diff --git a/genomix/genomix-data/src/main/java/edu/uci/ics/genomix/type/KmerBytesWritable.java b/genomix/genomix-data/src/main/java/edu/uci/ics/genomix/type/KmerBytesWritable.java
index 4883176..78d8d85 100644
--- a/genomix/genomix-data/src/main/java/edu/uci/ics/genomix/type/KmerBytesWritable.java
+++ b/genomix/genomix-data/src/main/java/edu/uci/ics/genomix/type/KmerBytesWritable.java
@@ -317,7 +317,7 @@
             }
             bytes[offset] = (byte) (nextCode & 0x3);
         } else {
-            bytes[offset] = (byte) (bytes[offset] | ((nextCode & 0x3) << (((kmerlength-1) % 4) << 1)));
+            bytes[offset] = (byte) (bytes[offset] | ((nextCode & 0x3) << (((kmerlength - 1) % 4) << 1)));
         }
         clearLeadBit();
     }
diff --git a/genomix/genomix-data/src/main/java/edu/uci/ics/genomix/type/NodeWritable.java b/genomix/genomix-data/src/main/java/edu/uci/ics/genomix/type/NodeWritable.java
index 0276c3a..73612e2 100644
--- a/genomix/genomix-data/src/main/java/edu/uci/ics/genomix/type/NodeWritable.java
+++ b/genomix/genomix-data/src/main/java/edu/uci/ics/genomix/type/NodeWritable.java
@@ -16,8 +16,8 @@
     private PositionListWritable incomingList;
     private PositionListWritable outgoingList;
     private KmerBytesWritable kmer;
-    
-    public NodeWritable(){
+
+    public NodeWritable() {
         nodeID = new PositionWritable();
         incomingList = new PositionListWritable();
         outgoingList = new PositionListWritable();
@@ -47,6 +47,10 @@
         incomingList.set(incoming);
     }
 
+    public void setKmer(KmerBytesWritable kmer) {
+        this.kmer = kmer;
+    }
+
     public void setOutgoingList(PositionListWritable outgoing) {
         outgoingList.set(outgoing);
     }
@@ -111,9 +115,9 @@
     public int hashCode() {
         return nodeID.hashCode();
     }
-    
+
     @Override
-    public String toString(){
+    public String toString() {
         StringBuilder sbuilder = new StringBuilder();
         sbuilder.append('(');
         sbuilder.append(nodeID.toString()).append('\t');
diff --git a/genomix/genomix-data/src/main/java/edu/uci/ics/genomix/type/NoteWritableFactory.java b/genomix/genomix-data/src/main/java/edu/uci/ics/genomix/type/NoteWritableFactory.java
new file mode 100644
index 0000000..55c6ca7
--- /dev/null
+++ b/genomix/genomix-data/src/main/java/edu/uci/ics/genomix/type/NoteWritableFactory.java
@@ -0,0 +1,37 @@
+package edu.uci.ics.genomix.type;
+
+public class NoteWritableFactory {
+    private NodeWritable node;
+    private KmerBytesWritableFactory kmerBytesWritableFactory;
+    private int kmerSize = 55;
+
+    public NoteWritableFactory() {
+        node = new NodeWritable();
+        kmerBytesWritableFactory = new KmerBytesWritableFactory(kmerSize);
+    }
+
+    public NodeWritable append(final NodeWritable orignalNode, final KmerBytesWritable appendKmer){
+        KmerBytesWritable preKmer = orignalNode.getKmer();
+        node.setKmer(kmerBytesWritableFactory.mergeTwoKmer(preKmer,appendKmer));
+        return node;
+    }
+    
+    public NodeWritable append(final NodeWritable orignalNode, final NodeWritable appendNode) {
+        KmerBytesWritable nextKmer = kmerBytesWritableFactory.getSubKmerFromChain(kmerSize - 2, appendNode.getKmer().kmerlength - kmerSize + 2,
+                appendNode.getKmer());
+        return append(orignalNode, nextKmer);
+    }
+
+    public NodeWritable prepend(final NodeWritable orignalNode, final KmerBytesWritable prependKmer){
+        KmerBytesWritable nextKmer = orignalNode.getKmer();
+        node.setKmer(kmerBytesWritableFactory.mergeTwoKmer(prependKmer,nextKmer));
+        return node;
+    }
+    
+    public NodeWritable prepend(final NodeWritable orignalNode, final NodeWritable prependNode) {
+        KmerBytesWritable prependKmer = kmerBytesWritableFactory.getSubKmerFromChain(kmerSize - 2, orignalNode.getKmer().kmerlength - kmerSize + 2,
+                orignalNode.getKmer());
+        return prepend(orignalNode, prependKmer);
+    }
+
+}
diff --git a/genomix/genomix-data/src/main/java/edu/uci/ics/genomix/type/PositionWritable.java b/genomix/genomix-data/src/main/java/edu/uci/ics/genomix/type/PositionWritable.java
index c19af12..42ff47a 100644
--- a/genomix/genomix-data/src/main/java/edu/uci/ics/genomix/type/PositionWritable.java
+++ b/genomix/genomix-data/src/main/java/edu/uci/ics/genomix/type/PositionWritable.java
@@ -10,7 +10,7 @@
 
 import edu.uci.ics.genomix.data.Marshal;
 
-public class PositionWritable implements WritableComparable<PositionWritable> , Serializable{
+public class PositionWritable implements WritableComparable<PositionWritable>, Serializable {
     /**
      * 
      */
@@ -33,11 +33,15 @@
     public PositionWritable(byte[] storage, int offset) {
         setNewReference(storage, offset);
     }
-    
+
     public void setNewReference(byte[] storage, int offset) {
         this.storage = storage;
         this.offset = offset;
     }
+
+    public void set(PositionWritable pos) {
+        set(pos.getReadID(), pos.getPosInRead());
+    }
     
     public void set(int readID, byte posInRead) {
         Marshal.putInt(readID, storage, offset);
@@ -73,7 +77,7 @@
     public void write(DataOutput out) throws IOException {
         out.write(storage, offset, LENGTH);
     }
-    
+
     @Override
     public int hashCode() {
         return this.getReadID();
diff --git a/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/api/io/binary/BinaryVertexInputFormat.java b/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/api/io/binary/BinaryVertexInputFormat.java
index a4134af..636cf86 100644
--- a/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/api/io/binary/BinaryVertexInputFormat.java
+++ b/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/api/io/binary/BinaryVertexInputFormat.java
@@ -3,6 +3,7 @@
 import java.io.IOException;
 import java.util.List;
 
+import org.apache.hadoop.io.NullWritable;
 import org.apache.hadoop.io.Writable;
 import org.apache.hadoop.io.WritableComparable;
 import org.apache.hadoop.mapreduce.InputSplit;
@@ -13,8 +14,7 @@
 
 import edu.uci.ics.pregelix.api.io.VertexInputFormat;
 import edu.uci.ics.pregelix.api.io.VertexReader;
-import edu.uci.ics.genomix.type.KmerBytesWritable;
-import edu.uci.ics.genomix.type.KmerCountValue;
+import edu.uci.ics.genomix.type.NodeWritable;
 
 public class BinaryVertexInputFormat<I extends WritableComparable<?>, V extends Writable, E extends Writable, M extends Writable>
         extends VertexInputFormat<I, V, E, M> {
@@ -38,7 +38,7 @@
     public static abstract class BinaryVertexReader<I extends WritableComparable<?>, V extends Writable, E extends Writable, M extends Writable>
             implements VertexReader<I, V, E, M> {
         /** Internal line record reader */
-        private final RecordReader<KmerBytesWritable, KmerCountValue> lineRecordReader;
+        private final RecordReader<NodeWritable, NullWritable> lineRecordReader;
         /** Context passed to initialize */
         private TaskAttemptContext context;
 
@@ -48,7 +48,7 @@
          * @param recordReader
          *            Line record reader from SequenceFileInputFormat
          */
-        public BinaryVertexReader(RecordReader<KmerBytesWritable, KmerCountValue> recordReader) {
+        public BinaryVertexReader(RecordReader<NodeWritable, NullWritable> recordReader) {
             this.lineRecordReader = recordReader;
         }
 
@@ -74,7 +74,7 @@
          * 
          * @return Record reader to be used for reading.
          */
-        protected RecordReader<KmerBytesWritable, KmerCountValue> getRecordReader() {
+        protected RecordReader<NodeWritable, NullWritable> getRecordReader() {
             return lineRecordReader;
         }
 
diff --git a/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/api/io/binary/BinaryVertexOutputFormat.java b/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/api/io/binary/BinaryVertexOutputFormat.java
index d921b5e..8fbd1ce 100644
--- a/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/api/io/binary/BinaryVertexOutputFormat.java
+++ b/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/api/io/binary/BinaryVertexOutputFormat.java
@@ -11,7 +11,7 @@
 import org.apache.hadoop.mapreduce.lib.output.SequenceFileOutputFormat;
 
 import edu.uci.ics.genomix.pregelix.io.ValueStateWritable;
-import edu.uci.ics.genomix.type.KmerBytesWritable;
+import edu.uci.ics.genomix.type.PositionWritable;
 import edu.uci.ics.pregelix.api.io.VertexOutputFormat;
 import edu.uci.ics.pregelix.api.io.VertexWriter;
 
@@ -49,7 +49,7 @@
         /** Context passed to initialize */
         private TaskAttemptContext context;
         /** Internal line record writer */
-        private final RecordWriter<KmerBytesWritable, ValueStateWritable> lineRecordWriter;
+        private final RecordWriter<PositionWritable, ValueStateWritable> lineRecordWriter;
 
         /**
          * Initialize with the LineRecordWriter.
@@ -57,7 +57,7 @@
          * @param lineRecordWriter
          *            Line record writer from SequenceFileOutputFormat
          */
-        public BinaryVertexWriter(RecordWriter<KmerBytesWritable, ValueStateWritable> lineRecordWriter) {
+        public BinaryVertexWriter(RecordWriter<PositionWritable, ValueStateWritable> lineRecordWriter) {
             this.lineRecordWriter = lineRecordWriter;
         }
 
@@ -76,7 +76,7 @@
          * 
          * @return Record writer to be used for writing.
          */
-        public RecordWriter<KmerBytesWritable, ValueStateWritable> getRecordWriter() {
+        public RecordWriter<PositionWritable, ValueStateWritable> getRecordWriter() {
             return lineRecordWriter;
         }
 
diff --git a/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/client/Client.java b/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/client/Client.java
index 438c99d..94b0c51 100644
--- a/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/client/Client.java
+++ b/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/client/Client.java
@@ -76,7 +76,7 @@
         }
         
         if (options.pseudoRate > 0 && options.pseudoRate <= 1)
-            job.getConfiguration().setFloat(P3ForPathMergeVertex.PSEUDORATE, options.pseudoRate);
+           job.getConfiguration().setFloat(P3ForPathMergeVertex.PSEUDORATE, options.pseudoRate);
         if (options.maxRound > 0)
             job.getConfiguration().setInt(P3ForPathMergeVertex.MAXROUND, options.maxRound);
         return options;
diff --git a/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/format/LogAlgorithmForPathMergeInputFormat.java b/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/format/LogAlgorithmForPathMergeInputFormat.java
index 4a76ff6..3fe04ff 100644
--- a/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/format/LogAlgorithmForPathMergeInputFormat.java
+++ b/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/format/LogAlgorithmForPathMergeInputFormat.java
@@ -8,35 +8,36 @@
 import org.apache.hadoop.mapreduce.TaskAttemptContext;
 
 import edu.uci.ics.genomix.pregelix.api.io.binary.BinaryVertexInputFormat;
-import edu.uci.ics.genomix.pregelix.io.LogAlgorithmMessageWritable;
+import edu.uci.ics.genomix.pregelix.io.MessageWritable;
 import edu.uci.ics.genomix.pregelix.io.ValueStateWritable;
 import edu.uci.ics.genomix.pregelix.type.State;
-import edu.uci.ics.genomix.type.KmerBytesWritable;
-import edu.uci.ics.genomix.type.KmerCountValue;
+import edu.uci.ics.genomix.type.NodeWritable;
+import edu.uci.ics.genomix.type.PositionWritable;
 import edu.uci.ics.pregelix.api.graph.Vertex;
 import edu.uci.ics.pregelix.api.io.VertexReader;
 import edu.uci.ics.pregelix.api.util.BspUtils;
 
 public class LogAlgorithmForPathMergeInputFormat extends
-        BinaryVertexInputFormat<KmerBytesWritable, ValueStateWritable, NullWritable, LogAlgorithmMessageWritable> {
+        BinaryVertexInputFormat<PositionWritable, ValueStateWritable, NullWritable, MessageWritable> {
     /**
      * Format INPUT
      */
     @SuppressWarnings("unchecked")
     @Override
-    public VertexReader<KmerBytesWritable, ValueStateWritable, NullWritable, LogAlgorithmMessageWritable> createVertexReader(
+    public VertexReader<PositionWritable, ValueStateWritable, NullWritable, MessageWritable> createVertexReader(
             InputSplit split, TaskAttemptContext context) throws IOException {
         return new BinaryLoadGraphReader(binaryInputFormat.createRecordReader(split, context));
     }
 
     @SuppressWarnings("rawtypes")
     class BinaryLoadGraphReader extends
-            BinaryVertexReader<KmerBytesWritable, ValueStateWritable, NullWritable, LogAlgorithmMessageWritable> {
+            BinaryVertexReader<PositionWritable, ValueStateWritable, NullWritable, MessageWritable> {
         private Vertex vertex = null;
-        private KmerBytesWritable vertexId = null;
+        private NodeWritable node = new NodeWritable();
+        private PositionWritable vertexId = new PositionWritable(); 
         private ValueStateWritable vertexValue = new ValueStateWritable();
 
-        public BinaryLoadGraphReader(RecordReader<KmerBytesWritable, KmerCountValue> recordReader) {
+        public BinaryLoadGraphReader(RecordReader<NodeWritable, NullWritable> recordReader) {
             super(recordReader);
         }
 
@@ -47,7 +48,7 @@
 
         @SuppressWarnings("unchecked")
         @Override
-        public Vertex<KmerBytesWritable, ValueStateWritable, NullWritable, LogAlgorithmMessageWritable> getCurrentVertex()
+        public Vertex<PositionWritable, ValueStateWritable, NullWritable, MessageWritable> getCurrentVertex()
                 throws IOException, InterruptedException {
             if (vertex == null)
                 vertex = (Vertex) BspUtils.createVertex(getContext().getConfiguration());
@@ -59,15 +60,15 @@
                 /**
                  * set the src vertex id
                  */
-                if (vertexId == null)
-                    vertexId = new KmerBytesWritable(getRecordReader().getCurrentKey().getKmerLength());
-                vertexId.set(getRecordReader().getCurrentKey());
+                node = getRecordReader().getCurrentKey();
+                vertexId.set(node.getNodeID());
                 vertex.setVertexId(vertexId);
                 /**
                  * set the vertex value
                  */
-                KmerCountValue kmerCountValue = getRecordReader().getCurrentValue();
-                vertexValue.setAdjMap(kmerCountValue.getAdjBitMap());
+                vertexValue.setIncomingList(node.getIncomingList());
+                vertexValue.setOutgoingList(node.getOutgoingList());
+                vertexValue.setMergeChain(node.getKmer());
                 vertexValue.setState(State.NON_VERTEX);
                 vertex.setVertexValue(vertexValue);
             }
diff --git a/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/format/LogAlgorithmForPathMergeOutputFormat.java b/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/format/LogAlgorithmForPathMergeOutputFormat.java
index 110247e..8a04292 100644
--- a/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/format/LogAlgorithmForPathMergeOutputFormat.java
+++ b/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/format/LogAlgorithmForPathMergeOutputFormat.java
@@ -11,16 +11,16 @@
 import edu.uci.ics.pregelix.api.io.VertexWriter;
 import edu.uci.ics.genomix.pregelix.io.ValueStateWritable;
 import edu.uci.ics.genomix.pregelix.type.State;
-import edu.uci.ics.genomix.type.KmerBytesWritable;
+import edu.uci.ics.genomix.type.PositionWritable;
 
 public class LogAlgorithmForPathMergeOutputFormat extends
-        BinaryVertexOutputFormat<KmerBytesWritable, ValueStateWritable, NullWritable> {
+        BinaryVertexOutputFormat<PositionWritable, ValueStateWritable, NullWritable> {
 
