diff --git a/buzz_scripts/graphform.bzz b/buzz_scripts/graphform.bzz
new file mode 100644
index 0000000..cfb5b5d
--- /dev/null
+++ b/buzz_scripts/graphform.bzz
@@ -0,0 +1,816 @@
+#
+# Include files
+#
+include "string.bzz"
+include "vec2.bzz"
+include "update.bzz"
+include "barrier.bzz"	# don't use a stigmergy id=11 with this header.
+include "uavstates.bzz"	# require an 'action' function to be defined here.
+
+include "shapes.bzz"
+
+ROBOT_RADIUS=50
+ROBOT_DIAMETER=2.0*ROBOT_RADIUS
+ROBOT_SAFETYDIST=2.0*ROBOT_DIAMETER
+
+#
+# Global variables
+#
+
+#
+#Save message from all neighours
+#the indexes are as 1,2,3..., while each value is a table that store the information of a neighbour robot
+m_MessageState={}#store received neighbour message
+m_MessageLable={}#store received neighbour message
+m_MessageReqLable={}#store received neighbour message
+m_MessageReqID={}#store received neighbour message
+m_MessageResponse={}#store received neighbour message
+m_MessageRange={}#store received neighbour message
+m_MessageBearing={}#store received neighbour message
+m_neighbourCunt=0#used to cunt neighbours
+#Save message from one neighbour
+#the indexes are as State(received state),Lable(received lable),ReqLable,ReqID,Response,Range,Bearing
+m_receivedMessage={.State=s2i("STATE_FREE"),.Lable=0,.ReqLable=0,.ReqID=0,.Response=r2i("REQ_NONE"),.Range=0,.Bearing=0}
+
+#
+#Save the message to send
+#The keys of the talbe is State(current state),Lable(current lable),ReqLable(requested lable),ReqID(request id),Response(reply message{REQ_NONE,REQ_GRANTED,REQ_RESEND})
+m_selfMessage={.State=s2i("STATE_FREE"),.Lable=0,.ReqLable=0,.ReqID=0,.Response=r2i("REQ_NONE")}
+
+#Current robot state
+m_eState="STATE_FREE"
+
+#navigation vector
+m_navigation={.x=0,.y=0}
+
+#Debug message to be displayed in qt-opengl
+#m_ossDebugMsg
+
+#Debug vector to draw
+#CVector2 m_cDebugVector
+
+#Current label being requested or chosen (-1 when none)
+m_nLabel=-1
+
+#Label request id
+m_unRequestId=0
+
+#Global bias, used to map local coordinate to global coordinate
+m_bias=0
+
+#Vector to predecessor,range is the distance between robots, bearing is the angle of pred wrt self in local coordinate of self, globalbearing is the angle of self wrt pred in global coordinate
+m_cMeToPred={.Range=0.0,.Bearing=0.0,.GlobalBearing=0.0}
+
+#Counter to wait for something to happen
+m_unWaitCount=0
+
+#Number of steps to wait before looking for a free label
+m_unLabelSearchWaitTime=0
+
+#Number of steps to wait for an answer to be received
+m_unResponseTimeThreshold=0
+
+#Number of steps to wait until giving up joining
+m_unJoiningLostPeriod=0
+
+#Tolerance distance to a target location
+m_fTargetDistanceTolerance=0
+
+#step cunt
+step_cunt=0
+
+#virtual stigmergy
+v_tag = stigmergy.create(1)
+
+# Lennard-Jones parameters, may need change
+EPSILON    = 13.5 #the LJ parameter for other robots
+EPSILON_FOR1 = 10.0 #the LJ parameter for the robot labeled 1
+
+# Lennard-Jones interaction magnitude
+
+function FlockInteraction(dist,target,epsilon){
+	var mag = -(epsilon / dist) * ((target / dist)^4 - (target / dist)^2)
+	return mag
+}
+
+function LimitAngle(angle){
+	if(angle>2*math.pi)
+		return angle-2*math.pi
+	else if (angle<0)
+		return angle+2*math.pi
+	else
+		return angle
+}
+
+#
+# Calculates the angle of the given vector2.
