public void generateFakeDoc(_ParentDoc pDoc, File folder, int docLength, HashMap<Integer, Double>wordSstat, ArrayList<Integer>widList, int docIndex){
		String fakeDocName = docIndex+".txt";
		
		try{
			
			PrintWriter pw = new PrintWriter(new File(folder, fakeDocName));
			
			for(_SparseFeature sf:pDoc.getSparse()){
				int wid = sf.getIndex();
				double val = sf.getValue();
				for(int i=0; i<val; i++){
					pw.print(wid);
					pw.print("\t");
				}
			}
			
			for(int i=0; i<docLength; i++){
				int wid = generateFakeWord(wordSstat, widList);
//				System.out.println(wid+"wordId");
				pw.print(wid);
				pw.print("\t");
			}
			
			pw.flush();
			pw.close();
		}catch(Exception e){
			e.printStackTrace();
		}
	}