title: mapreduce matrix multiplication with hadoop
body: <p>I am trying to run the matrix multiplication example mentioned(with source code) on the following link:</p>
  
  <p><a href="http://www.norstad.org/matrix-multiply/index.html" rel="nofollow">http://www.norstad.org/matrix-multiply/index.html</a></p>
  
  <p>I have hadoop setup in pseudodistributed mode and I configured it using this tutorial:</p>
  
  <p><a href="http://hadoop-tutorial.blogspot.com/2010/11/running-hadoop-in-pseudo-distributed.html?showComment=1321528406255#c3661776111033973764" rel="nofollow">http://hadoop-tutorial.blogspot.com/2010/11/running-hadoop-in-pseudo-distributed.html?showComment=1321528406255#c3661776111033973764</a></p>
  
  <p>When I run my jar file then I get the following error:</p>
  
  <pre><code>Identity test
  11/11/30 10:37:34 INFO input.FileInputFormat: Total input paths to process : 2
  11/11/30 10:37:34 INFO mapred.JobClient: Running job: job_201111291041_0010
  11/11/30 10:37:35 INFO mapred.JobClient:  map 0% reduce 0%
  11/11/30 10:37:44 INFO mapred.JobClient:  map 100% reduce 0%
  11/11/30 10:37:56 INFO mapred.JobClient:  map 100% reduce 100%
  11/11/30 10:37:58 INFO mapred.JobClient: Job complete: job_201111291041_0010
  11/11/30 10:37:58 INFO mapred.JobClient: Counters: 17
  11/11/30 10:37:58 INFO mapred.JobClient:   Job Counters
  11/11/30 10:37:58 INFO mapred.JobClient:     Launched reduce tasks=1
  11/11/30 10:37:58 INFO mapred.JobClient:     Launched map tasks=2
  11/11/30 10:37:58 INFO mapred.JobClient:     Data-local map tasks=2
  11/11/30 10:37:58 INFO mapred.JobClient:   FileSystemCounters
  11/11/30 10:37:58 INFO mapred.JobClient:     FILE_BYTES_READ=114
  11/11/30 10:37:58 INFO mapred.JobClient:     HDFS_BYTES_READ=248
  11/11/30 10:37:58 INFO mapred.JobClient:     FILE_BYTES_WRITTEN=298
  11/11/30 10:37:58 INFO mapred.JobClient:     HDFS_BYTES_WRITTEN=124
  11/11/30 10:37:58 INFO mapred.JobClient:   Map-Reduce Framework
  11/11/30 10:37:58 INFO mapred.JobClient:     Reduce input groups=2
  11/11/30 10:37:58 INFO mapred.JobClient:     Combine output records=0
  11/11/30 10:37:58 INFO mapred.JobClient:     Map input records=4
  11/11/30 10:37:58 INFO mapred.JobClient:     Reduce shuffle bytes=60
  11/11/30 10:37:58 INFO mapred.JobClient:     Reduce output records=2
  11/11/30 10:37:58 INFO mapred.JobClient:     Spilled Records=8
  11/11/30 10:37:58 INFO mapred.JobClient:     Map output bytes=100
  11/11/30 10:37:58 INFO mapred.JobClient:     Combine input records=0
  11/11/30 10:37:58 INFO mapred.JobClient:     Map output records=4
  11/11/30 10:37:58 INFO mapred.JobClient:     Reduce input records=4
  11/11/30 10:37:58 INFO input.FileInputFormat: Total input paths to process : 1
  11/11/30 10:37:59 INFO mapred.JobClient: Running job: job_201111291041_0011
  11/11/30 10:38:00 INFO mapred.JobClient:  map 0% reduce 0%
  11/11/30 10:38:09 INFO mapred.JobClient:  map 100% reduce 0%
  11/11/30 10:38:21 INFO mapred.JobClient:  map 100% reduce 100%
  11/11/30 10:38:23 INFO mapred.JobClient: Job complete: job_201111291041_0011