+# PARAM v: The vector2.
+# RETURN: The angle of the vector.
+#
+Angle = function(v) {
+  return math.atan(v.y, v.x)
+}
+
+#
+#return the number of value in table
+#
+function count(table,value){
+	var number=0
+	var i=0
+	while(i<size(table)){
+		if(table[i]==value){
+			number=number+1
+		}
+		i=i+1
+	}
+	return number
+}
+
+#map from int to state
+function i2s(value){
+	if(value==1){
+	return "STATE_FREE"
+	}
+	else if(value==2){
+	return "STATE_ASKING"
+	}
+	else if(value==3){
+	return "STATE_JOINING"
+	}
+	else if(value==4){
+	return "STATE_JOINED"
+	}
+	else if(value==5){
+	return "STATE_LOCK"
+	}
+}
+
+#map from state to int
+function s2i(value){
+	if(value=="STATE_FREE"){
+	return 1
+	}
+	else if(value=="STATE_ASKING"){
+	return 2
+	}
+	else if(value=="STATE_JOINING"){
+	return 3
+	}
+	else if(value=="STATE_JOINED"){
+	return 4
+	}
+	else if(value=="STATE_LOCK"){
+	return 5
+	}
+}
+#map form int to response
+function i2r(value){
+	if(value==1){
+	return "REQ_NONE"
+	}
+	else if(value==2){
+	return "REQ_GRANTED"
+	}
+
+}
+#map from response to int
+function r2i(value){
+	if(value=="REQ_NONE"){
+	return 1
+	}
+	else if(value=="REQ_GRANTED"){
+	return 2
+	}
+}
+
+
+#
+#return the index of value
+#
+function find(table,value){
+	var index=nil
+	var i=0
+	while(i<size(table)){
+		if(table[i]==value)
+			index=i
+		i=i+1
+	}
+	return index
+}
+
+function pow(base,exponent){
+	var i=0
+	var renturn_val=1
+	if(exponent==0)
+		return 1
+	else{
+		while(i<exponent){
+			renturn_val=renturn_val*base
+			i=i+1
+		}
+		return renturn_val
+	}
+}
+
+
+function start_listen(){
+neighbors.listen("m",
+    function(vid,value,rid){
+    #store the received message
+    var temp_id=rid
+    m_receivedMessage.State=i2s(value.State)
+    m_receivedMessage.Lable=value.Lable
+    m_receivedMessage.ReqLable=value.ReqLable
+    m_receivedMessage.ReqID=value.ReqID
+    m_receivedMessage.Response=i2r(value.Response)
+    Get_DisAndAzi(temp_id)
+    #add the received message
+    #
+    m_MessageState[m_neighbourCunt]=i2s(value.State)
+    m_MessageLable[m_neighbourCunt]=value.Lable
+    m_MessageReqLable[m_neighbourCunt]=value.ReqLable
+    m_MessageReqID[m_neighbourCunt]=value.ReqID
+    m_MessageResponse[m_neighbourCunt]=i2r(value.Response)
+    m_MessageRange[m_neighbourCunt]=m_receivedMessage.Range
+    m_MessageBearing[m_neighbourCunt]=m_receivedMessage.Bearing
+    m_neighbourCunt=m_neighbourCunt+1
+})
+}
+#
+#Function used to get the station info of the sender of the message
+function Get_DisAndAzi(id){
+	neighbors.foreach(
+	function(rid, data) {
+		if(rid==id){
+		m_receivedMessage.Range=data.distance*100.0
+		m_receivedMessage.Bearing=data.azimuth
+		}
+		})
+}
+
+#
+#Update node info according to neighbour robots
+#
+function UpdateNodeInfo(){
+	#Collect informaiton