     @Override
-    public VertexWriter<KmerBytesWritable, ValueStateWritable, NullWritable> createVertexWriter(
+    public VertexWriter<PositionWritable, ValueStateWritable, NullWritable> createVertexWriter(
             TaskAttemptContext context) throws IOException, InterruptedException {
         @SuppressWarnings("unchecked")
-        RecordWriter<KmerBytesWritable, ValueStateWritable> recordWriter = binaryOutputFormat.getRecordWriter(context);
+        RecordWriter<PositionWritable, ValueStateWritable> recordWriter = binaryOutputFormat.getRecordWriter(context);
         return new BinaryLoadGraphVertexWriter(recordWriter);
     }
 
@@ -28,20 +28,18 @@
      * Simple VertexWriter that supports {@link BinaryLoadGraphVertex}
      */
     public static class BinaryLoadGraphVertexWriter extends
-            BinaryVertexWriter<KmerBytesWritable, ValueStateWritable, NullWritable> {
+            BinaryVertexWriter<PositionWritable, ValueStateWritable, NullWritable> {
 
-        public BinaryLoadGraphVertexWriter(RecordWriter<KmerBytesWritable, ValueStateWritable> lineRecordWriter) {
+        public BinaryLoadGraphVertexWriter(RecordWriter<PositionWritable, ValueStateWritable> lineRecordWriter) {
             super(lineRecordWriter);
         }
 
         @Override
-        public void writeVertex(Vertex<KmerBytesWritable, ValueStateWritable, NullWritable, ?> vertex)
+        public void writeVertex(Vertex<PositionWritable, ValueStateWritable, NullWritable, ?> vertex)
                 throws IOException, InterruptedException {
-            //&& vertex.getVertexValue().getState() != State.MID_VERTEX
             if (vertex.getVertexValue().getState() != State.END_VERTEX) {
                 getRecordWriter().write(vertex.getVertexId(), vertex.getVertexValue());
             }
-
         }
     }
 }
diff --git a/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/format/NaiveAlgorithmForPathMergeInputFormat.java b/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/format/NaiveAlgorithmForPathMergeInputFormat.java
index 8abfcd0..4011838 100644
--- a/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/format/NaiveAlgorithmForPathMergeInputFormat.java
+++ b/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/format/NaiveAlgorithmForPathMergeInputFormat.java
@@ -7,24 +7,25 @@
 import org.apache.hadoop.mapreduce.RecordReader;
 import org.apache.hadoop.mapreduce.TaskAttemptContext;
 
-import edu.uci.ics.genomix.type.KmerBytesWritable;
-import edu.uci.ics.genomix.type.KmerCountValue;
+import edu.uci.ics.genomix.type.NodeWritable;
+import edu.uci.ics.genomix.type.PositionWritable;
 import edu.uci.ics.pregelix.api.graph.Vertex;
 import edu.uci.ics.pregelix.api.io.VertexReader;
 import edu.uci.ics.pregelix.api.util.BspUtils;
-import edu.uci.ics.genomix.pregelix.io.NaiveAlgorithmMessageWritable;
+import edu.uci.ics.genomix.pregelix.io.MessageWritable;
 import edu.uci.ics.genomix.pregelix.io.ValueStateWritable;
+import edu.uci.ics.genomix.pregelix.type.State;
 import edu.uci.ics.genomix.pregelix.api.io.binary.BinaryVertexInputFormat;
 import edu.uci.ics.genomix.pregelix.api.io.binary.BinaryVertexInputFormat.BinaryVertexReader;
 
 public class NaiveAlgorithmForPathMergeInputFormat extends
-        BinaryVertexInputFormat<KmerBytesWritable, ValueStateWritable, NullWritable, NaiveAlgorithmMessageWritable> {
+        BinaryVertexInputFormat<PositionWritable, ValueStateWritable, NullWritable, MessageWritable> {
     /**
      * Format INPUT
      */
     @SuppressWarnings("unchecked")
     @Override
-    public VertexReader<KmerBytesWritable, ValueStateWritable, NullWritable, NaiveAlgorithmMessageWritable> createVertexReader(
+    public VertexReader<PositionWritable, ValueStateWritable, NullWritable, MessageWritable> createVertexReader(
             InputSplit split, TaskAttemptContext context) throws IOException {
         return new BinaryLoadGraphReader(binaryInputFormat.createRecordReader(split, context));
     }
@@ -32,12 +33,13 @@
 
 @SuppressWarnings("rawtypes")
 class BinaryLoadGraphReader extends
-        BinaryVertexReader<KmerBytesWritable, ValueStateWritable, NullWritable, NaiveAlgorithmMessageWritable> {
+        BinaryVertexReader<PositionWritable, ValueStateWritable, NullWritable, MessageWritable> {
     private Vertex vertex;
-    private KmerBytesWritable vertexId = null;
+    private NodeWritable node = new NodeWritable();
+    private PositionWritable vertexId = new PositionWritable();
     private ValueStateWritable vertexValue = new ValueStateWritable();
 
-    public BinaryLoadGraphReader(RecordReader<KmerBytesWritable, KmerCountValue> recordReader) {
+    public BinaryLoadGraphReader(RecordReader<NodeWritable, NullWritable> recordReader) {
         super(recordReader);
     }
 
@@ -48,7 +50,7 @@
 
     @SuppressWarnings("unchecked")
     @Override
-    public Vertex<KmerBytesWritable, ValueStateWritable, NullWritable, NaiveAlgorithmMessageWritable> getCurrentVertex()
+    public Vertex<PositionWritable, ValueStateWritable, NullWritable, MessageWritable> getCurrentVertex()
             throws IOException, InterruptedException {
         if (vertex == null)
             vertex = (Vertex) BspUtils.createVertex(getContext().getConfiguration());
@@ -61,15 +63,16 @@
             /**
              * set the src vertex id
              */
-            if (vertexId == null)
-                vertexId = new KmerBytesWritable(getRecordReader().getCurrentKey().getKmerLength());
-            vertexId.set(getRecordReader().getCurrentKey());
+            node = getRecordReader().getCurrentKey();
+            vertexId.set(node.getNodeID());
             vertex.setVertexId(vertexId);
             /**
              * set the vertex value
              */
-            KmerCountValue kmerCountValue = getRecordReader().getCurrentValue();
-            vertexValue.setAdjMap(kmerCountValue.getAdjBitMap());
+            vertexValue.setIncomingList(node.getIncomingList());
+            vertexValue.setOutgoingList(node.getOutgoingList());
+            vertexValue.setMergeChain(node.getKmer());
+            vertexValue.setState(State.NON_VERTEX);
             vertex.setVertexValue(vertexValue);
         }
 
diff --git a/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/format/NaiveAlgorithmForPathMergeOutputFormat.java b/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/format/NaiveAlgorithmForPathMergeOutputFormat.java
index 311283d..fe3b12d 100644
--- a/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/format/NaiveAlgorithmForPathMergeOutputFormat.java
+++ b/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/format/NaiveAlgorithmForPathMergeOutputFormat.java
@@ -8,18 +8,18 @@
 
 import edu.uci.ics.genomix.pregelix.api.io.binary.BinaryVertexOutputFormat;
 import edu.uci.ics.genomix.pregelix.io.ValueStateWritable;
-import edu.uci.ics.genomix.type.KmerBytesWritable;
+import edu.uci.ics.genomix.type.PositionWritable;
 import edu.uci.ics.pregelix.api.graph.Vertex;
 import edu.uci.ics.pregelix.api.io.VertexWriter;
 
 public class NaiveAlgorithmForPathMergeOutputFormat extends
-        BinaryVertexOutputFormat<KmerBytesWritable, ValueStateWritable, NullWritable> {
+        BinaryVertexOutputFormat<PositionWritable, ValueStateWritable, NullWritable> {
 
     @Override
-    public VertexWriter<KmerBytesWritable, ValueStateWritable, NullWritable> createVertexWriter(
+    public VertexWriter<PositionWritable, ValueStateWritable, NullWritable> createVertexWriter(
             TaskAttemptContext context) throws IOException, InterruptedException {
         @SuppressWarnings("unchecked")
-        RecordWriter<KmerBytesWritable, ValueStateWritable> recordWriter = binaryOutputFormat.getRecordWriter(context);
+        RecordWriter<PositionWritable, ValueStateWritable> recordWriter = binaryOutputFormat.getRecordWriter(context);
         return new BinaryLoadGraphVertexWriter(recordWriter);
     }
 
@@ -27,16 +27,14 @@
      * Simple VertexWriter that supports {@link BinaryLoadGraphVertex}
      */
     public static class BinaryLoadGraphVertexWriter extends
-            BinaryVertexWriter<KmerBytesWritable, ValueStateWritable, NullWritable> {
-        public BinaryLoadGraphVertexWriter(RecordWriter<KmerBytesWritable, ValueStateWritable> lineRecordWriter) {
+            BinaryVertexWriter<PositionWritable, ValueStateWritable, NullWritable> {
+        public BinaryLoadGraphVertexWriter(RecordWriter<PositionWritable, ValueStateWritable> lineRecordWriter) {
             super(lineRecordWriter);
         }
 
