Question

我正在尝试计算维基百科文档之间的行相似度。我有格式为Key class: class org.apache.hadoop.io.Text Value Class: class org.apache.mahout.math.VectorWritable的tf-idf向量。我正在从这里开始快速浏览文本分析：https://cwiki.apache.org/confluence/display/MAHOUT/Quick+tour+of+text+analysis+using+the+Mahout+command+line

我创建了一个mahout矩阵，如下所示：

mahout rowid \
   -i wikipedia-vectors/tfidf-vectors/part-r-00000
   -o wikipedia-matrix

我得到了生成的行数和列数：

vectors.RowIdJob: Wrote out matrix with 4587604 rows and 14121544 columns to wikipedia-matrix/matrix

矩阵的格式为Key class: class org.apache.hadoop.io.IntWritable Value Class: class org.apache.mahout.math.VectorWritable

我还有一个docIndex文档，格式如下：Key class: class org.apache.hadoop.io.IntWritable Value Class: class org.apache.hadoop.io.Text

然后当我运行行相似性作业

时

mahout rowsimilarity 
   -i wikipedia-matrix/matrix 
   -o wikipedia-similarity 
   -r 4587604
   --similarityClassname SIMILARITY_COSINE
   -m 50
   -ess

我收到以下错误：

13/08/25 15:18:18 INFO mapred.JobClient: Task Id : attempt_201308161435_0364_m_000001_1, Status : FAILED
java.lang.ClassCastException: org.apache.hadoop.io.Text cannot be cast to org.apache.mahout.math.VectorWritable
    at org.apache.mahout.math.hadoop.similarity.cooccurrence.RowSimilarityJob$VectorNormMapper.map(RowSimilarityJob.java:183)
    at org.apache.hadoop.mapreduce.Mapper.run(Mapper.java:144)
    at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:648)
    at org.apache.hadoop.mapred.MapTask.run(MapTask.java:322)
    at org.apache.hadoop.mapred.Child$4.run(Child.java:266)
    at java.security.AccessController.doPrivileged(Native Method)
    at javax.security.auth.Subject.doAs(Subject.java:396)
    at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1278)
    at org.apache.hadoop.mapred.Child.main(Child.java:260)

有人可以帮我解决这个错误吗？当输入矩阵格式为org.apache.hadoop.io.Text

时，我不确定此Key class: class org.apache.hadoop.io.IntWritable Value Class: class org.apache.mahout.math.VectorWritable的位置

非常感谢。

最佳，德拉甘

Answer 1

我使用以下命令解决了它：

hadoop jar mahout-examples-0.9-SNAPSHOT.jar 
org.apache.mahout.math.hadoop.similarity.cooccurrence.RowSimilarityJob 
-i /user/dmilchev/wikipedia-matrix/matrix 
-o /user/dmilchev/wikipedia-similarity 
-r 4587604 --similarityClassname SIMILARITY_COSINE -m 50 -ess

我没有收到任何错误。

Mahout rowSimilarity

1 个答案: