# [racket] Questions on Typed Racket's FlVector

On Fri, Apr 6, 2012 at 10:49 AM, Ray Racine <ray.racine at gmail.com> wrote:
>* Morning,
*>*
*>* I'm putting together an equivalent of a dataframe from R in Racket.
*>*
*>* To maximize performance of computation over vectors of real numbers is
*>* FlVector the correct type to use in Typed Racket?
*
Yes, flvectors in general will be more memory effcient and enable more
optimizations in Racket and Typed Racket.
>* Is there some sort of performance gain by having flvector-length in addition
*>* to vector-length?
*
No, that's just how flvectors work -- they have a different function
for getting the length.
>* Is the following behavior a bug?
*>*
*>>* (vector-length (flvector 1.2 2.3))
*>* stdin::43119: Type Checker: Expected Vector, but got FlVector in: (flvector
*>* 1.2
*
No, that operation is a (dynamic) error in Racket as well:
-> (vector-length (flvector))
; vector-length: expects argument of type <vector>; given: #<flvector>
--
sam th
samth at ccs.neu.edu