+	#Update information
+	var i=0
+
+	while(i<m_neighbourCunt){
+		if(m_MessageState[i]=="STATE_JOINED"){
+			m_vecNodes[m_MessageLable[i]].State="ASSIGNED"
+			m_vecNodes[m_MessageLable[i]].StateAge=m_unJoiningLostPeriod
+		}
+		else if(m_MessageState[i]=="STATE_JOINING"){
+			m_vecNodes[m_MessageLable[i]].State="ASSIGNING"
+			m_vecNodes[m_MessageLable[i]].StateAge=m_unJoiningLostPeriod
+		}
+		i=i+1
+	}
+	#Forget old information
+	i=0
+	while(i<size(m_vecNodes)){
+		if((m_vecNodes[i].StateAge>0) and (m_vecNodes[i].State=="ASSIGNING")){
+		m_vecNodes[i].StateAge=m_vecNodes[i].StateAge-1
+		if(m_vecNodes[i].StateAge==0)
+			m_vecNodes[i].State="UNASSIGNED"
+		}
+	i=i+1
+	}
+}
+
+#
+#Transistion to state free
+#
+function TransitionToFree(){
+	m_eState="STATE_FREE"
+	m_unWaitCount=m_unLabelSearchWaitTime
+	m_selfMessage.State=s2i(m_eState)
+}
+
+#
+#Transistion to state asking
+#
+function TransitionToAsking(un_label){
+	m_eState="STATE_ASKING"
+	m_nLabel=un_label
+	m_unRequestId=rng.uniform(0,65536)+id#don't know why the random numbers are the same, add id to make the ReqID different
+	m_selfMessage.State=s2i(m_eState)
+	m_selfMessage.ReqLable=m_nLabel
+	m_selfMessage.ReqID=m_unRequestId
+
+	m_unWaitCount=m_unResponseTimeThreshold
+}
+
+#
+#Transistion to state joining
+#
+function TransitionToJoining(){
+	m_eState="STATE_JOINING"
+	m_selfMessage.State=s2i(m_eState)
+	m_selfMessage.Lable=m_nLabel
+	m_unWaitCount=m_unJoiningLostPeriod
+
+	neighbors.listen("r",
+		function(vid,value,rid){
+		#store the received message
+		if(value.Label==m_nLabel){
+		m_cMeToPred.GlobalBearing=value.Bearing
+
+		}
+	})
+
+}
+
+#
+#Transistion to state joined
+#
+function TransitionToJoined(){
+	m_eState="STATE_JOINED"
+	m_selfMessage.State=s2i(m_eState)
+	m_selfMessage.Lable=m_nLabel
+	m_vecNodes[m_nLabel].State="ASSIGNED"
+	neighbors.ignore("r")
+
+	#write statues
+	v_tag.put(m_nLabel, 1)
+
+	m_navigation.x=0.0
+	m_navigation.y=0.0
+	uav_moveto(m_navigation.x/100.0,m_navigation.y/100.0)
+}
+
+#
+#Transistion to state Lock, lock the current formation
+#
+function TransitionToLock(){
+	m_eState="STATE_LOCK"
+	m_selfMessage.State=s2i(m_eState)
+	m_selfMessage.Lable=m_nLabel
+	m_vecNodes[m_nLabel].State="ASSIGNED"
+
+	m_navigation.x=0.0
+	m_navigation.y=0.0
+	uav_moveto(m_navigation.x/100.0,m_navigation.y/100.0)
+}
+
+#
+# Do free
+#
+function DoFree() {
+	m_selfMessage.State=s2i(m_eState)
+
+	#wait for a while before looking for a lable
+	if(m_unWaitCount>0)
+		m_unWaitCount=m_unWaitCount-1
+
+	#find a set of joined robots
+	var setJoinedLables={}
+	var setJoinedIndexes={}
+	var i=0
+	var j=0
+	while(i<m_neighbourCunt){
+		if(m_MessageState[i]=="STATE_JOINED"){
+		setJoinedLables[j]=m_MessageLable[i]
+		setJoinedIndexes[j]=i
+		j=j+1
+		}
+		i=i+1
+	}
+
