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Instant MapReduce Patterns – Hadoop Essentials How-to by Srinath Perera

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Cross correlation with MapReduce (Intermediate)

Cross correlation detects the number of times two things occur together. For example, in the Amazon dataset, if two buyers have bought the same item, we say that they are cross correlated. Through cross correlation, we count the number of times two customers have bought a same item.

Getting ready

  1. This assumes that you have installed Hadoop and started it. Writing a word count application using Java (Simple) and Installing Hadoop in a distributed setup and running a word count application (Simple) recipes for more information. We will use the HADOOP_HOME to refer to the Hadoop installation directory.
  2. This recipe assumes you are aware of how Hadoop processing works. If you have not already done so, ...

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