Hello, On Saturday, March 15, 2014 11:37:11 PM UTC+1, Jules wrote: > > 2. I've had a look at rrb-vector - very fast for catvec - agreed, but > there does appear to be a performance penalty in terms of conj[!]-ing - I > can post my results if you are interested. I read the Bagwell paper on > which your work was based and came away with the impression that he did not > think he was introducing significant overhead with his improvements for > constant tiime concatenation - so maybe this is due to rrb being impled in > clojure and builting vec in java ? >
I've not looked at the implementation done by Michał in detail (lack of documentation makes it a tad hard to grok), but a properly implemented variant should have about the same performance as a normal vector when no concatenation has been done on the vector, and would only require one extra check. Transients which aren't concatenated should have same performance guarantees as transient Clojure vectors, but only if the node size is fixed to 32 elements. However, I've found it rather hard to perform the general conj-case efficiently, so you're right that conjing will be slower on average in an RRB-vector after concatenations. I'm trying to find ways to cut off large parts of the constant factor off, and hope to get some results dished out in some months time. Another factor here is that the Clojure impl *may* suffer from suboptimal JVM-emitted code, although that is purely speculation from my side. As for 3, I've not looked into GPU programming of these things as the memory is not contiguous and would probably be messy to transfer over. -- JN -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to [email protected] Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