  11/11/30 10:38:23 INFO mapred.JobClient: Counters: 17
  11/11/30 10:38:23 INFO mapred.JobClient:   Job Counters
  11/11/30 10:38:23 INFO mapred.JobClient:     Launched reduce tasks=1
  11/11/30 10:38:23 INFO mapred.JobClient:     Launched map tasks=1
  11/11/30 10:38:23 INFO mapred.JobClient:     Data-local map tasks=1
  11/11/30 10:38:23 INFO mapred.JobClient:   FileSystemCounters
  11/11/30 10:38:23 INFO mapred.JobClient:     FILE_BYTES_READ=34
  11/11/30 10:38:23 INFO mapred.JobClient:     HDFS_BYTES_READ=124
  11/11/30 10:38:23 INFO mapred.JobClient:     FILE_BYTES_WRITTEN=100
  11/11/30 10:38:23 INFO mapred.JobClient:     HDFS_BYTES_WRITTEN=124
  11/11/30 10:38:23 INFO mapred.JobClient:   Map-Reduce Framework
  11/11/30 10:38:23 INFO mapred.JobClient:     Reduce input groups=2
  11/11/30 10:38:23 INFO mapred.JobClient:     Combine output records=2
  11/11/30 10:38:23 INFO mapred.JobClient:     Map input records=2
  11/11/30 10:38:23 INFO mapred.JobClient:     Reduce shuffle bytes=0
  11/11/30 10:38:23 INFO mapred.JobClient:     Reduce output records=2
  11/11/30 10:38:23 INFO mapred.JobClient:     Spilled Records=4
  11/11/30 10:38:23 INFO mapred.JobClient:     Map output bytes=24
  11/11/30 10:38:23 INFO mapred.JobClient:     Combine input records=2
  11/11/30 10:38:23 INFO mapred.JobClient:     Map output records=2
  11/11/30 10:38:23 INFO mapred.JobClient:     Reduce input records=2
  Exception in thread "main" java.io.IOException: Cannot open filename /tmp/Matrix Multiply/out/_logs
          at org.apache.hadoop.hdfs.DFSClient$DFSInputStream.openInfo(DFSClient.ja va:1497)
          at org.apache.hadoop.hdfs.DFSClient$DFSInputStream.&lt;init&gt;(DFSClient.java :1488)
          at org.apache.hadoop.hdfs.DFSClient.open(DFSClient.java:376)
          at org.apache.hadoop.hdfs.DistributedFileSystem.open(DistributedFileSyst em.java:178)
          at org.apache.hadoop.io.SequenceFile$Reader.openFile(SequenceFile.java:1 437)
          at org.apache.hadoop.io.SequenceFile$Reader.&lt;init&gt;(SequenceFile.java:142 4)
          at org.apache.hadoop.io.SequenceFile$Reader.&lt;init&gt;(SequenceFile.java:141 7)
          at org.apache.hadoop.io.SequenceFile$Reader.&lt;init&gt;(SequenceFile.java:141 2)
          at TestMatrixMultiply.fillMatrix(TestMatrixMultiply.java:62)
          at TestMatrixMultiply.readMatrix(TestMatrixMultiply.java:84)
          at TestMatrixMultiply.checkAnswer(TestMatrixMultiply.java:108)
          at TestMatrixMultiply.runOneTest(TestMatrixMultiply.java:144)
          at TestMatrixMultiply.testIdentity(TestMatrixMultiply.java:156)
          at TestMatrixMultiply.main(TestMatrixMultiply.java:258)
          at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
          at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl. java:57)
          at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAcces sorImpl.java:43)
          at java.lang.reflect.Method.invoke(Method.java:601)
          at org.apache.hadoop.util.RunJar.main(RunJar.java:156)
  </code></pre>
  
  <p>Can someone please suggest me that what am I doing wrong?Thanks</p>