org.apache.pig.piggybank.evaluation.math
Class DoubleUlp

java.lang.Object
  extended by org.apache.pig.EvalFunc<Double>
      extended by org.apache.pig.piggybank.evaluation.math.DoubleUlp

public class DoubleUlp
extends EvalFunc<Double>

math.ULP implements a binding to the Java function Math.ulp(double). Given a single data atom it Returns the size of an ulp of the argument.

Parameters:
value - Double.
Return Value:
Double
Return Schema:
ULP_inputSchema
Example:
register math.jar;
A = load 'mydata' using PigStorage() as ( float1 );
B = foreach A generate float1, math.ULP(float1);

Author:
ajay garg
See Also:
Math.ulp(double),

Nested Class Summary
 
Nested classes/interfaces inherited from class org.apache.pig.EvalFunc
EvalFunc.SchemaType
 
Field Summary
 
Fields inherited from class org.apache.pig.EvalFunc
log, pigLogger, reporter, returnType
 
Constructor Summary
DoubleUlp()
           
 
Method Summary
 Double exec(Tuple input)
          java level API
 Schema outputSchema(Schema input)
          Report the schema of the output of this UDF.
 
Methods inherited from class org.apache.pig.EvalFunc
finish, getArgToFuncMapping, getCacheFiles, getInputSchema, getLogger, getPigLogger, getReporter, getReturnType, getSchemaName, getSchemaType, 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

DoubleUlp

public DoubleUlp()
Method Detail

exec

public Double exec(Tuple input)
            throws IOException
java level API

Specified by:
exec in class EvalFunc<Double>
Parameters:
input - expects a single numeric value
output - returns a single numeric value, the size of an ulp of the argument.
Returns:
result, of type T.
Throws:
IOException

outputSchema

public Schema outputSchema(Schema input)
Description copied from class: EvalFunc
Report the schema of the output of this UDF. Pig will make use of this in error checking, optimization, and planning. The schema of input data to this UDF is provided.

The default implementation interprets the OutputSchema annotation, if one is present. Otherwise, it returns null (no known output schema).

Overrides:
outputSchema in class EvalFunc<Double>
Parameters:
input - Schema of the input
Returns:
Schema of the output


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