-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Anne Archibald wrote: > > It would be perfectly possible, in principle, to implement an > ATLAS-like library that handled a variety (perhaps all) of numpy's > basic operations in platform-optimized fashion. But implementing ATLAS > is not a simple process! And it's not clear how much gain would be > available - it would almost certainly be noticeably faster only for > very large numpy objects (where the python overhead is unimportant), > and those objects can be very inefficient because of excessive > copying. And the scope of improvement would be very limited; an > expression like A*B+C*D would be much more efficient, probably, if the > whole expression were evaluated at once for each element (due to > memory locality and temporary allocation). But it is impossible for > numpy, sitting inside python as it does, to do that.
numexpr (in the scipy sandbox) does something like this: it takes an expression like A*B+C*D and constructs a small bytecode program that does that calculation in chunks, minimising temporary variables and number of passes through memory. As it is, the speed is faster than the python expression, and comparable to that of weave. I've been thinking of making a JIT for it, but I haven't had the time :) - -- |>|\/|< /------------------------------------------------------------------\ |David M. Cooke http://arbutus.physics.mcmaster.ca/dmc/ |[EMAIL PROTECTED] -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.7 (Darwin) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFGJbvTN9ixZKFWjRQRAi+WAJ9HmeCTeB59Jso5vlVzbgHQ0TDj9ACfdKWy jYEnsRYau8T5BVAKnZJWpLk= =75Jc -----END PGP SIGNATURE----- _______________________________________________ Numpy-discussion mailing list Numpy-discussion@scipy.org http://projects.scipy.org/mailman/listinfo/numpy-discussion
