Alistair Tucker wrote:
>     I have read that Core2's specialised vector processor (SSE)
> runs at fully twice the speed of the Core's.  Presumably that
> means that an array-centric application like J will run twice
> as fast?

Unlikely.

SSE's optimizations work around bandwidth limitations in the CPU
(such as would hit you in the context of large arrays) in a
fashion which is most useful when dealing with small fix-sized
arrays.

SSE would probably be useful in the context of some of J's
"special code" -- special case algorithms which take advantage
of the restrictions implied by certain sequences of operations.
But I doubt very much that SSE would be much use for J's core
operations.

On top of that, SSE does not work on all PCs.  This means that
if SSE were used, we'd either see a different executable which
supports SSE, or J would be larger (as it would need to incorporate
an additional non-SSE implementation of every routine which
supports SSE).

Finally, if the ISI folks had gone to the effort of providing
"special SSE" code, I think it would be documented in the
release notes.

-- 
Raul


----------------------------------------------------------------------
For information about J forums see http://www.jsoftware.com/forums.htm

Reply via email to