datafu.pig.stats
Class MarkovPairs

java.lang.Object
  org.apache.pig.EvalFunc<org.apache.pig.data.DataBag>
      datafu.pig.stats.MarkovPairs

public class MarkovPairs
extends org.apache.pig.EvalFunc<org.apache.pig.data.DataBag>

Accepts a bag of tuples, with user supplied ordering, and generates pairs that can be used for a Markov chain analysis. For example, if you had {(1), (4), (7)}, using the default lookahead of 1, you get the pairs { ((1),(4)), ((4),(7))} A lookahead factor tells the UDF how many steps in to the future to include. so, for a,b,c with a lookahead of 2, a would be paired with both b and c. The results are ordered are returned as ordered by the caller.

Field Summary

Fields inherited from class org.apache.pig.EvalFunc

log, pigLogger, reporter, returnType

Constructor Summary

MarkovPairs()

MarkovPairs(java.lang.String lookahead_steps)

Method Summary

org.apache.pig.data.DataBag	exec(org.apache.pig.data.Tuple input)
org.apache.pig.impl.logicalLayer.schema.Schema	outputSchema(org.apache.pig.impl.logicalLayer.schema.Schema input)

Methods inherited from class org.apache.pig.EvalFunc

finish, getArgToFuncMapping, getCacheFiles, getInputSchema, getLogger, getPigLogger, getReporter, getReturnType, getSchemaName, isAsynchronous, progress, setInputSchema, setPigLogger, setReporter, setUDFContextSignature, warn

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

MarkovPairs

public MarkovPairs()

MarkovPairs

public MarkovPairs(java.lang.String lookahead_steps)

Method Detail

exec

public org.apache.pig.data.DataBag exec(org.apache.pig.data.Tuple input)
                                 throws java.io.IOException

Specified by:

exec in class org.apache.pig.EvalFunc<org.apache.pig.data.DataBag>

Throws:

java.io.IOException

outputSchema

public org.apache.pig.impl.logicalLayer.schema.Schema outputSchema(org.apache.pig.impl.logicalLayer.schema.Schema input)

Overrides:

outputSchema in class org.apache.pig.EvalFunc<org.apache.pig.data.DataBag>