+}
+
+void TreeNode::setSplit(float splittingVal, int featureIndex){
+	splitValue = splittingVal;
+	index = featureIndex;
+	leaf = false;
+}
+
+bool TreeNode::isLeaf(){
+	return leaf;
+}
+
+float TreeNode::evalSplit(float* X, int* y, int samples, int features, std::string criterion){
+
+	if(isLeaf()){
+		throw std::logic_error("Cannot evaluate split on leaf node.");
+	}
+
+	if(criterion != "gini"){
+		throw std::invalid_argument("Gini impurity is the only supported criterion.");
+	}
+
+	return giniImpurity(X, y, samples, features);
+}
+
+float TreeNode::giniImpurity(float* X, int* y, int samples, int features){
+
+
+
+
+	std::unordered_map<int, int> ltMap;
+	std::unordered_map<int, int> gtMap;
+
+	int ltCount = 0;
+	int gteqCount = 0;
+
+	for(int i = 0; i < samples; ++i){
+		if(X[index + (i * features)] < splitValue){
+			ltMap[y[i]]++;
+			ltCount++;
+		}
+		else{
+			gtMap[y[i]]++;
+			gteqCount++;
+		}
+	}
+
+
+	float ltGini= 1.0f;
+
+	for (const auto& pair : ltMap) {
+		ltGini -= pow(float(pair.second) / ltCount, 2);
+	}
+
+	float gteqGini = 1.0f;
+
+	for (const auto& pair : gtMap) {
+		gteqGini -= pow(float(pair.second) / gteqCount, 2);
+	}
+
+	if(gteqCount == 0){
+		gteqGini = 0.0f;
+	}
+	if(ltCount == 0){
+		ltGini = 0.0f;
+	}
+
+	float gini = gteqGini * float(gteqCount) / samples;
+	gini += ltGini * float(ltCount) / samples;
+
+	return gini;
+}
diff --git a/rewrite/TreeNode.h b/rewrite/TreeNode.h
@@ -0,0 +1,16 @@
+#include "string"
+
+class TreeNode{
+	public:
+		TreeNode();
+		TreeNode(float splittingVal, int featureIndex);
+		bool isLeaf();
+		void setSplit(float splittingValue, int featureIndex);
+		float evalSplit(float* X, int* y, int samples, int features, std::string criterion);
+
+	private:
+		bool leaf;
+		float splitValue;
+		int index;
+		float giniImpurity(float* X, int* y, int samples, int features);
+};