+	#go through the graph to look for a proper lable
+	var unFoundLable=0
+	var IDofPred=0
+	i=1
+	while(i<size(m_vecNodes) and (unFoundLable==0)){
+		#if the node is unassigned and the predecessor is insight
+		if(m_vecNodes[i].State=="UNASSIGNED" and count(setJoinedLables,m_vecNodes[i].Pred)==1){
+			unFoundLable=m_vecNodes[i].Lable
+			IDofPred=find(m_MessageLable,m_vecNodes[unFoundLable].Pred)
+		}
+		i=i+1
+	}
+
+	if(unFoundLable>0){
+		TransitionToAsking(unFoundLable)
+		return
+	}
+
+	#navigation
+	#if there is a joined robot within sight, move around joined robots
+	#else, gather with other free robots
+	if(size(setJoinedIndexes)>0){
+		var tempvec_P={.x=0.0,.y=0.0}
+		var tempvec_N={.x=0.0,.y=0.0}
+		i=0
+		while(i<size(setJoinedIndexes)){
+			var index=setJoinedIndexes[i]
+			tempvec_P=math.vec2.add(tempvec_P,math.vec2.newp(m_MessageRange[index],m_MessageBearing[index]+0.5*math.pi))
+			tempvec_N=math.vec2.add(tempvec_N,math.vec2.newp(m_MessageRange[index]-5.0*ROBOT_SAFETYDIST,m_MessageBearing[index]))
+			i=i+1
+		}
+		tempvec_P=math.vec2.scale(tempvec_P,size(setJoinedIndexes))
+		tempvec_N=math.vec2.scale(tempvec_N,size(setJoinedIndexes))
+		m_navigation=math.vec2.add(tempvec_P,tempvec_N)
+		uav_moveto(m_navigation.x/100.0,m_navigation.y/100.0)
+	}else{ #no joined robots in sight
+		i=0
+		var tempvec={.x=0.0,.y=0.0}
+
+		while(i<m_neighbourCunt){
+			tempvec=math.vec2.add(tempvec,math.vec2.newp(m_MessageRange[i]-2.0*ROBOT_SAFETYDIST,m_MessageBearing[i]))
+			i=i+1
+		}
+		m_navigation=math.vec2.scale(tempvec,1.0/i)
+		uav_moveto(m_navigation.x/100.0,m_navigation.y/100.0)
+	}
+
+
+
+	#jump the first step
+	if(step_cunt<=1){
+		uav_moveto(0.0,0.0)
+	}
+	#set message
+	m_selfMessage.State=s2i(m_eState)
+
+}
+
+
+
+
+#
+#Do asking
+#
+function DoAsking(){
+	#look for response from predecessor
+	var i=0
+	var psResponse=-1
+	while(i<m_neighbourCunt and psResponse==-1){
+		#the respond robot in joined state
+		#the request lable be the same as requesed
+		#get a respond
+		if(m_MessageState[i]=="STATE_JOINED"){
+			if(m_MessageReqLable[i]==m_nLabel)
+				if(m_MessageResponse[i]!="REQ_NONE"){
+				psResponse=i
+		}}
+		i=i+1
+	}
+	#analyse response
+	if(psResponse==-1){
+		#no response, wait
+		m_unWaitCount=m_unWaitCount-1
+		m_selfMessage.State=s2i(m_eState)
+		m_selfMessage.ReqLable=m_nLabel
+		m_selfMessage.ReqID=m_unRequestId
+		if(m_unWaitCount==0){
+			TransitionToFree()
+			return
+		}
+	}
+	else{
+	if(m_MessageReqID[psResponse]!=m_unRequestId)
+		TransitionToFree()
+	if(m_MessageReqID[psResponse]==m_unRequestId){
+		if(m_MessageResponse[psResponse]=="REQ_GRANTED"){
+			TransitionToJoining()
+			#TransitionToJoined()
+			return
+		}
+		else{
+			TransitionToAsking(m_nLabel)
+			return
+		}
+	}
+	}
+	uav_moveto(0.0,0.0)
+}
+
+#
+#Do joining
+#
