void accPhiStat(_Doc d) {
			double prob;
			for(int t=0; t<d.getSenetenceSize(); t++) {
				_Stn s = d.getSentence(t);
				for(_SparseFeature f:s.getFv()) {
					int wid = f.getIndex();
					double v = f.getValue();//frequency
					for(int i=0; i<number_of_topics; i++) {
						prob = this.p_dwzpsi[t][i];
						for(int j=1; j<constant; j++)
							prob += this.p_dwzpsi[t][i + j*number_of_topics];
						this.sstat[i][wid] += v * prob;
					}
				}
			}
		}