The reducer of forward propagation part in deep learning MapReduce program

/*
 * Project Name: Deep learning based on Hadoop (MapReduce)
 * 
 * Class Description: 
 * 	This is the reducer of forward propagation part in deep learning MapReduce program.
 *  The task of this MapReduce is to compute the input of next layer using the input 
 *  from lower layer and the weights just computed. 
 *  
 *  Each reducer collects the <testCaseID, testCaseContent> pair, and output it directly.
 * 
 * 
 * Author: Kairan Sun
 * Last Update Date: Nov. 30, 2013 
 */