public void gaussanClassify()
	{
		//call function to create requestlist
		createRequestList();
		//first normalize the lifetime of each workload so that its lifetime is in (0,1)
		//sort the requestList in ascending order of the lifetime of VM
		Collections.sort(this.getRequestList(), new Comparator<Request>() {
			@Override
			public int compare(Request o1, Request o2) {
				
				Long o1LifeTime=new Long(o1.getDuration());
				
				Long o2LifeTime=new Long(o2.getDuration()); 
				return(o1LifeTime.compareTo(o2LifeTime));
				
			}
			
		});
		
		long minDuration=this.getRequestList().get(0).getDuration();
		long maxDuration=this.getRequestList().get(this.getRequestList().size()-1).getDuration();
		
		// second, classify the requests 
		for(Request re: this.getRequestList())
		{
			double duration=(double)(re.getDuration()-minDuration)/(maxDuration-minDuration);
			if(duration>=0 && duration<=0.25)
			{
				re.setType(RequestType.SPOT);
			}else if(duration>0.25 && duration<=0.5){
				re.setType(RequestType.ONDEMAND);
			}else if(duration>0.5 && duration<=1)
			{
				re.setType(RequestType.RESERVED);
			}
			addNewWorkloadtoList(re);
			
		}
		
	}