Stefan Behnel wrote: > Tuples support '+' and '*'. My immediate intuition is that an array type > should behave exactly like a (mutable, but fixed-size) tuple, except where > C dictates otherwise. > > >> I'm convinced that + would be used *a lot* more for componentwise >> addition than for concatenation. >> > > I agree - at least in numerics. But if you want a mathematical vector type, > that's a different thing than a memory managed C array IMHO. > > BTW, didn't we have this discussion twice already? That shows that at least > my intuition keeps clearly dictating otherwise, each time we get here. > Hmm, don't remember previous discussions. Anyway there's not that much to *discuss* as such; there's obvious interests at conflict here and the case seems clear for both.
I'll try to put down the interesting points: 1) Concatenation is a slow operation with large overhead where one can after all just use Python objects or cdef methods with negligble overhead. Addition is a real usecase where Cython can provide something Python/NumPy can not provide (by reducing memory bus traffic for large expressions). I.e. concatenation can be done without this feature, while for efficient expression evaluation one would have to switch to another language -- there's NO way of getting it in Cython otherwise. 2) I'd have to reconsider how much work I'm willing to put into this given concatenation semantics. I am scratching my own itch here. If + is chosen for concatenation I might end up having to use Fortran anyway in some cases (where Python/NumPy isn't fast enough), and so my motivation would be mainly on getting Kurt's GSoC through rather than empower Cython in general in this area. 3) Sometimes no feature at all is much better than a wrong or unintuitive feature, so 2) should NOT decide this, and I'll deal just fine with a "no" nevertheless :-) 4) Looking at mailing list activity, the numerical crowd is a very significant user of Cython 5) But again, the numerical stuff has happened as a byproduct, I realize that neither you nor Robert need it, and that Cython's real goal lies elsewhere Trying one last time for constructive solutions though: - There's always compiler directives - Or int[:,:,componentwise=True] OTOH, clearly rsq = add(mul(x, x), mul(y, y)) is rather out of the question :-) Dag Sverre _______________________________________________ Cython-dev mailing list Cython-dev@codespeak.net http://codespeak.net/mailman/listinfo/cython-dev