         @Override
-        public void writeVertex(Vertex<KmerBytesWritable, ValueStateWritable, NullWritable, ?> vertex)
+        public void writeVertex(Vertex<PositionWritable, ValueStateWritable, NullWritable, ?> vertex)
                 throws IOException, InterruptedException {
-            //if(vertex.getVertexValue().getState() == State.FILTER
-            //		|| vertex.getVertexValue().getState() == State.FINAL_VERTEX)
             getRecordWriter().write(vertex.getVertexId(), vertex.getVertexValue());
         }
     }
diff --git a/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/io/LogAlgorithmMessageWritable.java b/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/io/LogAlgorithmMessageWritable.java
deleted file mode 100644
index fc57b74..0000000
--- a/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/io/LogAlgorithmMessageWritable.java
+++ /dev/null
@@ -1,153 +0,0 @@
-package edu.uci.ics.genomix.pregelix.io;
-
-import java.io.DataInput;
-import java.io.DataOutput;
-import java.io.IOException;
-
-import org.apache.hadoop.io.WritableComparable;
-
-import edu.uci.ics.genomix.pregelix.operator.LogAlgorithmForPathMergeVertex;
-import edu.uci.ics.genomix.pregelix.type.CheckMessage;
-import edu.uci.ics.genomix.type.KmerBytesWritable;
-import edu.uci.ics.genomix.type.VKmerBytesWritable;
-
-public class LogAlgorithmMessageWritable implements WritableComparable<LogAlgorithmMessageWritable> {
-    /**
-     * sourceVertexId stores source vertexId when headVertex sends the message
-     * stores neighber vertexValue when pathVertex sends the message
-     * chainVertexId stores the chains of connected DNA
-     * file stores the point to the file that stores the chains of connected DNA
-     */
-    private KmerBytesWritable sourceVertexId;
-    private VKmerBytesWritable chainVertexId;
-    private byte adjMap;
-    private byte message;
-
-    private byte checkMessage;
-
-    public LogAlgorithmMessageWritable() {
-        sourceVertexId = new VKmerBytesWritable(LogAlgorithmForPathMergeVertex.kmerSize);
-        chainVertexId = new VKmerBytesWritable(LogAlgorithmForPathMergeVertex.kmerSize);
-        adjMap = 0;
-        message = 0;
-        checkMessage = 0;
-    }
-
-    public void set(KmerBytesWritable sourceVertexId, VKmerBytesWritable chainVertexId, byte adjMap, byte message) {
-        checkMessage = 0;
-        if (sourceVertexId != null) {
-            checkMessage |= CheckMessage.SOURCE;
-            this.sourceVertexId.set(sourceVertexId);
-        }
-        if (chainVertexId != null) {
-            checkMessage |= CheckMessage.CHAIN;
-            this.chainVertexId.set(chainVertexId);
-        }
-        if (adjMap != 0) {
-            checkMessage |= CheckMessage.ADJMAP;
-            this.adjMap = adjMap;
-        }
-        this.message = message;
-    }
-
-    public void reset() {
-        checkMessage = 0;
-        chainVertexId.reset(LogAlgorithmForPathMergeVertex.kmerSize);
-        adjMap = (byte) 0;
-        message = 0;
-    }
-
-    public KmerBytesWritable getSourceVertexId() {
-        return sourceVertexId;
-    }
-
-    public void setSourceVertexId(KmerBytesWritable sourceVertexId) {
-        if (sourceVertexId != null) {
-            checkMessage |= CheckMessage.SOURCE;
-            this.sourceVertexId.set(sourceVertexId);
-        }
-    }
-
-    public byte getAdjMap() {
-        return adjMap;
-    }
-
-    public void setAdjMap(byte adjMap) {
-        if (adjMap != 0) {
-            checkMessage |= CheckMessage.ADJMAP;
-            this.adjMap = adjMap;
-        }
-    }
-
-    public VKmerBytesWritable getChainVertexId() {
-        return chainVertexId;
-    }
-
-    public void setChainVertexId(VKmerBytesWritable chainVertexId) {
-        if (chainVertexId != null) {
-            checkMessage |= CheckMessage.CHAIN;
-            this.chainVertexId.set(chainVertexId);
-        }
-    }
-
-    public byte getMessage() {
-        return message;
-    }
-
-    public void setMessage(byte message) {
-        this.message = message;
-    }
-
-    public int getLengthOfChain() {
-        return chainVertexId.getKmerLength();
-    }
-
-    @Override
-    public void write(DataOutput out) throws IOException {
-        out.writeByte(checkMessage);
-        if ((checkMessage & CheckMessage.SOURCE) != 0)
-            sourceVertexId.write(out);
-        if ((checkMessage & CheckMessage.CHAIN) != 0)
-            chainVertexId.write(out);
-        if ((checkMessage & CheckMessage.ADJMAP) != 0)
-            out.write(adjMap);
-        out.writeByte(message);
-    }
-
-    @Override
-    public void readFields(DataInput in) throws IOException {
-        this.reset();
-        checkMessage = in.readByte();
-        if ((checkMessage & CheckMessage.SOURCE) != 0)
-            sourceVertexId.readFields(in);
-        if ((checkMessage & CheckMessage.CHAIN) != 0)
-            chainVertexId.readFields(in);
-        if ((checkMessage & CheckMessage.ADJMAP) != 0)
-            adjMap = in.readByte();
-        message = in.readByte();
-    }
-
-    @Override
-    public int hashCode() {
-        return chainVertexId.hashCode();
-    }
-
-    @Override
-    public boolean equals(Object o) {
-        if (o instanceof LogAlgorithmMessageWritable) {
-            LogAlgorithmMessageWritable tp = (LogAlgorithmMessageWritable) o;
-            return chainVertexId.equals(tp.chainVertexId);
-        }
-        return false;
-    }
-
-    @Override
-    public String toString() {
-        return chainVertexId.toString();
-    }
-
-    @Override
-    public int compareTo(LogAlgorithmMessageWritable tp) {
-        return chainVertexId.compareTo(tp.chainVertexId);
-    }
-}
diff --git a/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/io/MessageWritable.java b/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/io/MessageWritable.java
new file mode 100644
index 0000000..31d313d
--- /dev/null
+++ b/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/io/MessageWritable.java
@@ -0,0 +1,153 @@
+package edu.uci.ics.genomix.pregelix.io;
+
+import java.io.DataInput;
+import java.io.DataOutput;
+import java.io.IOException;
+
+import org.apache.hadoop.io.WritableComparable;
+
+import edu.uci.ics.genomix.pregelix.type.CheckMessage;
+import edu.uci.ics.genomix.pregelix.type.Message;
+import edu.uci.ics.genomix.type.KmerBytesWritable;
+import edu.uci.ics.genomix.type.PositionListWritable;
+import edu.uci.ics.genomix.type.PositionWritable;
+
+public class MessageWritable implements WritableComparable<MessageWritable> {
+    /**
+     * sourceVertexId stores source vertexId when headVertex sends the message
+     * stores neighber vertexValue when pathVertex sends the message
+     * file stores the point to the file that stores the chains of connected DNA
+     */
+    private PositionWritable sourceVertexId;
+    private KmerBytesWritable chainVertexId;
+    private PositionListWritable neighberNode; //incoming or outgoing
+    private byte message;
+
+    private byte checkMessage;
+
+    public MessageWritable() {
+        sourceVertexId = new PositionWritable();
+        chainVertexId = new KmerBytesWritable(0);
+        neighberNode = new PositionListWritable();
+        message = Message.NON;
+        checkMessage = (byte) 0;
+    }
+
+    public void set(PositionWritable sourceVertexId, KmerBytesWritable chainVertexId, PositionListWritable neighberNode, byte message) {
+        checkMessage = 0;
+        if (sourceVertexId != null) {
+            checkMessage |= CheckMessage.SOURCE;
+            this.sourceVertexId.set(sourceVertexId.getReadID(),sourceVertexId.getPosInRead());
+        }
+        if (chainVertexId != null) {
+            checkMessage |= CheckMessage.CHAIN;
+            this.chainVertexId.set(chainVertexId);
+        }
+        if (neighberNode != null) {
+            checkMessage |= CheckMessage.NEIGHBER;
+            this.neighberNode.set(neighberNode);
+        }
+        this.message = message;
+    }
+
+    public void reset() {
+        checkMessage = 0;
+        chainVertexId.reset(1);
+        neighberNode.reset();
+        message = Message.NON;
+    }
+
+    public PositionWritable getSourceVertexId() {
+        return sourceVertexId;
+    }
+
+    public void setSourceVertexId(PositionWritable sourceVertexId) {
+        if (sourceVertexId != null) {
+            checkMessage |= CheckMessage.SOURCE;
+            this.sourceVertexId.set(sourceVertexId.getReadID(),sourceVertexId.getPosInRead());
+        }
+    }
+    
+    public KmerBytesWritable getChainVertexId() {
+        return chainVertexId;
+    }
+
+    public void setChainVertexId(KmerBytesWritable chainVertexId) {
+        if (chainVertexId != null) {
+            checkMessage |= CheckMessage.CHAIN;
+            this.chainVertexId.set(chainVertexId);
+        }
+    }
+    
+    public PositionListWritable getNeighberNode() {
+        return neighberNode;
+    }
+
+    public void setNeighberNode(PositionListWritable neighberNode) {
+        if(neighberNode != null){
+            checkMessage |= CheckMessage.NEIGHBER;
+            this.neighberNode.set(neighberNode);
+        }
+    }
+    
+    public int getLengthOfChain() {
+        return chainVertexId.getKmerLength();
+    }
+
+    public byte getMessage() {
+        return message;
+    }
+
+    public void setMessage(byte message) {
+        this.message = message;
+    }
+
+    @Override
+    public void write(DataOutput out) throws IOException {
+        out.writeByte(checkMessage);
+        if ((checkMessage & CheckMessage.SOURCE) != 0)
+            sourceVertexId.write(out);
+        if ((checkMessage & CheckMessage.CHAIN) != 0)
+            chainVertexId.write(out);
+        if ((checkMessage & CheckMessage.NEIGHBER) != 0)
+            neighberNode.write(out);
+        out.write(message);
+    }
+
+    @Override
+    public void readFields(DataInput in) throws IOException {
+        this.reset();
+        checkMessage = in.readByte();
+        if ((checkMessage & CheckMessage.SOURCE) != 0)
+            sourceVertexId.readFields(in);
+        if ((checkMessage & CheckMessage.CHAIN) != 0)
+            chainVertexId.readFields(in);
+        if ((checkMessage & CheckMessage.NEIGHBER) != 0)
+            neighberNode.readFields(in);
+        message = in.readByte();
+    }
+
+    @Override
+    public int hashCode() {
+        return sourceVertexId.hashCode();
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (o instanceof MessageWritable) {
+            MessageWritable tp = (MessageWritable) o;
+            return sourceVertexId.equals(tp.sourceVertexId);
+        }
+        return false;
+    }
+
+    @Override
+    public String toString() {
+        return sourceVertexId.toString();
+    }
+
+    @Override
+    public int compareTo(MessageWritable tp) {
+        return sourceVertexId.compareTo(tp.sourceVertexId);
+    }
+}
diff --git a/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/io/NaiveAlgorithmMessageWritable.java b/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/io/NaiveAlgorithmMessageWritable.java
deleted file mode 100644
index c5378a2..0000000
--- a/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/io/NaiveAlgorithmMessageWritable.java
+++ /dev/null
@@ -1,179 +0,0 @@
-package edu.uci.ics.genomix.pregelix.io;
-
-import java.io.DataInput;
-import java.io.DataOutput;
-import java.io.IOException;
-
-import org.apache.hadoop.io.WritableComparable;
-
-import edu.uci.ics.genomix.pregelix.operator.NaiveAlgorithmForPathMergeVertex;
-import edu.uci.ics.genomix.pregelix.type.CheckMessage;
-import edu.uci.ics.genomix.pregelix.type.Message;
-import edu.uci.ics.genomix.type.KmerBytesWritable;
-import edu.uci.ics.genomix.type.VKmerBytesWritable;
-
-public class NaiveAlgorithmMessageWritable implements WritableComparable<NaiveAlgorithmMessageWritable> {
-    /**
-     * sourceVertexId stores source vertexId when headVertex sends the message
-     * stores neighber vertexValue when pathVertex sends the message
-     * file stores the point to the file that stores the chains of connected DNA
-     */
-    private KmerBytesWritable sourceVertexId;
-    private byte adjMap;
-    private byte lastGeneCode;
-    private VKmerBytesWritable chainVertexId;
-    private byte message;
-
-    private byte checkMessage;
-
-    public NaiveAlgorithmMessageWritable() {
-        sourceVertexId = new VKmerBytesWritable(NaiveAlgorithmForPathMergeVertex.kmerSize);
-        chainVertexId = new VKmerBytesWritable(1);
-        adjMap = (byte) 0;
-        lastGeneCode = (byte) -1;
-        message = Message.NON;
-        checkMessage = (byte) 0;
-    }
-
-    public void set(KmerBytesWritable sourceVertex, byte adjMap, byte lastGeneCode, VKmerBytesWritable chainVertexId, byte message) {
-        checkMessage = 0;
-        if (sourceVertexId != null) {
-            checkMessage |= CheckMessage.SOURCE;
-            this.sourceVertexId.set(sourceVertexId);
-        }
-        if (adjMap != 0) {
-            checkMessage |= CheckMessage.ADJMAP;
-            this.adjMap = adjMap;
-        }
-        if (lastGeneCode != 0) {
-            checkMessage |= CheckMessage.LASTGENECODE;
-            this.lastGeneCode = lastGeneCode;
-        }
-        if (chainVertexId != null) {
-            checkMessage |= CheckMessage.CHAIN;
-            this.chainVertexId.set(chainVertexId);
-        }
-        this.message = message;
-    }
-
-    public void reset() {
-        checkMessage = 0;
-        adjMap = (byte) 0;
-        lastGeneCode = (byte) -1;
-        chainVertexId.reset(1);
-        message = Message.NON;
-    }
-
-    public KmerBytesWritable getSourceVertexId() {
-        return sourceVertexId;
-    }
-
-    public void setSourceVertexId(KmerBytesWritable sourceVertexId) {
-        if (sourceVertexId != null) {
-            checkMessage |= CheckMessage.SOURCE;
-            this.sourceVertexId.set(sourceVertexId);
-        }
-    }
-
-    public byte getAdjMap() {
-        return adjMap;
-    }
-
-    public void setAdjMap(byte adjMap) {
-        if (adjMap != 0) {
-            checkMessage |= CheckMessage.ADJMAP;
-            this.adjMap = adjMap;
-        }
-    }
-
-    public byte getLastGeneCode() {
-        return lastGeneCode;
-    }
-
-    public void setLastGeneCode(byte lastGeneCode) {
-        if (lastGeneCode != -1) {
-            checkMessage |= CheckMessage.LASTGENECODE;
-            this.lastGeneCode = lastGeneCode;
-        }
-    }
-
-    public VKmerBytesWritable getChainVertexId() {
-        return chainVertexId;
-    }
-
-    public void setChainVertexId(VKmerBytesWritable chainVertexId) {
-        if (chainVertexId != null) {
-            checkMessage |= CheckMessage.CHAIN;
-            this.chainVertexId.set(chainVertexId);
-        }
-    }
-    
-    public int getLengthOfChain() {
-        return chainVertexId.getKmerLength();
-    }
-
-    public byte getMessage() {
-        return message;
-    }
-
-    public void setMessage(byte message) {
-        this.message = message;
-    }
-
-    public boolean isGeneCode(){
-        return ((checkMessage & CheckMessage.LASTGENECODE) != 0); 
-    }
-    
-    @Override
-    public void write(DataOutput out) throws IOException {
-        out.writeByte(checkMessage);
-        if ((checkMessage & CheckMessage.SOURCE) != 0)
-            sourceVertexId.write(out);
-        if ((checkMessage & CheckMessage.ADJMAP) != 0)
-            out.write(adjMap);
-        if ((checkMessage & CheckMessage.LASTGENECODE) != 0)
-            out.write(lastGeneCode);
-        if ((checkMessage & CheckMessage.CHAIN) != 0)
-            chainVertexId.write(out);
-        out.write(message);
-    }
-
-    @Override
-    public void readFields(DataInput in) throws IOException {
-        this.reset();
-        checkMessage = in.readByte();
-        if ((checkMessage & CheckMessage.SOURCE) != 0)
-            sourceVertexId.readFields(in);
-        if ((checkMessage & CheckMessage.ADJMAP) != 0)
-            adjMap = in.readByte();
-        if ((checkMessage & CheckMessage.LASTGENECODE) != 0)
-            lastGeneCode = in.readByte();
-        if ((checkMessage & CheckMessage.CHAIN) != 0)
-            chainVertexId.readFields(in);
-        message = in.readByte();
-    }
-
-    @Override
-    public int hashCode() {
-        return sourceVertexId.hashCode();
-    }
-
-    @Override
-    public boolean equals(Object o) {
-        if (o instanceof NaiveAlgorithmMessageWritable) {
-            NaiveAlgorithmMessageWritable tp = (NaiveAlgorithmMessageWritable) o;
-            return sourceVertexId.equals(tp.sourceVertexId);
-        }
-        return false;
-    }
-
-    @Override
-    public String toString() {
-        return sourceVertexId.toString();
-    }
-
-    @Override
-    public int compareTo(NaiveAlgorithmMessageWritable tp) {
-        return sourceVertexId.compareTo(tp.sourceVertexId);
-    }
-}
diff --git a/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/io/ValueStateWritable.java b/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/io/ValueStateWritable.java
index 9a9e30f..2554c8e 100644
--- a/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/io/ValueStateWritable.java
+++ b/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/io/ValueStateWritable.java
@@ -5,40 +5,50 @@
 import org.apache.hadoop.io.WritableComparable;
 
 import edu.uci.ics.genomix.pregelix.type.State;
-import edu.uci.ics.genomix.type.GeneCode;
 import edu.uci.ics.genomix.type.KmerBytesWritable;
-import edu.uci.ics.genomix.type.VKmerBytesWritable;
+import edu.uci.ics.genomix.type.PositionListWritable;
 
 public class ValueStateWritable implements WritableComparable<ValueStateWritable> {
 
-    private byte adjMap;
+    private PositionListWritable incomingList;
+    private PositionListWritable outgoingList;
     private byte state;
-    private VKmerBytesWritable mergeChain;
+    private KmerBytesWritable mergeChain;
 
     public ValueStateWritable() {
+        incomingList = new PositionListWritable();
+        outgoingList = new PositionListWritable();
         state = State.NON_VERTEX;
-        mergeChain = new VKmerBytesWritable(0);
-        //isOp = false;
+        mergeChain = new KmerBytesWritable(0);
     }
 
-    public ValueStateWritable(byte adjMap, byte state, VKmerBytesWritable mergeChain) {
-        this.adjMap = adjMap;
+    public ValueStateWritable(PositionListWritable incomingList, PositionListWritable outgoingList, 
+            byte state, KmerBytesWritable mergeChain) {
+        set(incomingList, outgoingList, state, mergeChain);
+    }
+
+    public void set(PositionListWritable incomingList, PositionListWritable outgoingList, 
+            byte state, KmerBytesWritable mergeChain) {
+        this.incomingList.set(incomingList);
+        this.outgoingList.set(outgoingList);
         this.state = state;
         this.mergeChain.set(mergeChain);
     }
-
-    public void set(byte adjMap, byte state, VKmerBytesWritable mergeChain) {
-        this.adjMap = adjMap;
-        this.state = state;
-        this.mergeChain.set(mergeChain);
+    
+    public PositionListWritable getIncomingList() {
+        return incomingList;
     }
 
-    public byte getAdjMap() {
-        return adjMap;
+    public void setIncomingList(PositionListWritable incomingList) {
+        this.incomingList = incomingList;
     }
 
-    public void setAdjMap(byte adjMap) {
-        this.adjMap = adjMap;
+    public PositionListWritable getOutgoingList() {
+        return outgoingList;
+    }
+
+    public void setOutgoingList(PositionListWritable outgoingList) {
+        this.outgoingList = outgoingList;
     }
 
     public byte getState() {
@@ -53,7 +63,7 @@
         return mergeChain.getKmerLength();
     }
 
-    public VKmerBytesWritable getMergeChain() {
+    public KmerBytesWritable getMergeChain() {
         return mergeChain;
     }
 
@@ -61,20 +71,18 @@
         this.mergeChain.set(mergeChain);
     }
 
-    public void setMergeChain(VKmerBytesWritable mergeChain) {
-        this.mergeChain.set(mergeChain);
-    }
-
     @Override
     public void readFields(DataInput in) throws IOException {
-        adjMap = in.readByte();
+        incomingList.readFields(in);
+        outgoingList.readFields(in);
         state = in.readByte();
         mergeChain.readFields(in);
     }
 
     @Override
     public void write(DataOutput out) throws IOException {
-        out.writeByte(adjMap);
+        incomingList.write(out);
+        outgoingList.write(out);
         out.writeByte(state);
         mergeChain.write(out);
     }
@@ -86,7 +94,14 @@
 
     @Override
     public String toString() {
-        return GeneCode.getSymbolFromBitMap(adjMap) + "\t" + getLengthOfMergeChain() + "\t" + mergeChain.toString();
+        return state + "\t" + getLengthOfMergeChain() + "\t" + mergeChain.toString();
+    }
+    
+    public int inDegree() {
+        return incomingList.getCountOfPosition();
     }
 
+    public int outDegree() {
+        return outgoingList.getCountOfPosition();
+    }
 }
diff --git a/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/log/DataLoadLogFormatter.java b/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/log/DataLoadLogFormatter.java
index ae950f4..95e070f 100644
--- a/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/log/DataLoadLogFormatter.java
+++ b/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/log/DataLoadLogFormatter.java
@@ -4,22 +4,19 @@
 import java.util.logging.Handler;
 import java.util.logging.LogRecord;
 
-import edu.uci.ics.genomix.type.KmerCountValue;
-import edu.uci.ics.genomix.type.VKmerBytesWritable;
+import edu.uci.ics.genomix.type.NodeWritable;
 
 public class DataLoadLogFormatter extends Formatter {
-    private VKmerBytesWritable key;
-    private KmerCountValue value;
+    private NodeWritable key;
 
-    public void set(VKmerBytesWritable key, KmerCountValue value) {
+    public void set(NodeWritable key) {
         this.key.set(key);
-        this.value = value;
     }
 
     public String format(LogRecord record) {
         StringBuilder builder = new StringBuilder(1000);
 
-        builder.append(key.toString() + "\t" + value.toString() + "\r\n");
+        builder.append(key.toString() + "\r\n");
 
         if (!formatMessage(record).equals(""))
             builder.append(formatMessage(record) + "\r\n");
diff --git a/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/log/LogAlgorithmLogFormatter.java b/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/log/LogAlgorithmLogFormatter.java
index 9eba176..dca2cb8 100644
--- a/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/log/LogAlgorithmLogFormatter.java
+++ b/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/log/LogAlgorithmLogFormatter.java
@@ -2,22 +2,21 @@
 
 import java.util.logging.*;
 
-import edu.uci.ics.genomix.pregelix.io.LogAlgorithmMessageWritable;
+import edu.uci.ics.genomix.pregelix.io.MessageWritable;
 import edu.uci.ics.genomix.pregelix.type.Message;
 import edu.uci.ics.genomix.pregelix.type.State;
-import edu.uci.ics.genomix.type.VKmerBytesWritable;
+import edu.uci.ics.genomix.type.KmerBytesWritable;
 
 public class LogAlgorithmLogFormatter extends Formatter {
     //
     // Create a DateFormat to format the logger timestamp.
     //
-    //private static final DateFormat df = new SimpleDateFormat("dd/MM/yyyy hh:mm:ss.SSS");
     private long step;
-    private VKmerBytesWritable sourceVertexId = new VKmerBytesWritable(1);
-    private VKmerBytesWritable destVertexId = new VKmerBytesWritable(1);
-    private LogAlgorithmMessageWritable msg = new LogAlgorithmMessageWritable();
+    private KmerBytesWritable sourceVertexId = new KmerBytesWritable(1);
+    private KmerBytesWritable destVertexId = new KmerBytesWritable(1);
+    private MessageWritable msg = new MessageWritable();
     private byte state;
-    private VKmerBytesWritable mergeChain = new VKmerBytesWritable(1);;
+    private KmerBytesWritable mergeChain = new KmerBytesWritable(1);;
     //private boolean testDelete = false;
     /**
      * 0: general operation
@@ -30,8 +29,8 @@
     public LogAlgorithmLogFormatter() {
     }
 
