On Fri, 2009-12-04 at 10:50 -0600, Sebastian Pop wrote: > On Fri, Dec 4, 2009 at 10:39, Tobias Grosser <gros...@fim.uni-passau.de> > wrote: > > I do not believe this is already possible for arbitrary N. > > > > You would have to write a scattering function like this > > > > s0 = i+n*(j-1) > > > > What is > > > > s= i + n*j - n > > ^^^ Here is a product that is not affine linear. > > Yes this is affine linear, but not representable in the current way we > deal with parameters in the polyhedral model... Note that constant > times IV would be allowed, and yes parameters are named constants.
However at the moment we represent parameters as variables that tend to be constant. So as you said that will not work. Probably there is some way to regenerate the loops from scratch based on analysing the memory dependencies, as in this case such a complicated scattering is probably not required. But this case is definitely not that easy to solve. > > There are extensions to the polytop model to make this possible, but > > they are not close to be production ready. > > I think that we should revisit this independently of general solutions. > > > Just recently I Armin Groesslinger gave a nice talk about this > > topic. If you want I can look for his work describing solutions. > > I also have discussed with Armin when I was visiting INRIA earlier > this year, and I know what he's working on. > > Sebastian
