wrapc does look plausible - to avoid memory problems we could break the processing of the problematic line so it chews on smaller chunks of data.
And, I am expecting that one step of iteration have a computational cost which is a multiple of the square of the number of distinct nodes reached so far - I think that that's wired into the specification. Anyways, I need to be doing real work, right now, not having fun, so I'll have to come back to this later. Thanks, -- Raul On Fri, Feb 15, 2013 at 2:55 PM, Mike Day <[email protected]> wrote: > Yes, "tree" is not the best word, though it does hint at the existence of > branches - however its structure doesn't reveal the links. Each row is a > sorted list, I suppose. Whatever we call it, I think you've got a big > problem in finding all such "things" each with 100 unique members, in a > 2000-node graph. At least I don't yet see how to do it given the memory > problems at N=11! > > Better to look at wrapc than wrapb, I suggest. It does nub after sorting > the lists as you suggest. > > I'm about to do the Times Listener Crossword now (a numerical one this > week!) so won't be path hunting for a while. > > Good luck > > Mike > > > On 15/02/2013 7:19 PM, Raul Miller wrote: >> >> Thank you, again. >> >> I have not yet had time to read through wrapb, but a quick glance >> suggests that the "too many paths (or 'trees', maybe )" issue could >> probably be resolved by sorting each "path" before determining >> uniqueness. >> >> That said, I am more uncomfortable labelling these "visitable sets" >> with the word "trees" rather than "paths". A tree would imply, to me, >> that I've retained a particular connection structure, and all I care >> about is whether the node has been visited. Perhaps I should model >> this as "when a connection is used the reverse connection is also made >> available in the context of that path" - actually implementing that >> seems computationally inefficient, but it would resolve the conflict >> between this use of the word "path" and its use in other graph >> problems. >> >> Thanks, >> > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
