org.apache.pig.piggybank.evaluation.math

Class DoubleSignum

java.lang.Object

org.apache.pig.EvalFunc<java.lang.Double>

org.apache.pig.piggybank.evaluation.math.DoubleSignum

public class DoubleSignum
extends EvalFunc<java.lang.Double>

math.SIGNUM implements a binding to the Java function Math.signum(double). Given a single data atom it Returns the signum function of the argument.

Parameters:

value - Double.

Return Value:

Double

Return Schema:

SIGNUM_inputSchema

Example:

register math.jar;
A = load 'mydata' using PigStorage() as ( float1 );
B = foreach A generate float1, math.SIGNUM(float1);

Author:

ajay garg

See Also:

Math.signum(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

Constructors

Constructor and Description
DoubleSignum()

Method Summary

Modifier and Type	Method and Description
java.lang.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

allowCompileTimeCalculation, finish, getArgToFuncMapping, getCacheFiles, getInputSchema, getLoadCaster, getLogger, getPigLogger, getReporter, getReturnType, getSchemaName, getSchemaType, getShipFiles, isAsynchronous, needEndOfAllInputProcessing, progress, setEndOfAllInput, 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

DoubleSignum

public DoubleSignum()

Method Detail

exec

public java.lang.Double exec(Tuple input)
                      throws java.io.IOException

java level API

Specified by:

exec in class EvalFunc<java.lang.Double>

Parameters:

input - expects a single numeric DataAtom value

output - returns a single numeric DataAtom value, signum function of the argument

Returns:

result, of type T.

Throws:

java.io.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<java.lang.Double>

Parameters:

input - Schema of the input

Returns:

Schema of the output