4 Jan
2010
4 Jan
'10
8:43 p.m.
Am Montag 04 Januar 2010 22:25:28 schrieb Daniel Fischer:
compos ps = fst (tfold mergeSP $ nwise 1 mergeSP (pairwise mergeSP (multip ps)))
tfold f (a: ~(b: ~(c:xs))) = (a `f` (b `f` c)) `f` tfold f xs
nwise k f xs = let (ys,zs) = splitAt k xs in rfold f ys : nwise (k+1) f zs
rfold f [x] = x rfold f (x:xs) = x `f` rfold f xs
memory still grows, but much slower, in my tests, due to the much smaller GC time, it's a bit faster than the version with the original tfold.
Not for larger inputs (but not so large that the tree-fold dies OOM). Fix rfold: rfold f [x] = x rfold f xs = rfold f (pairwise f xs) and it's faster also for those.