src/filter.cpp

@@ -42,13 +42,13 @@ void SMSMessageFilter::GenerateProbability(std::string file_name) {
         while (std::getline(full_message, token, ' ')) {
             token = SanitizeToken(token);
             if (token.empty()) { continue; }
-            if (probability_dictionary[token] == 0) {
-                probability_dictionary[token] = 0.5;
-            }
             if (is_ham_temp) { 
-                probability_dictionary[token] += probability_dictionary[token] * 0.1;
+                probability_dictionary[token].value += probability_dictionary[token].value * 0.0000000001;
+                if (probability_dictionary[token].value > 1.) {
+                    probability_dictionary[token].value = 1.;
+                }
             } else {
-                probability_dictionary[token] -= probability_dictionary[token] * 0.1;
+                probability_dictionary[token].value -= probability_dictionary[token].value * 0.0000000001;
             } 
         }
         temp_message.clear();
@@ -82,7 +82,6 @@ void SMSMessageFilter::Prepare(std::string file_name) {
             full_message.clear();
             continue; // Probably a bad line cut
         }
-        full_message.ignore('\t');
         filtered_messages.emplace_back(is_ham_temp, full_message.str());
         temp_message.clear();
         full_message.clear();
@@ -97,15 +96,18 @@ void SMSMessageFilter::Filter(void) {
         full_message.str(filtered_messages[i].message);
         while (std::getline(full_message, token, ' ')) {
             token = SanitizeToken(token);
-            if (probability_dictionary[token] == 0) {
-                probability_dictionary[token] = 0.5;
-            }
-            type_probability = probability_dictionary[token] * type_probability;
+            type_probability = probability_dictionary[token].value * type_probability;
         }
+        double final_probability;
+        final_probability = (1. - sentence_probability_ham) * type_probability;
+        final_probability = final_probability / (final_probability + ((1. - type_probability) * sentence_probability_ham));
         if (type_probability <= sentence_probability_ham) {
             filtered_messages[i].is_ham_filter = true;
         } else { filtered_messages[i].is_ham_filter = false; }
+        std::cout << "[SMSMessageFilter - Info] Final probability of "
+                    << i << ":  " << final_probability << std::endl;
         type_probability = 0.5;
+        full_message.clear();
     }
 }
 
@@ -114,10 +116,10 @@ void SMSMessageFilter::Report(void) {
 }
 
 ReportData SMSMessageFilter::GenerateReport(void) {
-    double true_ham = 0;
-    double true_spam = 0;
-    double false_ham = 0;
-    double false_spam = 0;
+    double true_ham = 0.;
+    double true_spam = 0.;
+    double false_ham = 0.;
+    double false_spam = 0.;
     for (SMSMessage message : filtered_messages) {
         // Get total count
         if (!(message.is_ham ^ message.is_ham_filter)) {
@@ -129,6 +131,7 @@ ReportData SMSMessageFilter::GenerateReport(void) {
 
         }
     }
+    std::cout << std::endl;
     std::cout << "[SMSMessageFilter - Info] Ham barrier:        ";
     std::cout << sentence_probability_ham << std::endl;
     std::cout << "[SMSMessageFilter - Info] True ham:           ";
@@ -139,6 +142,7 @@ ReportData SMSMessageFilter::GenerateReport(void) {
     std::cout << false_ham << std::endl;
     std::cout << "[SMSMessageFilter - Info] False spam:         ";
     std::cout << false_spam << std::endl;
+    std::cout << std::endl;
 
     // Calculate report data
     ReportData new_report;
@@ -153,6 +157,8 @@ ReportData SMSMessageFilter::GenerateReport(void) {
 }
 
 void SMSMessageFilter::PrintReport(ReportData report) {
+    std::cout << std::endl;
+    std::cout << "============ [SMSMessageFilter - Report - Start] ============" << std::endl;
     // Spam precision: (true positives) / (true positives + false positives)
     std::cout << "[SMSMessageFilter - Report] Spam precision:   ";
     std::cout << report.spam_precision << std::endl;
@@ -180,6 +186,7 @@ void SMSMessageFilter::PrintReport(ReportData report) {
     // Accuracy: (spam recall + ham recall) / 2
     std::cout << "[SMSMessageFilter - Report] Accuracy:         ";
     std::cout << report.accuracy << std::endl;
+    std::cout << "============ [SMSMessageFilter - Report - End] ============" << std::endl;
 }
 
 std::string SanitizeToken(std::string token) {

src/filter.hpp

@@ -5,6 +5,11 @@
 #include <string>
 #include <vector>
 
+// C++ maps don't allow specifying default value
+struct DoubleDefaultedToHalf {
+    double value = 0.5;
+};
+
 struct ReportData {
     double spam_precision;
     double spam_recall;
@@ -33,7 +38,7 @@ public:
 
 private:
     double sentence_probability_ham = 0.5; // Spam is 1 - sentence_probability_ham 
-    std::map<std::string, double> probability_dictionary;
+    std::map<std::string, DoubleDefaultedToHalf> probability_dictionary;
     std::vector<SMSMessage> filtered_messages;
     ReportData GenerateReport(void);
     void PrintReport(ReportData report);