+function DoJoining(){
+	#get information of pred
+	var i=0
+	var IDofPred=-1
+	while(i<m_neighbourCunt and IDofPred==-1){
+		if(m_MessageLable[i]==m_vecNodes[m_nLabel].Pred and m_MessageState[i]=="STATE_JOINED")
+			IDofPred=i
+		i=i+1
+	}
+
+	#found pred
+	if(IDofPred!=-1){
+		m_unWaitCount=m_unJoiningLostPeriod#if see pred, reset the timer
+
+		var P2Target=math.vec2.newp(m_vecNodes[m_nLabel].distance,m_vecNodes[m_nLabel].bearing)
+		m_cMeToPred.Range=m_MessageRange[IDofPred]#the poition of self to pred in local coordinate
+		m_cMeToPred.Bearing=m_MessageBearing[IDofPred]
+
+		#attention, m_cMeToPred.GlobalBearing is the bearing of self wrt pred in global coordinate
+		var S2PGlobalBearing=0
+
+		m_cMeToPred.GlobalBearing=LimitAngle(m_cMeToPred.GlobalBearing)
+
+		if(m_cMeToPred.GlobalBearing>math.pi)
+			S2PGlobalBearing=m_cMeToPred.GlobalBearing-math.pi
+		else
+			S2PGlobalBearing=m_cMeToPred.GlobalBearing+math.pi
+
+		var S2Pred=math.vec2.newp(m_cMeToPred.Range,S2PGlobalBearing)
+
+		#the vector from self to target in global coordinate
+		var S2Target=math.vec2.add(S2Pred,P2Target)
+		#change the vector to local coordinate of self
+		var S2Target_bearing=Angle(S2Target)
+		m_bias=m_cMeToPred.Bearing-S2PGlobalBearing
+		S2Target_bearing=S2Target_bearing+m_bias # commented out by DS'06/17
+		m_navigation=math.vec2.newp(math.vec2.length(S2Target),S2Target_bearing)
+		uav_moveto(m_navigation.x/100.0,m_navigation.y/100.0)
+
+
+
+		#test if is already in desired position
+		if(math.abs(S2Target.x)<m_fTargetDistanceTolerance and math.abs(S2Target.y)<m_fTargetDistanceTolerance){
+			#log(S2Target_dis,S2Target_bearing)
+			TransitionToJoined()
+			return
+		}
+	} else{ #miss pred, there is a change the another robot block the sight, keep moving as before for sometime
+		m_unWaitCount=m_unWaitCount-1
+	}
+
+
+	if(m_unWaitCount==0){
+		TransitionToFree()
+		return
+	}
+
+	#pack the communication package
+	m_selfMessage.State=s2i(m_eState)
+	m_selfMessage.Lable=m_nLabel
+
+}
+
+#
+#Do joined
+#
+function DoJoined(){
+	m_selfMessage.State=s2i(m_eState)
+	m_selfMessage.Lable=m_nLabel
+
+	#collect all requests
+	var mapRequests={}
+	var i=0
+	var j=0
+	var ReqLable
+	var JoiningLable
+	var seenPred=0
+	while(i<m_neighbourCunt){
+		if(m_MessageState[i]=="STATE_ASKING"){
+			ReqLable=m_MessageReqLable[i]
+			if(m_vecNodes[ReqLable].State=="UNASSIGNED")
+				if(m_nLabel==m_vecNodes[ReqLable].Pred){
+					#is a request, store the index
+					mapRequests[j]=i
+					j=j+1
+				}
+		}
+		if(m_MessageState[i]=="STATE_JOINING"){
+			JoiningLable=m_MessageLable[i]
+			if(m_nLabel==m_vecNodes[JoiningLable].Pred){
+				##joining wrt this dot,send the global bearing
+				var m_messageForJoining={.Label=JoiningLable,.Bearing=m_MessageBearing[i]-m_bias}
+				neighbors.broadcast("r",m_messageForJoining)
