CMTutor - limit path finding algorithm search depth

TutoringModule/CollectiveModelTutor/ErrorPreventionMessages/Its.TutoringModule.CMTutor.EPM.PathFind/PathFinder.cs

@@ -30,14 +30,14 @@ public PathFinder(StudentActionsModel model)
         /// List of PathInfo objects that contain info about destination nodes that paths could be found to and
         /// maximum possible path confidence.
         /// </returns>
-        public List<PathInfo> Find(string fromNodeKey, HashSet<string> targetNodeKeys)
+        public List<PathInfo> Find(string fromNodeKey, HashSet<string> targetNodeKeys, int searchDepth)
         {
             // Init the finder                        
             PathInfo p = new PathInfo(fromNodeKey, fromNodeKey, 0, 1);
             Queue<PathInfo> toExplore = new Queue<PathInfo>();
             toExplore.Enqueue(p);
 
-            List<PathInfo> pathsToTargets = ExplorePaths(toExplore, targetNodeKeys);
+            List<PathInfo> pathsToTargets = ExplorePaths(toExplore, targetNodeKeys, searchDepth);
 
             return pathsToTargets;
         }
@@ -49,7 +49,7 @@ public List<PathInfo> Find(string fromNodeKey, HashSet<string> targetNodeKeys)
         /// <param name="targetNodeKeys"></param>
         /// <param name="pathConfThreshold"></param>
         /// <returns></returns>
-        private List<PathInfo> ExplorePaths(Queue<PathInfo> toExplore, HashSet<string> targetNodeKeys)
+        private List<PathInfo> ExplorePaths(Queue<PathInfo> toExplore, HashSet<string> targetNodeKeys, int searchDepth)
         {
             double allPathConfidenceSum = 1;
             List<PathInfo> pathsToTargets = new List<PathInfo>();
@@ -69,15 +69,23 @@ private List<PathInfo> ExplorePaths(Queue<PathInfo> toExplore, HashSet<string> t
                 // Create + enqueue PathInfo for all transitions
                 foreach (Arc<State, Event> transition in node.OutArcs.Values)
                 {
-                    if (pathInfo.Visited(transition.Key.ToString()))
-                    {
-                        continue;
-                    }
-                    else
+                    if (!pathInfo.Visited(transition.Key.ToString()))
                     {
                         string nextNodeKey = model.GetInStateKey(transition);
                         Node<State, Event> nextNode = model.GetState(nextNodeKey);
-                        int length = pathInfo.PathLength + 1;
+                        int length = pathInfo.PathLength;
+
+                        // Only count correct states to determine search depth (prevents depth inflation by multiple errors states attached to a single action)
+                        if (nextNode.Specification.GetType() == typeof(CorrectState))
+                        {
+                            length += 1;
+                        }
+
+                        if (length > searchDepth)
+                        {
+                            continue;
+                        }
+
                         double newPathConfidence = pathInfo.PathConfidence * model.GetEventConfidence(transition);
 
                         // Replace old path condifence with the sum of confidences of all child paths
@@ -119,11 +127,10 @@ public Dictionary<string, double> AddPathConfidenceByTarget(List<PathInfo> paths
         }
 
         public Dictionary<string, double> FindPathsAboveThreshold(string fromNodeKey, HashSet<string> targetNodeKeys,
-            double pathConfThreshold)
+            double pathConfThreshold, int searchDepth)
         {
             Dictionary<string, double> results = new Dictionary<string, double>();
-//            List<PathInfo> allPathsToTargets = Find(fromNodeKey, targetNodeKeys, pathConfThreshold);
-            List<PathInfo> allPathsToTargets = Find(fromNodeKey, targetNodeKeys);
+            List<PathInfo> allPathsToTargets = Find(fromNodeKey, targetNodeKeys, searchDepth);
             Dictionary<string, double> totalPathConfidencesByTarget = AddPathConfidenceByTarget(allPathsToTargets);
 
             foreach (string key in totalPathConfidencesByTarget.Keys)

