[Haskell-cafe] Re: Mining Twitter data in Haskell and Clojure

Claus Reinke claus.reinke at talk21.com
Thu Jun 17 14:36:13 EDT 2010

> I'll work with Simon to investigate the runtime, but would welcome any
> ideas on further speeding up cafe4.

Just a wild guess, but those foldWithKeys make me nervous.

The result is strict, the step function tries to be strict, but if
you look at the code for Data.IntMap.foldr, it doesn't really
give you a handle for propagating that strictness. Unless
the foldr definition is inlined into your code, the generic,
non-strictly accumulating version might be called. Have
you checked that this isn't the case?

Also, shouldn't the two foldWithKeys on dm be merged?
And, while Maps are strict in their representation, putting 
them into a non-strict field of a data structure might lose 

As I said, just guessing;-)


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