-    public void set(long step, VKmerBytesWritable sourceVertexId, VKmerBytesWritable destVertexId,
-            LogAlgorithmMessageWritable msg, byte state) {
+    public void set(long step, KmerBytesWritable sourceVertexId, KmerBytesWritable destVertexId,
+            MessageWritable msg, byte state) {
         this.step = step;
         this.sourceVertexId.set(sourceVertexId);
         this.destVertexId.set(destVertexId);
@@ -40,7 +39,7 @@
         this.operation = 0;
     }
 
-    public void setMergeChain(long step, VKmerBytesWritable sourceVertexId, VKmerBytesWritable mergeChain) {
+    public void setMergeChain(long step, KmerBytesWritable sourceVertexId, KmerBytesWritable mergeChain) {
         this.reset();
         this.step = step;
         this.sourceVertexId.set(sourceVertexId);
@@ -48,7 +47,7 @@
         this.operation = 2;
     }
 
-    public void setVotoToHalt(long step, VKmerBytesWritable sourceVertexId) {
+    public void setVotoToHalt(long step, KmerBytesWritable sourceVertexId) {
         this.reset();
         this.step = step;
         this.sourceVertexId.set(sourceVertexId);
@@ -56,11 +55,11 @@
     }
 
     public void reset() {
-        this.sourceVertexId = new VKmerBytesWritable(1);
-        this.destVertexId = new VKmerBytesWritable(1);
-        this.msg = new LogAlgorithmMessageWritable();
+        this.sourceVertexId = new KmerBytesWritable(1);
+        this.destVertexId = new KmerBytesWritable(1);
+        this.msg = new MessageWritable();
         this.state = 0;
-        this.mergeChain = new VKmerBytesWritable(1);
+        this.mergeChain = new KmerBytesWritable(1);
     }
 
     public String format(LogRecord record) {
diff --git a/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/log/NaiveAlgorithmLogFormatter.java b/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/log/NaiveAlgorithmLogFormatter.java
index 39b0bc1..4a5850a 100644
--- a/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/log/NaiveAlgorithmLogFormatter.java
+++ b/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/log/NaiveAlgorithmLogFormatter.java
@@ -2,7 +2,7 @@
 
 import java.util.logging.*;
 
-import edu.uci.ics.genomix.type.VKmerBytesWritable;
+import edu.uci.ics.genomix.type.KmerBytesWritable;
 
 public class NaiveAlgorithmLogFormatter extends Formatter {
     //
@@ -10,10 +10,10 @@
     //
     //private static final DateFormat df = new SimpleDateFormat("dd/MM/yyyy hh:mm:ss.SSS");
     private long step;
-    private VKmerBytesWritable sourceVertexId;
-    private VKmerBytesWritable destVertexId;
+    private KmerBytesWritable sourceVertexId;
+    private KmerBytesWritable destVertexId;
 
-    public void set(long step, VKmerBytesWritable sourceVertexId, VKmerBytesWritable destVertexId) {
+    public void set(long step, KmerBytesWritable sourceVertexId, KmerBytesWritable destVertexId) {
         this.step = step;
         this.sourceVertexId.set(sourceVertexId);
         this.destVertexId.set(destVertexId);
diff --git a/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/operator/LogAlgorithmForPathMergeVertex.java b/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/operator/LogAlgorithmForPathMergeVertex.java
index b033c28..6be0eee 100644
--- a/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/operator/LogAlgorithmForPathMergeVertex.java
+++ b/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/operator/LogAlgorithmForPathMergeVertex.java
@@ -9,21 +9,19 @@
 import edu.uci.ics.genomix.pregelix.client.Client;
 import edu.uci.ics.genomix.pregelix.format.LogAlgorithmForPathMergeInputFormat;
 import edu.uci.ics.genomix.pregelix.format.LogAlgorithmForPathMergeOutputFormat;
-import edu.uci.ics.genomix.pregelix.io.LogAlgorithmMessageWritable;
+import edu.uci.ics.genomix.pregelix.io.MessageWritable;
 import edu.uci.ics.genomix.pregelix.io.ValueStateWritable;
 import edu.uci.ics.genomix.pregelix.type.Message;
 import edu.uci.ics.genomix.pregelix.type.State;
 import edu.uci.ics.genomix.pregelix.util.VertexUtil;
-import edu.uci.ics.genomix.type.GeneCode;
 import edu.uci.ics.genomix.type.KmerBytesWritable;
-import edu.uci.ics.genomix.type.VKmerBytesWritable;
-import edu.uci.ics.genomix.type.VKmerBytesWritableFactory;
-
+import edu.uci.ics.genomix.type.KmerBytesWritableFactory;
+import edu.uci.ics.genomix.type.PositionWritable;
 /*
  * vertexId: BytesWritable
  * vertexValue: ValueStateWritable
  * edgeValue: NullWritable
- * message: LogAlgorithmMessageWritable
+ * message: MessageWritable
  * 
  * DNA:
  * A: 00
@@ -48,19 +46,20 @@
  * The details about message are in edu.uci.ics.pregelix.example.io.MessageWritable. 
  */
 public class LogAlgorithmForPathMergeVertex extends
-        Vertex<KmerBytesWritable, ValueStateWritable, NullWritable, LogAlgorithmMessageWritable> {
+        Vertex<PositionWritable, ValueStateWritable, NullWritable, MessageWritable> {
     public static final String KMER_SIZE = "LogAlgorithmForPathMergeVertex.kmerSize";
     public static final String ITERATIONS = "LogAlgorithmForPathMergeVertex.iteration";
     public static int kmerSize = -1;
     private int maxIteration = -1;
 
-    private LogAlgorithmMessageWritable incomingMsg = new LogAlgorithmMessageWritable();
-    private LogAlgorithmMessageWritable outgoingMsg = new LogAlgorithmMessageWritable();
+    private MessageWritable incomingMsg = new MessageWritable();
+    private MessageWritable outgoingMsg = new MessageWritable();
 
-    private VKmerBytesWritableFactory kmerFactory = new VKmerBytesWritableFactory(1);
-    private VKmerBytesWritable chainVertexId = new VKmerBytesWritable(1);
-    private VKmerBytesWritable lastKmer = new VKmerBytesWritable(1);
+    private KmerBytesWritableFactory kmerFactory = new KmerBytesWritableFactory(1);
+    private KmerBytesWritable lastKmer = new KmerBytesWritable(1);
 
+    private PositionWritable destVertexId = new PositionWritable();
+    private Iterator<PositionWritable> posIterator;
     /**
      * initiate kmerSize, maxIteration
      */
@@ -75,42 +74,35 @@
     /**
      * get destination vertex
      */
-    public VKmerBytesWritable getNextDestVertexId(KmerBytesWritable vertexId, byte geneCode) {
-        return kmerFactory.shiftKmerWithNextCode(vertexId, geneCode);
+    public PositionWritable getNextDestVertexId(ValueStateWritable value) {
+        posIterator = value.getOutgoingList().iterator();
+        return posIterator.next();
     }
 
-    public VKmerBytesWritable getPreDestVertexId(KmerBytesWritable vertexId, byte geneCode) {
-        return kmerFactory.shiftKmerWithPreCode(vertexId, geneCode);
-    }
-
-    public VKmerBytesWritable getNextDestVertexIdFromBitmap(KmerBytesWritable chainVertexId, byte adjMap) {
-        return getDestVertexIdFromChain(chainVertexId, adjMap);
-    }
-
-    public VKmerBytesWritable getDestVertexIdFromChain(KmerBytesWritable chainVertexId, byte adjMap) {
-        VKmerBytesWritable lastKmer = kmerFactory.getLastKmerFromChain(kmerSize, chainVertexId);
-        return getNextDestVertexId(lastKmer, GeneCode.getGeneCodeFromBitMap((byte) (adjMap & 0x0F)));
+    public PositionWritable getPreDestVertexId(ValueStateWritable value) {
+        posIterator = value.getIncomingList().iterator();
+        return posIterator.next();
     }
 
     /**
      * head send message to all next nodes
      */
-    public void sendMsgToAllNextNodes(KmerBytesWritable vertexId, byte adjMap) {
-        for (byte x = GeneCode.A; x <= GeneCode.T; x++) {
-            if ((adjMap & (1 << x)) != 0) {
-                sendMsg(getNextDestVertexId(vertexId, x), outgoingMsg);
-            }
+    public void sendMsgToAllNextNodes(ValueStateWritable value) {
+        posIterator = value.getOutgoingList().iterator();
+        while(posIterator.hasNext()){
+            destVertexId.set(posIterator.next());
+            sendMsg(destVertexId, outgoingMsg);
         }
     }
 
     /**
      * head send message to all previous nodes
      */
-    public void sendMsgToAllPreviousNodes(KmerBytesWritable vertexId, byte adjMap) {
-        for (byte x = GeneCode.A; x <= GeneCode.T; x++) {
-            if (((adjMap >> 4) & (1 << x)) != 0) {
-                sendMsg(getPreDestVertexId(vertexId, x), outgoingMsg);
-            }
+    public void sendMsgToAllPreviousNodes(ValueStateWritable value) {
+        posIterator = value.getIncomingList().iterator();
+        while(posIterator.hasNext()){
+            destVertexId.set(posIterator.next());
+            sendMsg(destVertexId, outgoingMsg);
         }
     }
 
@@ -118,14 +110,14 @@
      * start sending message
      */
     public void startSendMsg() {
-        if (VertexUtil.isHeadVertex(getVertexValue().getAdjMap())) {
+        if (VertexUtil.isHeadVertex(getVertexValue())) {
             outgoingMsg.setMessage(Message.START);
-            sendMsgToAllNextNodes(getVertexId(), getVertexValue().getAdjMap());
+            sendMsgToAllNextNodes(getVertexValue());
             voteToHalt();
         }
-        if (VertexUtil.isRearVertex(getVertexValue().getAdjMap())) {
+        if (VertexUtil.isRearVertex(getVertexValue())) {
             outgoingMsg.setMessage(Message.END);
-            sendMsgToAllPreviousNodes(getVertexId(), getVertexValue().getAdjMap());
+            sendMsgToAllPreviousNodes(getVertexValue());
             voteToHalt();
         }
     }
@@ -133,9 +125,9 @@
     /**
      * initiate head, rear and path node
      */
-    public void initState(Iterator<LogAlgorithmMessageWritable> msgIterator) {
+    public void initState(Iterator<MessageWritable> msgIterator) {
         while (msgIterator.hasNext()) {
-            if (!VertexUtil.isPathVertex(getVertexValue().getAdjMap())) {
+            if (!VertexUtil.isPathVertex(getVertexValue())) {
                 msgIterator.next();
                 voteToHalt();
             } else {
@@ -154,7 +146,7 @@
             getVertexValue().setMergeChain(null);
         } else if (incomingMsg.getMessage() == Message.END && getVertexValue().getState() != State.START_VERTEX) {
             getVertexValue().setState(State.END_VERTEX);
-            getVertexValue().setMergeChain(getVertexId());
+            getVertexValue().setMergeChain(getVertexValue().getMergeChain());
             voteToHalt();
         } else
             voteToHalt();
@@ -163,29 +155,29 @@
     /**
      * head send message to path
      */
-    public void sendOutMsg(KmerBytesWritable chainVertexId, byte adjMap) {
+    public void sendOutMsg() {
         if (getVertexValue().getState() == State.START_VERTEX) {
             outgoingMsg.setMessage(Message.START);
             outgoingMsg.setSourceVertexId(getVertexId());
-            sendMsg(getNextDestVertexIdFromBitmap(chainVertexId, adjMap), outgoingMsg);
+            sendMsg(getNextDestVertexId(getVertexValue()), outgoingMsg);
         } else if (getVertexValue().getState() != State.END_VERTEX) {
             outgoingMsg.setMessage(Message.NON);
             outgoingMsg.setSourceVertexId(getVertexId());
-            sendMsg(getNextDestVertexIdFromBitmap(chainVertexId, adjMap), outgoingMsg);
+            sendMsg(getNextDestVertexId(getVertexValue()), outgoingMsg);
         }
     }
 
     /**
      * head send message to path
      */
-    public void sendMsgToPathVertex(Iterator<LogAlgorithmMessageWritable> msgIterator) {
+    public void sendMsgToPathVertex(Iterator<MessageWritable> msgIterator) {
         if (getSuperstep() == 3) {
-            getVertexValue().setMergeChain(getVertexId());
-            sendOutMsg(getVertexId(), getVertexValue().getAdjMap());
+            getVertexValue().setMergeChain(getVertexValue().getMergeChain());
+            sendOutMsg();
         } else {
             if (msgIterator.hasNext()) {
                 incomingMsg = msgIterator.next();
-                if (mergeChainVertex(msgIterator)) {
+                if (mergeChainVertex()) {
                     if (incomingMsg.getMessage() == Message.END) {
                         if (getVertexValue().getState() == State.START_VERTEX) {
                             getVertexValue().setState(State.FINAL_VERTEX);
@@ -194,7 +186,7 @@
                         } else
                             getVertexValue().setState(State.END_VERTEX);
                     } else
-                        sendOutMsg(getVertexValue().getMergeChain(), getVertexValue().getAdjMap());
+                        sendOutMsg();
                 }
             }
         }
@@ -203,11 +195,11 @@
     /**
      * path response message to head
      */
-    public void responseMsgToHeadVertex(Iterator<LogAlgorithmMessageWritable> msgIterator) {
+    public void responseMsgToHeadVertex(Iterator<MessageWritable> msgIterator) {
         if (msgIterator.hasNext()) {
             incomingMsg = msgIterator.next();
             outgoingMsg.setChainVertexId(getVertexValue().getMergeChain());
-            outgoingMsg.setAdjMap(getVertexValue().getAdjMap());
+            outgoingMsg.setNeighberNode(getVertexValue().getOutgoingList());
             if (getVertexValue().getState() == State.END_VERTEX)
                 outgoingMsg.setMessage(Message.END);
             sendMsg(incomingMsg.getSourceVertexId(), outgoingMsg);
@@ -223,28 +215,23 @@
     /**
      * merge chainVertex and store in vertexVal.chainVertexId
      */
-    public boolean mergeChainVertex(Iterator<LogAlgorithmMessageWritable> msgIterator) {
+    public boolean mergeChainVertex() {
         //merge chain
         lastKmer.set(kmerFactory.getLastKmerFromChain(incomingMsg.getLengthOfChain() - kmerSize + 1,
                 incomingMsg.getChainVertexId()));
-        chainVertexId.set(kmerFactory.mergeTwoKmer(getVertexValue().getMergeChain(), lastKmer));
-        if (VertexUtil.isCycle(getVertexId(), chainVertexId, kmerSize)) {
-            getVertexValue().setMergeChain(null);
-            getVertexValue().setAdjMap(
-                    VertexUtil.reverseAdjMap(getVertexValue().getAdjMap(),
-                            chainVertexId.getGeneCodeAtPosition(kmerSize)));
+        KmerBytesWritable chainVertexId = kmerFactory.mergeTwoKmer(getVertexValue().getMergeChain(), lastKmer);
+        getVertexValue().setMergeChain(chainVertexId);
+        getVertexValue().setOutgoingList(incomingMsg.getNeighberNode());
+        if (VertexUtil.isCycle(kmerFactory.getFirstKmerFromChain(kmerSize, getVertexValue().getMergeChain()),
+                chainVertexId, kmerSize)) {
             getVertexValue().setState(State.CYCLE);
             return false;
-        } else
-            getVertexValue().setMergeChain(chainVertexId);
-
-        byte tmpVertexValue = VertexUtil.updateRightNeighber(getVertexValue().getAdjMap(), incomingMsg.getAdjMap());
-        getVertexValue().setAdjMap(tmpVertexValue);
+        } 
         return true;
     }
 