+			}
+		}
+		#if it is the pred
+		if(m_MessageState[i]=="STATE_JOINED" and m_MessageLable[i]==m_vecNodes[m_nLabel].Pred){
+			seenPred=1
+			m_unWaitCount=m_unJoiningLostPeriod
+		}
+		i=i+1
+	}
+
+	#get request
+	if(size(mapRequests)!=0){
+		i=1
+		var ReqIndex=0
+		while(i<size(mapRequests)){
+			#compare the distance
+			if(m_MessageRange[mapRequests[ReqIndex]]>m_MessageRange[mapRequests[i]])
+				ReqIndex=i
+			i=i+1
+		}
+		#get the best index, whose Reqlable and Reqid are
+		ReqLable=m_MessageReqLable[mapRequests[ReqIndex]]
+		var ReqID=m_MessageReqID[mapRequests[ReqIndex]]
+		m_selfMessage.ReqLable=ReqLable
+		m_selfMessage.ReqID=ReqID
+		m_selfMessage.Response=r2i("REQ_GRANTED")
+	}
+
+	#lost pred, wait for some time and transit to free
+	#if(seenPred==0){
+	#m_unWaitCount=m_unWaitCount-1
+	#if(m_unWaitCount==0){
+	#TransitionToFree()
+	#return
+	#}
+	#}
+
+
+	m_navigation.x=0.0
+	m_navigation.y=0.0
+	uav_moveto(m_navigation.x/100.0,m_navigation.y/100.0)
+
+
+	#check if should to transists to lock
+
+
+#	if(v_tag.size()==ROBOTS){
+#		TransitionToLock()
+#	}
+}
+
+#
+#Do Lock
+#
+function DoLock(){
+m_selfMessage.State=s2i(m_eState)
+m_selfMessage.Lable=m_nLabel
+
+m_navigation.x=0.0
+m_navigation.y=0.0
+
+#collect preds information
+var i=0
+var mypred1={.range=0,.bearing=0}
+var mypred2={.range=0,.bearing=0}
+
+while(i<m_neighbourCunt){
+
+	#is the first predecessor
+	if(m_MessageLable[i]==m_vecNodes_fixed[m_nLabel].Pred1){
+		mypred1.range=m_MessageRange[i]
+		mypred1.bearing=m_MessageBearing[i]
+	}
+	#is the second predecessor
+	if(m_MessageLable[i]==m_vecNodes_fixed[m_nLabel].Pred2){
+		mypred2.range=m_MessageRange[i]
+		mypred2.bearing=m_MessageBearing[i]
+	}
+i=i+1
+}
+
+#calculate motion vection
+if(m_nLabel==0){
+	m_navigation.x=0.0#change value so that robot 0 will move
+	m_navigation.y=0.0
+	log(";",m_nLabel,";",0)
+}
+
+if(m_nLabel==1){
+	var tempvec={.Range=0.0,.Bearing=0.0}
+	tempvec.Range=FlockInteraction(mypred1.range,m_vecNodes_fixed[m_nLabel].d1,EPSILON_FOR1)
+	#tempvec.Range=mypred1.range-m_vecNodes_fixed[m_nLabel].d1
+	tempvec.Bearing=mypred1.bearing
+	m_navigation=math.vec2.newp(tempvec.Range,tempvec.Bearing)
+	log(";",m_nLabel,";",mypred1.range-m_vecNodes_fixed[m_nLabel].d1)
+}
+if(m_nLabel>1){
+	var cDir={.x=0.0,.y=0.0}
+	var cDir1={.x=0.0,.y=0.0}
+	var cDir2={.x=0.0,.y=0.0}
+	cDir1=math.vec2.newp(FlockInteraction(mypred1.range,m_vecNodes_fixed[m_nLabel].d1,EPSILON),mypred1.bearing)
+	cDir2=math.vec2.newp(FlockInteraction(mypred2.range,m_vecNodes_fixed[m_nLabel].d2,EPSILON),mypred2.bearing)
+	#cDir1=math.vec2.newp((mypred1.range-m_vecNodes_fixed[m_nLabel].d1),mypred1.bearing)
+	#cDir2=math.vec2.newp((mypred2.range-m_vecNodes_fixed[m_nLabel].d2),mypred2.bearing)
+	cDir=math.vec2.add(cDir1,cDir2)