TutoringModule/CollectiveModelTutor/Its.TutoringModule.CMTutor/CollectiveModelTutor.cs

@@ -149,7 +149,7 @@ private void GetRelevantErrorPreventionMessages(string actionName, string domain
 
             PathFinder pf = new PathFinder(sbpControl.GetStudentActionsModel(domainName, CLUSTER_METHOD, studentKey));
             Dictionary<string, double> reStatePathConfidences =
-                pf.FindPathsAboveThreshold(lastState.Key, reStateKeys, _config.NoErrorPreventionConfidenceThreshold);
+                pf.FindPathsAboveThreshold(lastState.Key, reStateKeys, _config.NoErrorPreventionConfidenceThreshold, _config.ErrorPreventionSearchDepthLimit);
 
             // Add messages of the right level of detail to the output container
             foreach (string targetStateKey in reStatePathConfidences.Keys)

TutoringModule/CollectiveModelTutor/Its.TutoringModule.CMTutorTest/ErrorPreventionMessageTest.cs

@@ -278,7 +278,7 @@ public void TestDomain1Graph1PathFinding()
             // Check probable errors from Initial State
             PathFinder pf = new PathFinder(sam);
             Dictionary<string, double> reStatePathConfidences =
-                pf.FindPathsAboveThreshold(initState.Key, reStateKeys, noErrorPreventionConfidenceThreshold);
+                pf.FindPathsAboveThreshold(initState.Key, reStateKeys, noErrorPreventionConfidenceThreshold, 10);
 
             Assert.AreEqual(2, reStatePathConfidences.Count);
             Assert.That(reStatePathConfidences["f0t4_f0t3_RelevantErrors"], Is.EqualTo(0.6).Within(Util.DOUBLE_PRECISION));
@@ -511,13 +511,13 @@ public void TestDomain1Graph2PathFinding()
             // Check probable errors from Initial State
             PathFinder pf = new PathFinder(sam);
             Dictionary<string, double> reStatePathConfidences =
-                pf.FindPathsAboveThreshold(initState.Key, reStateKeys, noErrorPreventionConfidenceThreshold);
+                pf.FindPathsAboveThreshold(initState.Key, reStateKeys, noErrorPreventionConfidenceThreshold, 10);
 
             Assert.AreEqual(1, reStatePathConfidences.Count);
             Assert.That(reStatePathConfidences["f0t4_f0t3_RelevantErrors"], Is.EqualTo(0.6).Within(Util.DOUBLE_PRECISION));
 
             // Check probable errors from f0t4_CorrectFlow
-            reStatePathConfidences = pf.FindPathsAboveThreshold("f0t4_CorrectFlow", reStateKeys, noErrorPreventionConfidenceThreshold);
+            reStatePathConfidences = pf.FindPathsAboveThreshold("f0t4_CorrectFlow", reStateKeys, noErrorPreventionConfidenceThreshold, 10);
 
             Assert.AreEqual(2, reStatePathConfidences.Count);
             Assert.That(reStatePathConfidences["f0t4_f0t3_RelevantErrors"], Is.EqualTo(1).Within(Util.DOUBLE_PRECISION));

TutoringModule/CollectiveModelTutor/Its.TutoringModule.CMTutorTest/Its.TutoringModule.CMTutorTest.dll.config

@@ -23,5 +23,6 @@
         <add key="MediumDetailErrorPreventionConfidenceThreshold" value="0.5"/>
         <add key="NoErrorPreventionIEConfidenceThreshold" value="0.5"/>
         <add key="NoErrorPreventionIERepetitionThreshold" value="0.5"/>
+        <add key="ErrorPreventionSearchDepthLimit" value="10"/>
     </appSettings>
 </configuration>

TutoringModule/ReactiveTutor/Its.TutoringModule.ReactiveTutorTest/Its.TutoringModule.ReactiveTutorTest.dll.config