     @Override
-    public void compute(Iterator<LogAlgorithmMessageWritable> msgIterator) {
+    public void compute(Iterator<MessageWritable> msgIterator) {
         initVertex();
         if (getSuperstep() == 1)
             startSendMsg();
@@ -268,7 +255,7 @@
          */
         job.setVertexInputFormatClass(LogAlgorithmForPathMergeInputFormat.class);
         job.setVertexOutputFormatClass(LogAlgorithmForPathMergeOutputFormat.class);
-        job.setOutputKeyClass(KmerBytesWritable.class);
+        job.setOutputKeyClass(PositionWritable.class);
         job.setOutputValueClass(ValueStateWritable.class);
         job.setDynamicVertexValueSize(true);
         Client.run(args, job);
diff --git a/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/operator/NaiveAlgorithmForPathMergeVertex.java b/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/operator/NaiveAlgorithmForPathMergeVertex.java
index b637f84..af38072 100644
--- a/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/operator/NaiveAlgorithmForPathMergeVertex.java
+++ b/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/operator/NaiveAlgorithmForPathMergeVertex.java
@@ -3,17 +3,16 @@
 import java.util.Iterator;
 import org.apache.hadoop.io.NullWritable;
 
-import edu.uci.ics.genomix.type.GeneCode;
 import edu.uci.ics.genomix.type.KmerBytesWritable;
-import edu.uci.ics.genomix.type.VKmerBytesWritable;
-import edu.uci.ics.genomix.type.VKmerBytesWritableFactory;
+import edu.uci.ics.genomix.type.KmerBytesWritableFactory;
+import edu.uci.ics.genomix.type.PositionWritable;
 
 import edu.uci.ics.pregelix.api.graph.Vertex;
 import edu.uci.ics.pregelix.api.job.PregelixJob;
 import edu.uci.ics.genomix.pregelix.client.Client;
 import edu.uci.ics.genomix.pregelix.format.NaiveAlgorithmForPathMergeInputFormat;
 import edu.uci.ics.genomix.pregelix.format.NaiveAlgorithmForPathMergeOutputFormat;
-import edu.uci.ics.genomix.pregelix.io.NaiveAlgorithmMessageWritable;
+import edu.uci.ics.genomix.pregelix.io.MessageWritable;
 import edu.uci.ics.genomix.pregelix.io.ValueStateWritable;
 import edu.uci.ics.genomix.pregelix.type.Message;
 import edu.uci.ics.genomix.pregelix.type.State;
@@ -23,7 +22,7 @@
  * vertexId: BytesWritable
  * vertexValue: ByteWritable
  * edgeValue: NullWritable
- * message: NaiveAlgorithmMessageWritable
+ * message: MessageWritable
  * 
  * DNA:
  * A: 00
@@ -51,18 +50,21 @@
  * Naive Algorithm for path merge graph
  */
 public class NaiveAlgorithmForPathMergeVertex extends
-        Vertex<KmerBytesWritable, ValueStateWritable, NullWritable, NaiveAlgorithmMessageWritable> {
+        Vertex<PositionWritable, ValueStateWritable, NullWritable, MessageWritable> {
     public static final String KMER_SIZE = "NaiveAlgorithmForPathMergeVertex.kmerSize";
     public static final String ITERATIONS = "NaiveAlgorithmForPathMergeVertex.iteration";
     public static int kmerSize = -1;
     private int maxIteration = -1;
 
-    private NaiveAlgorithmMessageWritable incomingMsg = new NaiveAlgorithmMessageWritable();
-    private NaiveAlgorithmMessageWritable outgoingMsg = new NaiveAlgorithmMessageWritable();
-
-    private VKmerBytesWritableFactory kmerFactory = new VKmerBytesWritableFactory(1);
-    private VKmerBytesWritable destVertexId = new VKmerBytesWritable(1);
-
+    private MessageWritable incomingMsg = new MessageWritable();
+    private MessageWritable outgoingMsg = new MessageWritable();
+  
+    private KmerBytesWritableFactory kmerFactory = new KmerBytesWritableFactory(1);
+    private KmerBytesWritable lastKmer = new KmerBytesWritable(1);
+    
+    private PositionWritable destVertexId = new PositionWritable();
+    private Iterator<PositionWritable> posIterator;
+    
     /**
      * initiate kmerSize, maxIteration
      */
@@ -77,40 +79,35 @@
     /**
      * get destination vertex
      */
-    public VKmerBytesWritable getDestVertexId(KmerBytesWritable vertexId, byte geneCode) {
-        return kmerFactory.shiftKmerWithNextCode(vertexId, geneCode);
+    public PositionWritable getNextDestVertexId(ValueStateWritable value) {
+        posIterator = value.getOutgoingList().iterator();
+        return posIterator.next();
     }
 
-    public VKmerBytesWritable getPreDestVertexId(KmerBytesWritable vertexId, byte geneCode) {
-        return kmerFactory.shiftKmerWithPreCode(vertexId, geneCode);
-    }
-
-    public VKmerBytesWritable getDestVertexIdFromChain(VKmerBytesWritable chainVertexId, byte adjMap) {
-        VKmerBytesWritable lastKmer = kmerFactory.getLastKmerFromChain(kmerSize, chainVertexId);
-        return getDestVertexId(lastKmer, GeneCode.getGeneCodeFromBitMap((byte) (adjMap & 0x0F)));
+    public PositionWritable getPreDestVertexId(ValueStateWritable value) {
+        posIterator = value.getIncomingList().iterator();
+        return posIterator.next();
     }
 
     /**
      * head send message to all next nodes
      */
-    public void sendMsgToAllNextNodes(KmerBytesWritable vertexId, byte adjMap) {
-        for (byte x = GeneCode.A; x <= GeneCode.T; x++) {
-            if ((adjMap & (1 << x)) != 0) {
-                destVertexId.set(getDestVertexId(vertexId, x));
-                sendMsg(destVertexId, outgoingMsg);
-            }
+    public void sendMsgToAllNextNodes(ValueStateWritable value) {
+        posIterator = value.getOutgoingList().iterator();
+        while(posIterator.hasNext()){
+            destVertexId.set(posIterator.next());
+            sendMsg(destVertexId, outgoingMsg);
         }
     }
 
     /**
      * head send message to all previous nodes
      */
-    public void sendMsgToAllPreviousNodes(KmerBytesWritable vertexId, byte adjMap) {
-        for (byte x = GeneCode.A; x <= GeneCode.T; x++) {
-            if (((adjMap >> 4) & (1 << x)) != 0) {
-                destVertexId.set(getPreDestVertexId(vertexId, x));
-                sendMsg(destVertexId, outgoingMsg);
-            }
+    public void sendMsgToAllPreviousNodes(ValueStateWritable value) {
+        posIterator = value.getIncomingList().iterator();
+        while(posIterator.hasNext()){
+            destVertexId.set(posIterator.next());
+            sendMsg(destVertexId, outgoingMsg);
         }
     }
 
@@ -118,22 +115,22 @@
      * start sending message
      */
     public void startSendMsg() {
-        if (VertexUtil.isHeadVertex(getVertexValue().getAdjMap())) {
+        if (VertexUtil.isHeadVertex(getVertexValue())) {
             outgoingMsg.setMessage(Message.START);
-            sendMsgToAllNextNodes(getVertexId(), getVertexValue().getAdjMap());
+            sendMsgToAllNextNodes(getVertexValue());
         }
-        if (VertexUtil.isRearVertex(getVertexValue().getAdjMap())) {
+        if (VertexUtil.isRearVertex(getVertexValue())) {
             outgoingMsg.setMessage(Message.END);
-            sendMsgToAllPreviousNodes(getVertexId(), getVertexValue().getAdjMap());
+            sendMsgToAllPreviousNodes(getVertexValue());
         }
     }
 
     /**
      * initiate head, rear and path node
      */
-    public void initState(Iterator<NaiveAlgorithmMessageWritable> msgIterator) {
+    public void initState(Iterator<MessageWritable> msgIterator) {
         while (msgIterator.hasNext()) {
-            if (!VertexUtil.isPathVertex(getVertexValue().getAdjMap())) {
+            if (!VertexUtil.isPathVertex(getVertexValue())) {
                 msgIterator.next();
                 voteToHalt();
             } else {
@@ -155,33 +152,36 @@
         } else
             voteToHalt();
     }
+    
+    /**
+     * merge chainVertex and store in vertexVal.chainVertexId
+     */
+    public void mergeChainVertex() {
+        //merge chain
+        lastKmer.set(kmerFactory.getLastKmerFromChain(incomingMsg.getLengthOfChain() - kmerSize + 1,
+                incomingMsg.getChainVertexId()));
+        getVertexValue().setMergeChain(kmerFactory.mergeTwoKmer(getVertexValue().getMergeChain(), lastKmer));
+        getVertexValue().setOutgoingList(incomingMsg.getNeighberNode());
+    }
 
     /**
      * head node sends message to path node
      */
-    public void sendMsgToPathVertex(Iterator<NaiveAlgorithmMessageWritable> msgIterator) {
+    public void sendMsgToPathVertex(Iterator<MessageWritable> msgIterator) {
         if (getSuperstep() == 3) {
-            getVertexValue().setMergeChain(getVertexId());
             outgoingMsg.setSourceVertexId(getVertexId());
-            destVertexId.set(getDestVertexIdFromChain(getVertexValue().getMergeChain(), getVertexValue().getAdjMap()));
+            destVertexId.set(getNextDestVertexId(getVertexValue()));
             sendMsg(destVertexId, outgoingMsg);
         } else {
             while (msgIterator.hasNext()) {
                 incomingMsg = msgIterator.next();
                 if (incomingMsg.getMessage() != Message.STOP) {
-                    getVertexValue().setMergeChain(
-                            kmerFactory.mergeKmerWithNextCode(getVertexValue().getMergeChain(),
-                                    incomingMsg.getLastGeneCode()));
+                    mergeChainVertex();
                     outgoingMsg.setSourceVertexId(getVertexId());
-                    destVertexId
-                            .set(getDestVertexIdFromChain(getVertexValue().getMergeChain(), incomingMsg.getAdjMap()));
+                    destVertexId.set(getNextDestVertexId(getVertexValue()));
                     sendMsg(destVertexId, outgoingMsg);
                 } else {
-                    getVertexValue().setMergeChain(
-                            kmerFactory.mergeKmerWithNextCode(getVertexValue().getMergeChain(),
-                                    incomingMsg.getLastGeneCode()));
-                    byte adjMap = VertexUtil.updateRightNeighber(getVertexValue().getAdjMap(), incomingMsg.getAdjMap());
-                    getVertexValue().setAdjMap(adjMap);
+                    mergeChainVertex();
                     getVertexValue().setState(State.FINAL_VERTEX);
                     //String source = getVertexValue().getMergeChain().toString();
                     //System.out.println();
@@ -195,15 +195,16 @@
      */
     public void responseMsgToHeadVertex() {
         deleteVertex(getVertexId());
-        outgoingMsg.setAdjMap(getVertexValue().getAdjMap());
-        outgoingMsg.setLastGeneCode(getVertexId().getGeneCodeAtPosition(kmerSize - 1));
+        outgoingMsg.setNeighberNode(getVertexValue().getOutgoingList());
+        outgoingMsg.setChainVertexId(getVertexValue().getMergeChain());
         if (getVertexValue().getState() == State.END_VERTEX)
             outgoingMsg.setMessage(Message.STOP);
-        sendMsg(incomingMsg.getSourceVertexId(), outgoingMsg);
+        destVertexId.set(incomingMsg.getSourceVertexId());
+        sendMsg(destVertexId, outgoingMsg);
     }
 
     @Override
-    public void compute(Iterator<NaiveAlgorithmMessageWritable> msgIterator) {
+    public void compute(Iterator<MessageWritable> msgIterator) {
         initVertex();
         if (getSuperstep() == 1) {
             startSendMsg();
@@ -232,7 +233,7 @@
         job.setVertexInputFormatClass(NaiveAlgorithmForPathMergeInputFormat.class);
         job.setVertexOutputFormatClass(NaiveAlgorithmForPathMergeOutputFormat.class);
         job.setDynamicVertexValueSize(true);
-        job.setOutputKeyClass(KmerBytesWritable.class);
+        job.setOutputKeyClass(PositionWritable.class);
         job.setOutputValueClass(ValueStateWritable.class);
         Client.run(args, job);
     }
diff --git a/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/operator/P3ForPathMergeVertex.java b/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/operator/P3ForPathMergeVertex.java
index 44d47a0..6f4354a 100644
--- a/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/operator/P3ForPathMergeVertex.java
+++ b/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/operator/P3ForPathMergeVertex.java
@@ -3,17 +3,16 @@
 import java.util.Iterator;
 import org.apache.hadoop.io.NullWritable;
 
-import edu.uci.ics.genomix.type.GeneCode;
 import edu.uci.ics.genomix.type.KmerBytesWritable;
-import edu.uci.ics.genomix.type.VKmerBytesWritable;
-import edu.uci.ics.genomix.type.VKmerBytesWritableFactory;
+import edu.uci.ics.genomix.type.KmerBytesWritableFactory;
+import edu.uci.ics.genomix.type.PositionWritable;
 
 import edu.uci.ics.pregelix.api.graph.Vertex;
 import edu.uci.ics.pregelix.api.job.PregelixJob;
 import edu.uci.ics.genomix.pregelix.client.Client;
 import edu.uci.ics.genomix.pregelix.format.NaiveAlgorithmForPathMergeInputFormat;
 import edu.uci.ics.genomix.pregelix.format.NaiveAlgorithmForPathMergeOutputFormat;
-import edu.uci.ics.genomix.pregelix.io.NaiveAlgorithmMessageWritable;
+import edu.uci.ics.genomix.pregelix.io.MessageWritable;
 import edu.uci.ics.genomix.pregelix.io.ValueStateWritable;
 import edu.uci.ics.genomix.pregelix.type.Message;
 import edu.uci.ics.genomix.pregelix.type.State;
@@ -23,7 +22,7 @@
  * vertexId: BytesWritable
  * vertexValue: ByteWritable
  * edgeValue: NullWritable
- * message: NaiveAlgorithmMessageWritable
+ * message: MessageWritable
  * 
  * DNA:
  * A: 00
@@ -51,7 +50,7 @@
  * Naive Algorithm for path merge graph
  */
 public class P3ForPathMergeVertex extends
-        Vertex<KmerBytesWritable, ValueStateWritable, NullWritable, NaiveAlgorithmMessageWritable> {
+        Vertex<PositionWritable, ValueStateWritable, NullWritable, MessageWritable> {
     public static final String KMER_SIZE = "P3ForPathMergeVertex.kmerSize";
     public static final String ITERATIONS = "P3ForPathMergeVertex.iteration";
     public static final String PSEUDORATE = "P3ForPathMergeVertex.pseudoRate";
@@ -61,13 +60,14 @@
     public static float pseudoRate = -1;
     public static int maxRound = -1;
 
-    private NaiveAlgorithmMessageWritable incomingMsg = new NaiveAlgorithmMessageWritable();
-    private NaiveAlgorithmMessageWritable outgoingMsg = new NaiveAlgorithmMessageWritable();
+    private MessageWritable incomingMsg = new MessageWritable();
+    private MessageWritable outgoingMsg = new MessageWritable();
 
-    private VKmerBytesWritableFactory kmerFactory = new VKmerBytesWritableFactory(1);
-    private VKmerBytesWritable lastKmer = new VKmerBytesWritable(1);
-    private VKmerBytesWritable destVertexId = new VKmerBytesWritable(1);
+    private KmerBytesWritableFactory kmerFactory = new KmerBytesWritableFactory(1);
+    private KmerBytesWritable lastKmer = new KmerBytesWritable(1);
 
+    private PositionWritable destVertexId = new PositionWritable();
+    private Iterator<PositionWritable> posIterator;
     /**
      * initiate kmerSize, maxIteration
      */
@@ -86,40 +86,35 @@
     /**
      * get destination vertex
      */
-    public VKmerBytesWritable getDestVertexId(KmerBytesWritable vertexId, byte geneCode) {
-        return kmerFactory.shiftKmerWithNextCode(vertexId, geneCode);
+    public PositionWritable getNextDestVertexId(ValueStateWritable value) {
+        posIterator = value.getOutgoingList().iterator();
+        return posIterator.next();
     }
 
-    public VKmerBytesWritable getPreDestVertexId(KmerBytesWritable vertexId, byte geneCode) {
-        return kmerFactory.shiftKmerWithPreCode(vertexId, geneCode);
-    }
-
-    public VKmerBytesWritable getDestVertexIdFromChain(VKmerBytesWritable chainVertexId, byte adjMap) {
-        VKmerBytesWritable lastKmer = kmerFactory.getLastKmerFromChain(kmerSize, chainVertexId);
-        return getDestVertexId(lastKmer, GeneCode.getGeneCodeFromBitMap((byte) (adjMap & 0x0F)));
+    public PositionWritable getPreDestVertexId(ValueStateWritable value) {
+        posIterator = value.getIncomingList().iterator();
+        return posIterator.next();
     }
 
