Couldn't you give EvalFunc<any return type> any return type? so you can just
return a Bag that contains tuples of tuples, right? And it's easy because
tuple is un parameterized type, (and so is Bag) so you'd declare
class myUdf extends EvalFunc<Bag>{...}
I haven't tried this, but some times I'm tempted to return something weird
like
EvalFunc<Chicken>
and see chickens come out of pig. ;-) heheheheeee
Anyways, in all seriousness, there is a UDF that converts data to bag (well,
currently a contrib Udf, but may make into bultin) that I wrote called
ToBag. here's the initial declaration for it:
public class ToBag extends EvalFunc<DataBag>
Your class would be declared similarly.
On Fri, May 28, 2010 at 7:50 AM, Asif Jan <[email protected]> wrote:
> Hello
>
> I need some help to get started with using Pig UDF.
>
> I have time series data (time, magA, errA, magB, errB) e.g.
>
> (2345.59777,19.875,0.481,20.225,0.482)
> (2347.59568,19.371,0.3,20.227,0.743)
> (2351.6075,19.063,0.193,20.768,1.085)
> (2354.59702,20.689,3.047,20.873,1.758)
> (2356.63223,21.23,3.341,20.562,1.242)
>
>
> and I need to apply an algorithm that searches for periods in the data.
> The input to the algorithm is the (time , magX, errX ) arrays. The algo
> returns a List of all periods found. Each entry in the List is a
> (period_value , period_significance) pair.
>
>
> How can I wrap that algo as UDF ? do I have to use algebraic functions
> (but I saw that they could only return scalar values ); what I need to
> return from function is something like
>
> (1000.0,0.57)
> (234, .45)
> (100, 0.023)
> (6, 0.003)
>
>
> thanks a lot
>
>
>
>
>
>
>
