On Thu, Oct 29, 2009 at 4:49 AM, Konrad Hinsen <konrad.hin...@fastmail.net>wrote:
> On 28 Oct 2009, at 22:21, Rock wrote: > > I honestly prefer your first case scenario. Seems much more efficient, > > less resource-consuming, and just straightforward. But I really would > > like to know what your preference is. If you had to choose, which way > > would you go? > > If I were to design an array interface for Clojure, it would consist > of multimethods implemented for both an efficient array data structure > for internal use and for nested vectors. The implementation for the > latter would convert the nested vectors to the efficient structure and > do all the necessary checks. It would be there for convenience and > clarity in user code. Ideally I would then implement the same > interface for Colt arrays and netCDF arrays as well, both for having > an effcient structure for large data sets and for interoperability. > And once we are at it, why not have another implementation for sparse > arrays, using a suitable data structure? One issue with using multimethods is the resolution overhead. I don't think the JIT can optimize this to the extent it can optimize a normal polymorphic Java call. So you might want to use a Java interface for this instead, and Clojure's Java interop with macros to wrap a nice Clojury API around it. A second problem is boxing of primitives, and a third is noncontiguous storage. The Java for the nonsparse stuff should probably use and expose Java arrays of primitives. If you can live without runtime polymorphism, having only compile-time polymorphism, the polymorphism can move back to the Clojure side but live in a macro; then a sugar-coated API call directly translates at macroexpand time into manipulation of Java arrays in either Java calls or a Clojure function that uses loop/recur with primitives and is loaded with type hints for the array type used (likely double[]). --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en -~----------~----~----~----~------~----~------~--~---