     /**
      * head send message to all next nodes
      */
-    public void sendMsgToAllNextNodes(KmerBytesWritable vertexId, byte adjMap) {
-        for (byte x = GeneCode.A; x <= GeneCode.T; x++) {
-            if ((adjMap & (1 << x)) != 0) {
-                destVertexId.set(getDestVertexId(vertexId, x));
-                sendMsg(destVertexId, outgoingMsg);
-            }
+    public void sendMsgToAllNextNodes(ValueStateWritable value) {
+        posIterator = value.getOutgoingList().iterator();
+        while(posIterator.hasNext()){
+            destVertexId.set(posIterator.next());
+            sendMsg(destVertexId, outgoingMsg);
         }
     }
 
     /**
      * head send message to all previous nodes
      */
-    public void sendMsgToAllPreviousNodes(KmerBytesWritable vertexId, byte adjMap) {
-        for (byte x = GeneCode.A; x <= GeneCode.T; x++) {
-            if (((adjMap >> 4) & (1 << x)) != 0) {
-                destVertexId.set(getPreDestVertexId(vertexId, x));
-                sendMsg(destVertexId, outgoingMsg);
-            }
+    public void sendMsgToAllPreviousNodes(ValueStateWritable value) {
+        posIterator = value.getIncomingList().iterator();
+        while(posIterator.hasNext()){
+            destVertexId.set(posIterator.next());
+            sendMsg(destVertexId, outgoingMsg);
         }
     }
 
@@ -127,25 +122,23 @@
      * start sending message
      */
     public void startSendMsg() {
-        if (VertexUtil.isHeadVertex(getVertexValue().getAdjMap())) {
+        if (VertexUtil.isHeadVertex(getVertexValue())) {
             outgoingMsg.setMessage(Message.START);
-            sendMsgToAllNextNodes(getVertexId(), getVertexValue().getAdjMap());
-            voteToHalt();
+            sendMsgToAllNextNodes(getVertexValue());
         }
-        if (VertexUtil.isRearVertex(getVertexValue().getAdjMap())) {
+        if (VertexUtil.isRearVertex(getVertexValue())) {
             outgoingMsg.setMessage(Message.END);
-            sendMsgToAllPreviousNodes(getVertexId(), getVertexValue().getAdjMap());
-            voteToHalt();
+            sendMsgToAllPreviousNodes(getVertexValue());
         }
     }
-
+    
     /**
      * initiate head, rear and path node
      */
-    public void initState(Iterator<NaiveAlgorithmMessageWritable> msgIterator) {
+    public void initState(Iterator<MessageWritable> msgIterator) {
         if (msgIterator.hasNext()) {
             do {
-                if (!VertexUtil.isPathVertex(getVertexValue().getAdjMap())) {
+                if (!VertexUtil.isPathVertex(getVertexValue())) {
                     msgIterator.next();
                     voteToHalt();
                 } else {
@@ -167,7 +160,20 @@
                 voteToHalt();*/
         }
     }
-
+    
+    /**
+     * set vertex state
+     */
+    public void setState() {
+        if (incomingMsg.getMessage() == Message.START) {
+            getVertexValue().setState(State.START_VERTEX);
+        } else if (incomingMsg.getMessage() == Message.END && getVertexValue().getState() != State.START_VERTEX) {
+            getVertexValue().setState(State.END_VERTEX);
+            voteToHalt();
+        } else
+            voteToHalt();
+    }
+   
     /**
      * mark the pseudoHead
      */
@@ -175,8 +181,7 @@
         getVertexValue().setState(State.PSEUDOHEAD);
         outgoingMsg.setMessage(Message.FROMPSEUDOHEAD);
         destVertexId
-                .set(getPreDestVertexId(getVertexId(), 
-                        GeneCode.getGeneCodeFromBitMap((byte) ((getVertexValue().getAdjMap() >> 4) & 0x0F))));
+                .set(getPreDestVertexId(getVertexValue()));
         sendMsg(destVertexId, outgoingMsg);
     }
 
@@ -194,45 +199,26 @@
             getVertexValue().setState(State.START_HALT);
         }
     }
-
-    /**
-     * set vertex state
-     */
-    public void setState() {
-        if (incomingMsg.getMessage() == Message.START) {
-            getVertexValue().setState(State.START_VERTEX);
-        } else if (incomingMsg.getMessage() == Message.END && getVertexValue().getState() != State.START_VERTEX) {
-            getVertexValue().setState(State.END_VERTEX);
-            voteToHalt();
-        } else
-            voteToHalt();
-    }
-    
+ 
     /**
      * merge chain vertex
      */
     public void mergeChainVertex(){
-        if(incomingMsg.isGeneCode() == true){
-            getVertexValue().setMergeChain(
-                    kmerFactory.mergeKmerWithNextCode(getVertexValue().getMergeChain(),
-                            incomingMsg.getLastGeneCode()));
-        }
-        else{
-            lastKmer.set(kmerFactory.getLastKmerFromChain(incomingMsg.getLengthOfChain() - kmerSize + 1,
-                    incomingMsg.getChainVertexId()));
-            getVertexValue().setMergeChain(
-                    kmerFactory.mergeTwoKmer(getVertexValue().getMergeChain(), 
-                            lastKmer));
-        }
+        lastKmer.set(kmerFactory.getLastKmerFromChain(incomingMsg.getLengthOfChain() - kmerSize + 1,
+                incomingMsg.getChainVertexId()));
+        getVertexValue().setMergeChain(
+                kmerFactory.mergeTwoKmer(getVertexValue().getMergeChain(), 
+                        lastKmer));
+        getVertexValue().setOutgoingList(incomingMsg.getNeighberNode());
     }
     
     /**
      * head node sends message to path node
      */
-    public void sendMsgToPathVertexMergePhase(Iterator<NaiveAlgorithmMessageWritable> msgIterator) {
+    public void sendMsgToPathVertexMergePhase(Iterator<MessageWritable> msgIterator) {
         if (getSuperstep() == 3 + 2 * maxRound + 2) {
             outgoingMsg.setSourceVertexId(getVertexId());
-            destVertexId.set(getDestVertexIdFromChain(getVertexValue().getMergeChain(), getVertexValue().getAdjMap()));
+            destVertexId.set(getNextDestVertexId(getVertexValue()));
             sendMsg(destVertexId, outgoingMsg);
         } else {
             while (msgIterator.hasNext()) {
@@ -241,12 +227,10 @@
                     mergeChainVertex();
                     outgoingMsg.setSourceVertexId(getVertexId());
                     destVertexId
-                            .set(getDestVertexIdFromChain(getVertexValue().getMergeChain(), incomingMsg.getAdjMap()));
+                            .set(getNextDestVertexId(getVertexValue()));
                     sendMsg(destVertexId, outgoingMsg);
                 } else {
                     mergeChainVertex();
-                    byte adjMap = VertexUtil.updateRightNeighber(getVertexValue().getAdjMap(), incomingMsg.getAdjMap());
-                    getVertexValue().setAdjMap(adjMap);
                     getVertexValue().setState(State.FINAL_VERTEX);
                     //String source = getVertexValue().getMergeChain().toString();
                     //System.out.println();
@@ -260,11 +244,8 @@
      */
     public void responseMsgToHeadVertexMergePhase() {
         deleteVertex(getVertexId());
-        outgoingMsg.setAdjMap(getVertexValue().getAdjMap());
-        if(getVertexValue().getLengthOfMergeChain() == 0)
-            outgoingMsg.setLastGeneCode(getVertexId().getGeneCodeAtPosition(kmerSize - 1));
-        else
-            outgoingMsg.setChainVertexId(getVertexValue().getMergeChain());
+        outgoingMsg.setNeighberNode(getVertexValue().getOutgoingList());
+        outgoingMsg.setChainVertexId(getVertexValue().getMergeChain());
         if (getVertexValue().getState() == State.END_VERTEX)
             outgoingMsg.setMessage(Message.STOP);
         sendMsg(incomingMsg.getSourceVertexId(), outgoingMsg);
@@ -273,12 +254,11 @@
     /**
      * head node sends message to path node in partition phase
      */
-    public void sendMsgToPathVertexPartitionPhase(Iterator<NaiveAlgorithmMessageWritable> msgIterator) {
+    public void sendMsgToPathVertexPartitionPhase(Iterator<MessageWritable> msgIterator) {
         if (getSuperstep() == 4) {
-            getVertexValue().setMergeChain(getVertexId());
             if(getVertexValue().getState() != State.START_HALT){
                 outgoingMsg.setSourceVertexId(getVertexId());
-                destVertexId.set(getDestVertexIdFromChain(getVertexValue().getMergeChain(), getVertexValue().getAdjMap()));
+                destVertexId.set(getNextDestVertexId(getVertexValue()));
                 sendMsg(destVertexId, outgoingMsg);
                 voteToHalt();
             }
@@ -288,13 +268,10 @@
                 //if from pseudoHead, voteToHalt(), otherwise ...
                 if (incomingMsg.getMessage() != Message.FROMPSEUDOHEAD){
                     mergeChainVertex();
-                    byte adjMap = VertexUtil.updateRightNeighber(getVertexValue().getAdjMap(), incomingMsg.getAdjMap());
-                    getVertexValue().setAdjMap(adjMap);
                     if (incomingMsg.getMessage() != Message.STOP 
                             && incomingMsg.getMessage() != Message.FROMPSEUDOREAR) {
                         outgoingMsg.setSourceVertexId(getVertexId());
-                        destVertexId.set(getDestVertexIdFromChain(getVertexValue().getMergeChain(),
-                                incomingMsg.getAdjMap()));
+                        destVertexId.set(getNextDestVertexId(getVertexValue()));
                         sendMsg(destVertexId, outgoingMsg);
                         voteToHalt();
                     } else {
@@ -321,11 +298,8 @@
             outgoingMsg.setMessage(Message.FROMPSEUDOHEAD);
         else {
             deleteVertex(getVertexId());
-            outgoingMsg.setAdjMap(getVertexValue().getAdjMap());
-            if(getVertexValue().getLengthOfMergeChain() == 0)
-                outgoingMsg.setLastGeneCode(getVertexId().getGeneCodeAtPosition(kmerSize - 1));
-            else
-                outgoingMsg.setChainVertexId(getVertexValue().getMergeChain());
+            outgoingMsg.setNeighberNode(incomingMsg.getNeighberNode());
+            outgoingMsg.setChainVertexId(getVertexValue().getMergeChain());
             if (getVertexValue().getState() == State.PSEUDOREAR)
                 outgoingMsg.setMessage(Message.FROMPSEUDOREAR);
             else if (getVertexValue().getState() == State.END_VERTEX)
@@ -338,12 +312,11 @@
     /**
      * final process the result of partition phase
      */
-    public void finalProcessPartitionPhase(Iterator<NaiveAlgorithmMessageWritable> msgIterator){
+    public void finalProcessPartitionPhase(Iterator<MessageWritable> msgIterator){
         while (msgIterator.hasNext()) {
             incomingMsg = msgIterator.next();
             mergeChainVertex();
-            byte adjMap = VertexUtil.updateRightNeighber(getVertexValue().getAdjMap(), incomingMsg.getAdjMap());
-            getVertexValue().setAdjMap(adjMap);
+            getVertexValue().setOutgoingList(incomingMsg.getNeighberNode());
             //check head or pseudoHead
             if (getVertexValue().getState() == State.START_VERTEX
                     && incomingMsg.getMessage() == Message.STOP) {
@@ -367,7 +340,7 @@
     }
 
     @Override
-    public void compute(Iterator<NaiveAlgorithmMessageWritable> msgIterator) {
+    public void compute(Iterator<MessageWritable> msgIterator) {
         initVertex();
         if (getSuperstep() == 1)
             startSendMsg();
@@ -411,7 +384,7 @@
         job.setVertexInputFormatClass(NaiveAlgorithmForPathMergeInputFormat.class);
         job.setVertexOutputFormatClass(NaiveAlgorithmForPathMergeOutputFormat.class);
         job.setDynamicVertexValueSize(true);
-        job.setOutputKeyClass(KmerBytesWritable.class);
+        job.setOutputKeyClass(PositionWritable.class);
         job.setOutputValueClass(ValueStateWritable.class);
         Client.run(args, job);
     }
diff --git a/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/sequencefile/CombineSequenceFile.java b/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/sequencefile/CombineSequenceFile.java
deleted file mode 100644
index 7a50537..0000000
--- a/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/sequencefile/CombineSequenceFile.java
+++ /dev/null
@@ -1,56 +0,0 @@
-package edu.uci.ics.genomix.pregelix.sequencefile;
-
-import java.io.File;
-
-import org.apache.hadoop.conf.Configuration;
-import org.apache.hadoop.fs.FileSystem;
-import org.apache.hadoop.fs.Path;
-import org.apache.hadoop.io.SequenceFile;
-import org.apache.hadoop.io.SequenceFile.CompressionType;
-
-import edu.uci.ics.genomix.type.KmerBytesWritable;
-import edu.uci.ics.genomix.type.KmerCountValue;
-
-public class CombineSequenceFile {
-
-    /**
-     * @param args
-     * @throws Exception
-     */
-    public static void main(String[] args) throws Exception {
-        // TODO Auto-generated method stub
-        int kmerSize = 5;
-        Configuration conf = new Configuration();
-        FileSystem fileSys = FileSystem.get(conf);
-
-        Path p = new Path("graphbuildresult/CyclePath2_result");
-        //Path p2 = new Path("data/result");
-        Path outFile = new Path("here");
-        SequenceFile.Reader reader;
-        SequenceFile.Writer writer = SequenceFile.createWriter(fileSys, conf, outFile, KmerBytesWritable.class,
-                KmerCountValue.class, CompressionType.NONE);
-        KmerBytesWritable key = new KmerBytesWritable(kmerSize);
-        KmerCountValue value = new KmerCountValue();
-
-        File dir = new File("graphbuildresult/CyclePath2_result");
-        for (File child : dir.listFiles()) {
-            String name = child.getAbsolutePath();
-            Path inFile = new Path(p, name);
-            reader = new SequenceFile.Reader(fileSys, inFile, conf);
-            while (reader.next(key, value)) {
-                System.out.println(key.toString() + "\t" + value.toString());
-                writer.append(key, value);
-            }
-            reader.close();
-        }
-        writer.close();
-        System.out.println();
-
-        reader = new SequenceFile.Reader(fileSys, outFile, conf);
-        while (reader.next(key, value)) {
-            System.err.println(key.toString() + "\t" + value.toString());
-        }
-        reader.close();
-    }
-
-}
diff --git a/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/sequencefile/GenerateSmallFile.java b/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/sequencefile/GenerateSmallFile.java
index bb288ff..6b9eb4e 100644
--- a/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/sequencefile/GenerateSmallFile.java
+++ b/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/sequencefile/GenerateSmallFile.java
@@ -12,11 +12,11 @@
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.fs.FileSystem;
 import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.io.NullWritable;
 import org.apache.hadoop.io.SequenceFile;
 import org.apache.hadoop.io.SequenceFile.CompressionType;
 
 import edu.uci.ics.genomix.type.KmerBytesWritable;
-import edu.uci.ics.genomix.type.KmerCountValue;
 
 public class GenerateSmallFile {
 
@@ -27,15 +27,14 @@
 
         SequenceFile.Reader reader = new SequenceFile.Reader(fileSys, inFile, conf);
         SequenceFile.Writer writer = SequenceFile.createWriter(fileSys, conf, outFile, KmerBytesWritable.class,
-                KmerCountValue.class, CompressionType.NONE);
+                NullWritable.class, CompressionType.NONE);
         KmerBytesWritable outKey = new KmerBytesWritable(55);
-        KmerCountValue outValue = new KmerCountValue();
         int i = 0;
 
         for (i = 0; i < numOfLines; i++) {
             // System.out.println(i);
-            reader.next(outKey, outValue);
-            writer.append(outKey, outValue);
+            reader.next(outKey, null);
+            writer.append(outKey, null);
         }
         writer.close();
         reader.close();
@@ -47,18 +46,6 @@
         writeTextFile(outFile, lines);
     }
 
