java 矩阵乘法的mapreduce程序实现

java 矩阵乘法的mapreduce程序实现

map函数：对于矩阵M中的每个元素m(ij)，产生一系列的key-value对<(i，k)，（M，j，m(ij)）>

其中k=1,2.....知道矩阵N的总列数;对于矩阵N中的每个元素n(jk)，产生一系列的key-value对<(i , k) , (N , j ,n(jk)>, 其中i=1,2.......直到i=1,2.......直到矩阵M的总列数。

map

package com.cb.matrix;import static org.mockito.Matchers.intThat;import java.io.IOException;import org.apache.hadoop.conf.Configuration;import org.apache.hadoop.io.Text;import org.apache.hadoop.mapred.FileSplit;import org.apache.hadoop.mapReduce.Mapper;import com.sun.org.apache.bcel.internal.generic.NEW;public class MatrixMapper extends Mapper<Object, Text, Text, Text> { private Text map_key=new Text(); private Text map_value= new Text(); private int columnN; private int rowM;   @Override protected void setup(Mapper<Object, Text, Text, Text>.Context context) throws IOException, InterruptedException { // TODO Auto-generated method stub Configuration config=context.getConfiguration(); columnN=Integer.parseInt(config.get("columnN")); rowM =Integer.parseInt(config.get("rowM")); }  @Override protected void map(Object key, Text value, Mapper<Object, Text, Text, Text>.Context context)  throws IOException, InterruptedException { // TODO Auto-generated method stub //得到文件名，从而区分输入矩阵M和N FileSplit fileSplit=(FileSplit)context.getInputSplit(); String fileName=fileSplit.getPath().getName();  if (fileName.contains("M")) {  String[] tuple =value.toString().split(",");  int i =Integer.parseInt(tuple[0]);  String[] tuples=tuple[1].split("\t");  int j=Integer.parseInt(tuples[0]);  int Mij=Integer.parseInt(tuples[1]);  for(int k=1;k<columnN+1;k++){  map_key.set(i+","+k);  map_value.set("M"+","+j+","+Mij);  context.write(map_key, map_value);  }   } else if(fileName.contains("N")){  String[] tuple=value.toString().split(",");  int j=Integer.parseInt(tuple[0]);  String[] tuples =tuple[1].split("\t");  int k=Integer.parseInt(tuples[0]);  int Njk=Integer.parseInt(tuples[1]);  for(int i=1;i<rowM+1;i++){  map_key.set(i+","+k);  map_value.set("N"+","+j+","+Njk);  context.write(map_key, map_value);  } }  }}