+
+	cDir=math.vec2.scale(cDir,5)
+	m_navigation.x=cDir.x
+	m_navigation.y=cDir.y
+	#log(m_nLabel,"error:",mypred1.range-m_vecNodes_fixed[m_nLabel].d1,"and",mypred2.range-m_vecNodes_fixed[m_nLabel].d2)
+	log(";",m_nLabel,";",mypred1.range-m_vecNodes_fixed[m_nLabel].d1)
+}
+#move
+uav_moveto(m_navigation.x/100.0,m_navigation.y/100.0)
+}
+
+function action(){
+  statef=action
+  UAVSTATE="GRAPH"
+}
+
+#
+# Executed at init
+#
+function init() {
+	#
+	#Adjust parameters here
+	#
+	m_unResponseTimeThreshold=10
+	m_unLabelSearchWaitTime=10
+	m_fTargetDistanceTolerance=10
+	m_unJoiningLostPeriod=100
+
+	#
+	# Join Swarm
+	#
+	uav_initswarm()
+	Reset();
+}
+
+#
+# Executed every step
+#
+function step(){
+	uav_rccmd()
+	uav_neicmd()
+	#update the graph
+	UpdateNodeInfo()
+	#reset message package to be sent
+	m_selfMessage={.State=s2i("STATE_FREE"),.Lable=0,.ReqLable=0,.ReqID=0,.Response=r2i("REQ_NONE")}
+	#
+	#act according to current state
+	#
+	if(UAVSTATE=="GRAPH"){
+		if(m_eState=="STATE_FREE")
+			DoFree()
+		else if(m_eState=="STATE_ESCAPE")
+			DoEscape()
+		else if(m_eState=="STATE_ASKING")
+			DoAsking()
+		else if(m_eState=="STATE_JOINING")
+			DoJoining()
+		else if(m_eState=="STATE_JOINED")
+			DoJoined()
+		else if(m_eState=="STATE_LOCK")
+			DoLock()
+	}
+
+	statef()
+
+
+	debug(m_eState,m_nLabel)
+	log("Current state: ", UAVSTATE)
+	log("Swarm size: ", ROBOTS)
+	#navigation
+
+	#broadcast messag
+	neighbors.broadcast("m",m_selfMessage)
+
+	#
+	#clean message storage
+	m_MessageState={}#store received neighbour message
+	m_MessageLable={}#store received neighbour message
+	m_MessageReqLable={}#store received neighbour message
+	m_MessageReqID={}#store received neighbour message
+	m_MessageResponse={}#store received neighbour message
+	m_MessageRange={}#store received neighbour message
+	m_MessageBearing={}#store received neighbour message
+	m_neighbourCunt=0
+
+
+	#step cunt+1
+	step_cunt=step_cunt+1
+}
+
+#
+# Executed when reset
+#
+function Reset(){
+    #m_vecNodes={}
+    #m_vecNodes = parse_graph("/home/dave/ROS_WS/src/rosbuzz/buzz_scripts/include/Graph_drone.graph")#change the .graph file when necessary
+    m_vecNodes_fixed={}
+    m_vecNodes_fixed=parse_graph_fixed("/home/dave/ROS_WS/src/rosbuzz/buzz_scripts/include/Graph_fixed.graph")
+    m_nLabel=-1
+
+	#start listening
+	start_listen()
+	#
+	#set initial state, only one robot choose [A], while the rest choose [B]
+	#
+	#[A]The robot used to triger the formation process is defined as joined,
+	if(id==0){
+		m_nLabel=0
+		TransitionToJoined()
+	}
+	#[B]Other robots are defined as free.
+	else{
+		TransitionToFree()
+	}
+}
+
+#
+# Executed upon destroy
+#
+function destroy() {
+	#clear neighbour message
+	uav_moveto(0.0,0.0)
+	m_vecNodes={}
+	#stop listening
+	neighbors.ignore("m")
+}