-    public static void main(String[] args) throws IOException {
-        Path dir = new Path("data/split.aa");
-        Path outDir = new Path("data/input");
-        FileUtils.cleanDirectory(new File("data/input"));
-        Path inFile = new Path(dir, "part-0");
-        Path outFile = new Path(outDir, "part-0-out-1000");
-        generateNumOfLinesFromGraphBuildResuiltBigFile(inFile, outFile, 1000);
-      /*  String inFile = "data/shortjump_1.head8M.fastq";
-        String outFile = "data/testGeneFile";
-        generateNumOfLinesFromGraphBuildResuiltBigFile(inFile, outFile, 100000);*/
-    }
-
     public static String readTextFile(String fileName, int numOfLines) {
         String returnValue = "";
         FileReader file;
@@ -93,6 +80,17 @@
         } catch (IOException e) {
             e.printStackTrace();
         }
-
+    }
+    
+    public static void main(String[] args) throws IOException {
+        Path dir = new Path("data/split.aa");
+        Path outDir = new Path("data/input");
+        FileUtils.cleanDirectory(new File("data/input"));
+        Path inFile = new Path(dir, "part-0");
+        Path outFile = new Path(outDir, "part-0-out-1000");
+        generateNumOfLinesFromGraphBuildResuiltBigFile(inFile, outFile, 1000);
+      /*  String inFile = "data/shortjump_1.head8M.fastq";
+        String outFile = "data/testGeneFile";
+        generateNumOfLinesFromGraphBuildResuiltBigFile(inFile, outFile, 100000);*/
     }
 }
diff --git a/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/sequencefile/GenerateTextFile.java b/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/sequencefile/GenerateTextFile.java
index 517b9c3..45609c6 100644
--- a/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/sequencefile/GenerateTextFile.java
+++ b/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/sequencefile/GenerateTextFile.java
@@ -15,7 +15,6 @@
 import edu.uci.ics.genomix.pregelix.io.ValueStateWritable;
 import edu.uci.ics.genomix.pregelix.type.State;
 import edu.uci.ics.genomix.type.KmerBytesWritable;
-import edu.uci.ics.genomix.type.KmerCountValue;
 
 public class GenerateTextFile {
 
@@ -99,10 +98,9 @@
         Path path = new Path("data/input/part-0-out-3000000");
         SequenceFile.Reader reader = new SequenceFile.Reader(fileSys, path, conf);
         KmerBytesWritable key = new KmerBytesWritable(55);
-        KmerCountValue value = new KmerCountValue();
 
-        while (reader.next(key, value)) {
-            if (key == null || value == null) {
+        while (reader.next(key, null)) {
+            if (key == null) {
                 break;
             }
             bw.write(key.toString());
diff --git a/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/type/CheckMessage.java b/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/type/CheckMessage.java
index 61d2256..6e6a97a 100644
--- a/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/type/CheckMessage.java
+++ b/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/type/CheckMessage.java
@@ -4,7 +4,7 @@
 
     public static final byte SOURCE = 1 << 0;
     public static final byte CHAIN = 1 << 1;
-    public static final byte ADJMAP = 1 << 2;
+    public static final byte NEIGHBER = 1 << 2;
     public static final byte MESSAGE = 1 << 3;
     public static final byte STATE = 1 << 4;
     public static final byte LASTGENECODE = 1 << 5;
@@ -20,8 +20,8 @@
                 case CHAIN:
                     r = "CHAIN";
                     break;
-                case ADJMAP:
-                    r = "ADJMAP";
+                case NEIGHBER:
+                    r = "NEIGHBER";
                     break;
                 case MESSAGE:
                     r = "MESSAGE";
diff --git a/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/util/VertexUtil.java b/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/util/VertexUtil.java
index 50ff400..f2a61be 100644
--- a/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/util/VertexUtil.java
+++ b/genomix/genomix-pregelix/src/main/java/edu/uci/ics/genomix/pregelix/util/VertexUtil.java
@@ -1,19 +1,16 @@
 package edu.uci.ics.genomix.pregelix.util;
 
-import edu.uci.ics.genomix.type.GeneCode;
+import edu.uci.ics.genomix.pregelix.io.ValueStateWritable;
 import edu.uci.ics.genomix.type.KmerBytesWritable;
-import edu.uci.ics.genomix.type.VKmerBytesWritable;
 
 public class VertexUtil {
-    public static VKmerBytesWritable subKmer = new VKmerBytesWritable(0);
-
     /**
      * Single Vertex: in-degree = out-degree = 1
      * 
      * @param vertexValue
      */
-    public static boolean isPathVertex(byte value) {
-        if (GeneCode.inDegree(value) == 1 && GeneCode.outDegree(value) == 1)
+    public static boolean isPathVertex(ValueStateWritable value) {
+        if (value.inDegree() == 1 && value.outDegree() == 1)
             return true;
         return false;
     }
@@ -23,8 +20,8 @@
      * 
      * @param vertexValue
      */
-    public static boolean isHeadVertex(byte value) {
-        if (GeneCode.outDegree(value) > 0 && !isPathVertex(value))
+    public static boolean isHeadVertex(ValueStateWritable value) {
+        if (value.outDegree() > 0 && !isPathVertex(value))
             return true;
         return false;
     }
@@ -34,35 +31,18 @@
      * 
      * @param vertexValue
      */
-    public static boolean isRearVertex(byte value) {
-        if (GeneCode.inDegree(value) > 0 && !isPathVertex(value))
+    public static boolean isRearVertex(ValueStateWritable value) {
+        if (value.inDegree() > 0 && !isPathVertex(value))
             return true;
         return false;
     }
 
     /**
-     * update right neighber based on next vertexId
-     */
-    public static byte updateRightNeighberByVertexId(byte oldVertexValue, KmerBytesWritable neighberVertex, int k) {
-        byte geneCode = neighberVertex.getGeneCodeAtPosition(k - 1);
-
-        byte newBit = GeneCode.getBitMapFromGeneCode(geneCode); //getAdjBit
-        return (byte) ((byte) (oldVertexValue & 0xF0) | (byte) (newBit & 0x0F));
-    }
-
-    /**
-     * update right neighber
-     */
-    public static byte updateRightNeighber(byte oldVertexValue, byte newVertexValue) {
-        return (byte) ((byte) (oldVertexValue & 0xF0) | (byte) (newVertexValue & 0x0F));
-    }
-
-    /**
      * check if mergeChain is cycle
      */
-    public static boolean isCycle(KmerBytesWritable vertexId, VKmerBytesWritable mergeChain, int kmerSize) {
+    public static boolean isCycle(KmerBytesWritable kmer, KmerBytesWritable mergeChain, int kmerSize) {
         String chain = mergeChain.toString().substring(1);
-        if (chain.contains(vertexId.toString()))
+        if (chain.contains(kmer.toString()))
             return true;
         return false;
 
@@ -75,11 +55,4 @@
         }
         return false;*/
     }
-
-    /**
-     * reverse neighber
-     */
-    public static byte reverseAdjMap(byte oldAdjMap, byte geneCode) {
-        return (byte) ((oldAdjMap & 0xF0) | (GeneCode.getBitMapFromGeneCode(geneCode) & 0x0F));
-    }
 }
diff --git a/genomix/genomix-pregelix/src/test/java/edu/uci/ics/genomix/pregelix/JobGen/JobGenerator.java b/genomix/genomix-pregelix/src/test/java/edu/uci/ics/genomix/pregelix/JobGen/JobGenerator.java
index 809ea34..f1fcdac 100644
--- a/genomix/genomix-pregelix/src/test/java/edu/uci/ics/genomix/pregelix/JobGen/JobGenerator.java
+++ b/genomix/genomix-pregelix/src/test/java/edu/uci/ics/genomix/pregelix/JobGen/JobGenerator.java
@@ -4,15 +4,15 @@
 import java.io.FileOutputStream;
 import java.io.IOException;
 
+import edu.uci.ics.genomix.pregelix.format.LogAlgorithmForPathMergeInputFormat;
 import edu.uci.ics.genomix.pregelix.format.LogAlgorithmForPathMergeOutputFormat;
 import edu.uci.ics.genomix.pregelix.format.NaiveAlgorithmForPathMergeInputFormat;
 import edu.uci.ics.genomix.pregelix.format.NaiveAlgorithmForPathMergeOutputFormat;
-import edu.uci.ics.genomix.pregelix.format.LogAlgorithmForPathMergeInputFormat;
 import edu.uci.ics.genomix.pregelix.io.ValueStateWritable;
-import edu.uci.ics.genomix.pregelix.operator.NaiveAlgorithmForPathMergeVertex;
 import edu.uci.ics.genomix.pregelix.operator.LogAlgorithmForPathMergeVertex;
+import edu.uci.ics.genomix.pregelix.operator.NaiveAlgorithmForPathMergeVertex;
 import edu.uci.ics.genomix.pregelix.operator.P3ForPathMergeVertex;
-import edu.uci.ics.genomix.type.KmerBytesWritable;
+import edu.uci.ics.genomix.type.PositionWritable;
 import edu.uci.ics.pregelix.api.job.PregelixJob;
 
 public class JobGenerator {
@@ -25,7 +25,7 @@
         job.setVertexInputFormatClass(NaiveAlgorithmForPathMergeInputFormat.class);
         job.setVertexOutputFormatClass(NaiveAlgorithmForPathMergeOutputFormat.class);
         job.setDynamicVertexValueSize(true);
-        job.setOutputKeyClass(KmerBytesWritable.class);
+        job.setOutputKeyClass(PositionWritable.class);
         job.setOutputValueClass(ValueStateWritable.class);
         job.getConfiguration().setInt(NaiveAlgorithmForPathMergeVertex.KMER_SIZE, 5);
         job.getConfiguration().writeXml(new FileOutputStream(new File(outputPath)));
@@ -42,7 +42,7 @@
         job.setVertexInputFormatClass(LogAlgorithmForPathMergeInputFormat.class);
         job.setVertexOutputFormatClass(LogAlgorithmForPathMergeOutputFormat.class);
         job.setDynamicVertexValueSize(true);
-        job.setOutputKeyClass(KmerBytesWritable.class);
+        job.setOutputKeyClass(PositionWritable.class);
         job.setOutputValueClass(ValueStateWritable.class);
         job.getConfiguration().setInt(LogAlgorithmForPathMergeVertex.KMER_SIZE, 5);
         job.getConfiguration().writeXml(new FileOutputStream(new File(outputPath)));
@@ -58,7 +58,7 @@
         job.setVertexInputFormatClass(NaiveAlgorithmForPathMergeInputFormat.class);
         job.setVertexOutputFormatClass(NaiveAlgorithmForPathMergeOutputFormat.class);
         job.setDynamicVertexValueSize(true);
-        job.setOutputKeyClass(KmerBytesWritable.class);
+        job.setOutputKeyClass(PositionWritable.class);
         job.setOutputValueClass(ValueStateWritable.class);
         job.getConfiguration().setInt(P3ForPathMergeVertex.KMER_SIZE, 5);
         job.getConfiguration().setFloat(P3ForPathMergeVertex.PSEUDORATE, 0.4f);
@@ -72,8 +72,8 @@
     }
 
     public static void main(String[] args) throws IOException {
-        //genNaiveAlgorithmForMergeGraph();
-        //genLogAlgorithmForMergeGraph();
+        genNaiveAlgorithmForMergeGraph();
+        genLogAlgorithmForMergeGraph();
         genP3ForMergeGraph();
     }
 