@@ -23,5 +23,6 @@
         <add key="MediumDetailErrorPreventionConfidenceThreshold" value="0.5"/>
         <add key="NoErrorPreventionIEConfidenceThreshold" value="0.5"/>
         <add key="NoErrorPreventionIERepetitionThreshold" value="0.5"/>
+        <add key="ErrorPreventionSearchDepthLimit" value="10"/>
     </appSettings>
 </configuration>

Utils/Its.Utils.Config/DefaultTutorConfig.cs

@@ -27,6 +27,7 @@ public class DefaultTutorConfig : ITutorConfig
         private double mediumDetailErrorPreventionConfidenceThreshold;
         private double noErrorPreventionIEConfidenceThreshold;
         private double noErrorPreventionIERepetitionThreshold;
+        private int errorPreventionSearchDepthLimit;
 
         public int InitialColumn
         {
@@ -138,6 +139,11 @@ public double NoErrorPreventionIERepetitionThreshold
             get { return noErrorPreventionIERepetitionThreshold; }
         }
 
+        public int ErrorPreventionSearchDepthLimit
+        {
+            get { return errorPreventionSearchDepthLimit; }
+        }
+
         public DefaultTutorConfig()
         {
             InitFromSystemConfig();
@@ -178,6 +184,7 @@ private void InitFromSystemConfig()
             mediumDetailErrorPreventionConfidenceThreshold = double.Parse(ConfigurationManager.AppSettings["MediumDetailErrorPreventionConfidenceThreshold"]);
             noErrorPreventionIEConfidenceThreshold = double.Parse(ConfigurationManager.AppSettings["NoErrorPreventionIEConfidenceThreshold"]);
             noErrorPreventionIERepetitionThreshold = double.Parse(ConfigurationManager.AppSettings["NoErrorPreventionIERepetitionThreshold"]);
+            errorPreventionSearchDepthLimit = int.Parse(ConfigurationManager.AppSettings["ErrorPreventionSearchDepthLimit"]);
         }
 
         private void InitFromTutorConfig(ITutorConfig config)
@@ -204,6 +211,7 @@ private void InitFromTutorConfig(ITutorConfig config)
             mediumDetailErrorPreventionConfidenceThreshold = config.MediumDetailErrorPreventionConfidenceThreshold;
             noErrorPreventionIEConfidenceThreshold = config.NoErrorPreventionIEConfidenceThreshold;
             noErrorPreventionIERepetitionThreshold = config.NoErrorPreventionIERepetitionThreshold;
+            errorPreventionSearchDepthLimit = config.ErrorPreventionSearchDepthLimit;
         }
 
         private void InitFromDictionary(Dictionary<string, string> values)
@@ -230,6 +238,7 @@ private void InitFromDictionary(Dictionary<string, string> values)
             string mediumDetailErrorPreventionConfidenceThreshold;
             string noErrorPreventionIEConfidenceThreshold;
             string noErrorPreventionIERepetitionThreshold;
+            string errorPreventionSearchDepthLimit;
 
             if (values.TryGetValue("InitialColumn", out initialColumn))
             {
@@ -341,6 +350,11 @@ private void InitFromDictionary(Dictionary<string, string> values)
             {
                 this.noErrorPreventionIERepetitionThreshold = double.Parse(noErrorPreventionIERepetitionThreshold);
             }
+
+            if (values.TryGetValue("ErrorPreventionSearchDepthLimit", out errorPreventionSearchDepthLimit))
+            {
+                this.errorPreventionSearchDepthLimit = int.Parse(errorPreventionSearchDepthLimit);
+            }
         }
     }
 }

Utils/Its.Utils.Config/ITutorConfig.cs

@@ -25,5 +25,6 @@ public interface ITutorConfig
         double HighDetailErrorPreventionConfidenceThreshold { get; }
         double NoErrorPreventionIEConfidenceThreshold { get; }
         double NoErrorPreventionIERepetitionThreshold { get; }
+        int ErrorPreventionSearchDepthLimit { get; }
     }
 }