[Haskell-cafe] vector-space and standard API for vectors
schlepptop at henning-thielemann.de
Sat Oct 30 06:07:28 EDT 2010
wren ng thornton schrieb:
> On 10/22/10 8:46 AM, Alexey Khudyakov wrote:
>> Hello everyone!
>> It's well known that Num & Co type classes are not adequate for vectors
>> (I don't mean arrays). I have an idea how to address this problem.
>> Conal Elliott wrote very nice set of type classes for vectors.
>> (Definition below). I used them for some time and quite pleased. Code is
>> concise and readable.
>> > class AdditiveGroup v where
>> > zeroV :: v
>> > (^+^) :: v -> v -> v
>> > negateV :: v -> v
>> I'd like to know opinion of haskellers on this and specifically opinion
>> of Conal Eliott as author and maintainer (I CC'ed him)
Looks like you are about to re-implement numeric-prelude. :-)
> Just my standard complaint: lack of support for semirings, modules, and
> other simple/general structures. How come everyone's in such a hurry to
> run off towards Euclidean spaces et al.?
> I'd rather see,
> class Additive v where -- or AdditiveMonoid, if preferred
> zeroV :: v
> (^+^) :: v -> v -> v
> class Additive v => AdditiveGroup v where
> negateV :: v -> v
> type family Scalar :: * -> *
Vector (Complex a) is a vector with respect to both 'a' and 'Complex a'.
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