diff --git a/genomix/genomix-pregelix/src/test/java/edu/uci/ics/genomix/pregelix/pathmerge/GraphBuildTest.java b/genomix/genomix-pregelix/src/test/java/edu/uci/ics/genomix/pregelix/pathmerge/GraphBuildTest.java
deleted file mode 100644
index 66ee26d..0000000
--- a/genomix/genomix-pregelix/src/test/java/edu/uci/ics/genomix/pregelix/pathmerge/GraphBuildTest.java
+++ /dev/null
@@ -1,176 +0,0 @@
-package edu.uci.ics.genomix.pregelix.pathmerge;
-
-import java.io.BufferedWriter;
-import java.io.DataOutputStream;
-import java.io.File;
-import java.io.FileOutputStream;
-import java.io.FileWriter;
-import java.io.IOException;
-
-import junit.framework.Assert;
-
-import org.apache.commons.io.FileUtils;
-import org.apache.hadoop.conf.Configuration;
-import org.apache.hadoop.fs.FileSystem;
-import org.apache.hadoop.fs.FileUtil;
-import org.apache.hadoop.fs.Path;
-import org.apache.hadoop.hdfs.MiniDFSCluster;
-import org.apache.hadoop.io.SequenceFile;
-import org.apache.hadoop.mapred.FileInputFormat;
-import org.apache.hadoop.mapred.FileOutputFormat;
-import org.apache.hadoop.mapred.JobConf;
-import org.apache.hadoop.util.ReflectionUtils;
-import org.junit.After;
-import org.junit.Before;
-import org.junit.Test;
-
-import edu.uci.ics.genomix.driver.Driver;
-import edu.uci.ics.genomix.driver.Driver.Plan;
-import edu.uci.ics.genomix.job.GenomixJob;
-import edu.uci.ics.genomix.type.KmerBytesWritable;
-import edu.uci.ics.genomix.type.KmerCountValue;
-
-@SuppressWarnings("deprecation")
-public class GraphBuildTest {
-    private static final String ACTUAL_RESULT_DIR = "graphbuildresult";
-    private static final String PATH_TO_HADOOP_CONF = "src/test/resources/hadoop/conf";
-
-    private static final String DATA_PATH = "data/testGeneFile";
-    private static final String HDFS_INPUT_PATH = "/test";
-    private static final String HDFS_OUTPUT_PATH = "/result";
-
-    private static final String DUMPED_RESULT = ACTUAL_RESULT_DIR + HDFS_OUTPUT_PATH + "/result.txt";
-    private static final String CONVERT_RESULT = ACTUAL_RESULT_DIR + "/graph_build_result.txt";
-    private static final String EXPECTED_PATH = "src/test/resources/expected/result2";
-
-    private static final String HADOOP_CONF_PATH = ACTUAL_RESULT_DIR + File.separator + "conf.xml";
-    private MiniDFSCluster dfsCluster;
-
-    private JobConf conf = new JobConf();
-    private int numberOfNC = 2;
-    private int numPartitionPerMachine = 1;
-
-    private Driver driver;
-
-    @Before
-    public void setUp() throws Exception {
-        cleanupStores();
-        edu.uci.ics.hyracks.hdfs.utils.HyracksUtils.init();
-        FileUtils.forceMkdir(new File(ACTUAL_RESULT_DIR));
-        FileUtils.cleanDirectory(new File(ACTUAL_RESULT_DIR));
-        startHDFS();
-
-        FileInputFormat.setInputPaths(conf, HDFS_INPUT_PATH);
-        FileOutputFormat.setOutputPath(conf, new Path(HDFS_OUTPUT_PATH));
-
-        conf.setInt(GenomixJob.KMER_LENGTH, 55);
-        driver = new Driver(edu.uci.ics.hyracks.hdfs.utils.HyracksUtils.CC_HOST,
-                edu.uci.ics.hyracks.hdfs.utils.HyracksUtils.TEST_HYRACKS_CC_CLIENT_PORT, numPartitionPerMachine);
-    }
-
-    private void cleanupStores() throws IOException {
-        FileUtils.forceMkdir(new File("teststore"));
-        FileUtils.forceMkdir(new File("build"));
-        FileUtils.cleanDirectory(new File("teststore"));
-        FileUtils.cleanDirectory(new File("build"));
-    }
-
-    private void startHDFS() throws IOException {
-        conf.addResource(new Path(PATH_TO_HADOOP_CONF + "/core-site.xml"));
-        conf.addResource(new Path(PATH_TO_HADOOP_CONF + "/mapred-site.xml"));
-        conf.addResource(new Path(PATH_TO_HADOOP_CONF + "/hdfs-site.xml"));
-
-        FileSystem lfs = FileSystem.getLocal(new Configuration());
-        lfs.delete(new Path("build"), true);
-        System.setProperty("hadoop.log.dir", "logs");
-        dfsCluster = new MiniDFSCluster(conf, numberOfNC, true, null);
-        FileSystem dfs = FileSystem.get(conf);
-        Path src = new Path(DATA_PATH);
-        Path dest = new Path(HDFS_INPUT_PATH);
-        dfs.mkdirs(dest);
-        dfs.copyFromLocalFile(src, dest);
-
-        DataOutputStream confOutput = new DataOutputStream(new FileOutputStream(new File(HADOOP_CONF_PATH)));
-        conf.writeXml(confOutput);
-        confOutput.flush();
-        confOutput.close();
-    }
-
-    private void cleanUpReEntry() throws IOException {
-        FileSystem lfs = FileSystem.getLocal(new Configuration());
-        if (lfs.exists(new Path(DUMPED_RESULT))) {
-            lfs.delete(new Path(DUMPED_RESULT), true);
-        }
-        FileSystem dfs = FileSystem.get(conf);
-        if (dfs.exists(new Path(HDFS_OUTPUT_PATH))) {
-            dfs.delete(new Path(HDFS_OUTPUT_PATH), true);
-        }
-    }
-
-    @Test
-    public void TestAll() throws Exception {
-        cleanUpReEntry();
-        TestPreClusterGroupby();
-    }
-
-    public void TestPreClusterGroupby() throws Exception {
-        conf.set(GenomixJob.GROUPBY_TYPE, "precluster");
-        //conf.set(GenomixJob.OUTPUT_FORMAT, "text");
-        System.err.println("Testing PreClusterGroupBy");
-        driver.runJob(new GenomixJob(conf), Plan.BUILD_DEBRUJIN_GRAPH, true);
-        Assert.assertEquals(true, checkResults(EXPECTED_PATH));
-    }
-
-    private boolean checkResults(String expectedPath) throws Exception {
-        String format = conf.get(GenomixJob.OUTPUT_FORMAT);
-        if ("text".equalsIgnoreCase(format)) {
-            FileUtil.copyMerge(FileSystem.get(conf), new Path(HDFS_OUTPUT_PATH),
-                    FileSystem.getLocal(new Configuration()), new Path(DUMPED_RESULT), false, conf, null);
-        } else {
-
-            FileSystem.getLocal(new Configuration()).mkdirs(new Path(ACTUAL_RESULT_DIR + HDFS_OUTPUT_PATH));
-            File filePathTo = new File(CONVERT_RESULT);
-            BufferedWriter bw = new BufferedWriter(new FileWriter(filePathTo));
-            for (int i = 0; i < numPartitionPerMachine * numberOfNC; i++) {
-                String partname = "/part-" + i;
-                FileUtil.copy(FileSystem.get(conf), new Path(HDFS_OUTPUT_PATH + partname),
-                        FileSystem.getLocal(new Configuration()), new Path(ACTUAL_RESULT_DIR + HDFS_OUTPUT_PATH
-                                + partname), false, conf);
-
-                Path path = new Path(HDFS_OUTPUT_PATH + partname);
-                FileSystem dfs = FileSystem.get(conf);
-                if (dfs.getFileStatus(path).getLen() == 0) {
-                    continue;
-                }
-                SequenceFile.Reader reader = new SequenceFile.Reader(dfs, path, conf);
-                KmerBytesWritable key = new KmerBytesWritable(conf.getInt(GenomixJob.KMER_LENGTH,
-                        GenomixJob.DEFAULT_KMER));
-                KmerCountValue value = (KmerCountValue) ReflectionUtils.newInstance(reader.getValueClass(), conf);
-
-                while (reader.next(key, value)) {
-                    if (key == null || value == null) {
-                        break;
-                    }
-                    bw.write(key.toString() + "\t" + value.toString());
-                    System.out.println(key.toString() + "\t" + value.toString());
-                    bw.newLine();
-                }
-                reader.close();
-            }
-            bw.close();
-        }
-
-        // TestUtils.compareWithSortedResult(new File(expectedPath), dumped);
-        return true;
-    }
-
-    @After
-    public void tearDown() throws Exception {
-        edu.uci.ics.hyracks.hdfs.utils.HyracksUtils.deinit();
-        cleanupHDFS();
-    }
-
-    private void cleanupHDFS() throws Exception {
-        dfsCluster.shutdown();
-    }
-}
diff --git a/genomix/genomix-pregelix/src/test/java/edu/uci/ics/genomix/pregelix/pathmerge/GraphBuildTestCase.java b/genomix/genomix-pregelix/src/test/java/edu/uci/ics/genomix/pregelix/pathmerge/GraphBuildTestCase.java
deleted file mode 100644
index daa7e39..0000000
--- a/genomix/genomix-pregelix/src/test/java/edu/uci/ics/genomix/pregelix/pathmerge/GraphBuildTestCase.java
+++ /dev/null
@@ -1,111 +0,0 @@
-package edu.uci.ics.genomix.pregelix.pathmerge;
-
-import java.io.BufferedWriter;
-import java.io.File;
-import java.io.FileWriter;
-import java.io.IOException;
-
-import junit.framework.Assert;
-import junit.framework.TestCase;
-
-import org.apache.hadoop.conf.Configuration;
-import org.apache.hadoop.fs.FileSystem;
-import org.apache.hadoop.fs.FileUtil;
-import org.apache.hadoop.fs.Path;
-import org.apache.hadoop.io.SequenceFile;
-import org.apache.hadoop.mapred.JobConf;
-import org.apache.hadoop.util.ReflectionUtils;
-import org.junit.Test;
-
-import edu.uci.ics.genomix.driver.Driver;
-import edu.uci.ics.genomix.driver.Driver.Plan;
-import edu.uci.ics.genomix.job.GenomixJob;
-import edu.uci.ics.genomix.type.KmerBytesWritable;
-import edu.uci.ics.genomix.type.KmerCountValue;
-
-public class GraphBuildTestCase extends TestCase {
-    private final JobConf conf;
-    private Driver driver;
-    private int numberOfNC = 2;
-    private int numPartitionPerMachine = 1;
-
-    private static final String ACTUAL_RESULT_DIR = "graphbuildresult";
-    private static final String HDFS_OUTPUT_PATH = "/result";
-    private static final String DUMPED_RESULT = ACTUAL_RESULT_DIR + HDFS_OUTPUT_PATH + "/result.txt";
-    private static final String CONVERT_RESULT = ACTUAL_RESULT_DIR + HDFS_OUTPUT_PATH + "/result.txt.txt";
-
-    public GraphBuildTestCase(JobConf conf, Driver driver) {
-        this.conf = conf;
-        this.driver = driver;
-    }
-
-    private void cleanUpReEntry() throws IOException {
-        FileSystem lfs = FileSystem.getLocal(new Configuration());
-        if (lfs.exists(new Path(DUMPED_RESULT))) {
-            lfs.delete(new Path(DUMPED_RESULT), true);
-        }
-        FileSystem dfs = FileSystem.get(conf);
-        if (dfs.exists(new Path(HDFS_OUTPUT_PATH))) {
-            dfs.delete(new Path(HDFS_OUTPUT_PATH), true);
-        }
-    }
-
-    @Test
-    public void Test() throws Exception {
-        cleanUpReEntry();
-        TestPreClusterGroupby();
-    }
-
-    public void TestPreClusterGroupby() throws Exception {
-        conf.set(GenomixJob.GROUPBY_TYPE, "precluster");
-        System.err.println("Testing PreClusterGroupBy");
-        driver.runJob(new GenomixJob(conf), Plan.BUILD_DEBRUJIN_GRAPH, true);
-        Assert.assertEquals(true, checkResults());
-    }
-
-    private boolean checkResults() throws Exception {
-        File dumped = null;
-        String format = conf.get(GenomixJob.OUTPUT_FORMAT);
-        if ("text".equalsIgnoreCase(format)) {
-            FileUtil.copyMerge(FileSystem.get(conf), new Path(HDFS_OUTPUT_PATH),
-                    FileSystem.getLocal(new Configuration()), new Path(DUMPED_RESULT), false, conf, null);
-            dumped = new File(DUMPED_RESULT);
-        } else {
-
-            FileSystem.getLocal(new Configuration()).mkdirs(new Path(ACTUAL_RESULT_DIR + HDFS_OUTPUT_PATH));
-            File filePathTo = new File(CONVERT_RESULT);
-            BufferedWriter bw = new BufferedWriter(new FileWriter(filePathTo));
-            for (int i = 0; i < numPartitionPerMachine * numberOfNC; i++) {
-                String partname = "/part-" + i;
-                FileUtil.copy(FileSystem.get(conf), new Path(HDFS_OUTPUT_PATH + partname),
-                        FileSystem.getLocal(new Configuration()), new Path(ACTUAL_RESULT_DIR + HDFS_OUTPUT_PATH
-                                + partname), false, conf);
-
-                Path path = new Path(HDFS_OUTPUT_PATH + partname);
-                FileSystem dfs = FileSystem.get(conf);
-                if (dfs.getFileStatus(path).getLen() == 0) {
-                    continue;
-                }
-                SequenceFile.Reader reader = new SequenceFile.Reader(dfs, path, conf);
-                KmerBytesWritable key = new KmerBytesWritable(conf.getInt(GenomixJob.KMER_LENGTH,
-                        GenomixJob.DEFAULT_KMER));
-                KmerCountValue value = (KmerCountValue) ReflectionUtils.newInstance(reader.getValueClass(), conf);
-
-                while (reader.next(key, value)) {
-                    if (key == null || value == null) {
-                        break;
-                    }
-                    bw.write(key.toString() + "\t" + value.toString());
-                    System.out.println(key.toString() + "\t" + value.toString());
-                    bw.newLine();
-                }
-                reader.close();
-            }
-            bw.close();
-            dumped = new File(CONVERT_RESULT);
-        }
-
-        // TestUtils.compareWithSortedResult(new File(expectedPath), dumped);
-        return true;
-    }
-}
diff --git a/genomix/genomix-pregelix/src/test/java/edu/uci/ics/genomix/pregelix/pathmerge/GraphBuildTestSuite.java b/genomix/genomix-pregelix/src/test/java/edu/uci/ics/genomix/pregelix/pathmerge/GraphBuildTestSuite.java
deleted file mode 100644
index fdc3785..0000000
--- a/genomix/genomix-pregelix/src/test/java/edu/uci/ics/genomix/pregelix/pathmerge/GraphBuildTestSuite.java
+++ /dev/null
@@ -1,127 +0,0 @@
-package edu.uci.ics.genomix.pregelix.pathmerge;
-
-import java.io.BufferedWriter;
-import java.io.DataOutputStream;
-import java.io.File;
-import java.io.FileOutputStream;
-import java.io.FileWriter;
-import java.io.IOException;
-
-import org.apache.commons.io.FileUtils;
-import org.apache.hadoop.conf.Configuration;
-import org.apache.hadoop.fs.FileSystem;
-import org.apache.hadoop.fs.FileUtil;
-import org.apache.hadoop.fs.Path;
-import org.apache.hadoop.hdfs.MiniDFSCluster;
-import org.apache.hadoop.io.SequenceFile;
-import org.apache.hadoop.mapred.FileInputFormat;
-import org.apache.hadoop.mapred.FileOutputFormat;
-import org.apache.hadoop.mapred.JobConf;
-import org.apache.hadoop.util.ReflectionUtils;
-
-import edu.uci.ics.genomix.driver.Driver;
-import edu.uci.ics.genomix.driver.Driver.Plan;
-import edu.uci.ics.genomix.job.GenomixJob;
-import edu.uci.ics.genomix.type.KmerBytesWritable;
-import edu.uci.ics.genomix.type.KmerCountValue;
-import junit.framework.Assert;
-import junit.framework.Test;
-import junit.framework.TestResult;
-import junit.framework.TestSuite;
-
-public class GraphBuildTestSuite extends TestSuite {
-    private static final String ACTUAL_RESULT_DIR = "graphbuildresult";
-    private static final String PATH_TO_HADOOP_CONF = "src/test/resources/hadoop/conf";
-
-    private static final String DATA_PATH = "graph/7/TreePath";
-    private static final String HDFS_INPUT_PATH = "/test";
-    private static final String HDFS_OUTPUT_PATH = "/result";
-
-    private static final String HADOOP_CONF_PATH = ACTUAL_RESULT_DIR + File.separator + "conf.xml";
-    private MiniDFSCluster dfsCluster;
-
-    private static JobConf conf = new JobConf();
-    private int numberOfNC = 2;
-    private int numPartitionPerMachine = 1;
-
-    private static Driver driver;
-
-    public void setUp() throws Exception {
-        cleanupStores();
-        edu.uci.ics.hyracks.hdfs.utils.HyracksUtils.init();
-        FileUtils.forceMkdir(new File(ACTUAL_RESULT_DIR));
-        FileUtils.cleanDirectory(new File(ACTUAL_RESULT_DIR));
-        startHDFS();
-
-        FileInputFormat.setInputPaths(conf, HDFS_INPUT_PATH);
-        FileOutputFormat.setOutputPath(conf, new Path(HDFS_OUTPUT_PATH));
-
-        conf.setInt(GenomixJob.KMER_LENGTH, 7);
-        driver = new Driver(edu.uci.ics.hyracks.hdfs.utils.HyracksUtils.CC_HOST,
-                edu.uci.ics.hyracks.hdfs.utils.HyracksUtils.TEST_HYRACKS_CC_CLIENT_PORT, numPartitionPerMachine);
-    }
-
-    private void cleanupStores() throws IOException {
-        FileUtils.forceMkdir(new File("teststore"));
-        FileUtils.forceMkdir(new File("build"));
-        FileUtils.cleanDirectory(new File("teststore"));
-        FileUtils.cleanDirectory(new File("build"));
-    }
-
-    private void startHDFS() throws IOException {
-        conf.addResource(new Path(PATH_TO_HADOOP_CONF + "/core-site.xml"));
-        conf.addResource(new Path(PATH_TO_HADOOP_CONF + "/mapred-site.xml"));
-        conf.addResource(new Path(PATH_TO_HADOOP_CONF + "/hdfs-site.xml"));
-
-        FileSystem lfs = FileSystem.getLocal(new Configuration());
-        lfs.delete(new Path("build"), true);
-        System.setProperty("hadoop.log.dir", "logs");
-        dfsCluster = new MiniDFSCluster(conf, numberOfNC, true, null);
-        FileSystem dfs = FileSystem.get(conf);
-        Path src = new Path(DATA_PATH);
-        Path dest = new Path(HDFS_INPUT_PATH);
-        dfs.mkdirs(dest);
-        dfs.copyFromLocalFile(src, dest);
-
-        DataOutputStream confOutput = new DataOutputStream(new FileOutputStream(new File(HADOOP_CONF_PATH)));
-        conf.writeXml(confOutput);
-        confOutput.flush();
-        confOutput.close();
-    }
-
-    public static Test suite() throws Exception {
-        GraphBuildTestSuite testSuite = new GraphBuildTestSuite();
-        testSuite.setUp();
-        testSuite.addTest(new GraphBuildTestCase(conf, driver));
-        return testSuite;
-    }
-
-    /**
-     * Runs the tests and collects their result in a TestResult.
-     */
-    @Override
-    public void run(TestResult result) {
-        try {
-            int testCount = countTestCases();
-            for (int i = 0; i < testCount; i++) {
-                // cleanupStores();
-                Test each = this.testAt(i);
-                if (result.shouldStop())
-                    break;
-                runTest(each, result);
-            }
-            tearDown();
-        } catch (Exception e) {
-            throw new IllegalStateException(e);
-        }
-    }
-
-    public void tearDown() throws Exception {
-        edu.uci.ics.hyracks.hdfs.utils.HyracksUtils.deinit();
-        cleanupHDFS();
-    }
-
-    private void cleanupHDFS() throws Exception {
-        dfsCluster.shutdown();
-    }
-}
diff --git a/genomix/genomix-pregelix/src/test/java/edu/uci/ics/genomix/pregelix/pathmerge/MergePathTest.java b/genomix/genomix-pregelix/src/test/java/edu/uci/ics/genomix/pregelix/pathmerge/MergePathTest.java
index 68c186a..8c02547 100644
--- a/genomix/genomix-pregelix/src/test/java/edu/uci/ics/genomix/pregelix/pathmerge/MergePathTest.java
+++ b/genomix/genomix-pregelix/src/test/java/edu/uci/ics/genomix/pregelix/pathmerge/MergePathTest.java
@@ -14,7 +14,6 @@
 
 import edu.uci.ics.genomix.pregelix.io.ValueStateWritable;
 import edu.uci.ics.genomix.pregelix.type.State;
-import edu.uci.ics.genomix.type.GeneCode;
 import edu.uci.ics.genomix.type.KmerBytesWritable;
 
 public class MergePathTest {
@@ -98,10 +97,10 @@
                 if (key == null || value == null) {
                     break;
                 }
-                if (value.getLengthOfMergeChain() <= maxLength && value.getLengthOfMergeChain() != kmerSize) {
+                /*if (value.getLengthOfMergeChain() <= maxLength && value.getLengthOfMergeChain() != kmerSize) {
                     bw.write(value.getLengthOfMergeChain() + "\t" + value.getMergeChain().toString());
                     bw.newLine();
-                }
+                }*/
             }
             reader.close();
         }
@@ -123,10 +122,10 @@
                 if (key == null || value == null) {
                     break;
                 }
-                if (value.getLengthOfMergeChain() <= maxLength && value.getState() == State.FINAL_VERTEX) {
+               /* if (value.getLengthOfMergeChain() <= maxLength && value.getState() == State.FINAL_VERTEX) {
                     bw.write(value.getLengthOfMergeChain() + "\t" + value.getMergeChain().toString());
                     bw.newLine();
-                }
+                }*/
             }
             reader.close();
         }