Hey, when you're old enough to have programmed with Fortran IV, you have heard a lot of things. There's an even name I picked up at Rice, but I can't recall.
Thanks for adding these things to the math library. On Jul 29, 2012, at 7:31 PM, Neil Toronto wrote: > On 07/29/2012 04:19 PM, Danny Yoo wrote: >> On Sun, Jul 29, 2012 at 6:07 PM, Matthias Felleisen >> <matth...@ccs.neu.edu> wrote: >>> >>> For 81 slots, I'd actually use a (define b (make-vector 81 0)) instead and >>> use an access polynomial. I am almost certain that it is faster. > > Probably so. It allocates less and has better cache behavior when accessing > elements in row-major order. > >> I'm unfamiliar with the term 'access polynomial'. Would it be >> accurate to say that it's a function f: >> >> f: (number number -> number) >> >> such as >> >> (define COLUMN-LENGTH 9) >> (define (f row col) (+ (* row COLUMN-LENGTH) col)) >> >> allows us to treat the flat vector as if it were a two-dimensional >> structure, by translating (row,col) into offsets? > > That's it. I've never heard it called an "access polynomial" before, though > that's exactly what it is. > > When I merge the `math' collection for 5.4, such decisions will mostly be > moot. It has an Array type, which does that for you in any number of > dimensions. > > Neil ⊥ > > ____________________ > Racket Users list: > http://lists.racket-lang.org/users ____________________ Racket Users list: http://lists.racket-lang.org/users
