Hi all, I wrote some code for product rings a while back, and went back to it for more computations. My computations took vastly longer, and it seems the culprit is the inverse function in my ring.
The product code ring is here: http://pastebin.com/V2Cx6gVB I ran the following test code: ===== from sage.matroids.advanced import * load /path/to/product_ring.py H5 = ProductRing((GF(5), GF(5), GF(5), GF(5), GF(5), GF(5))) print H5 H5CrossRatios = set([H5(1)]) H5CrossRatios.update([H5(x) for x in Permutations([2, 2, 3, 3, 4, 4])]) L = list(H5CrossRatios) print len(H5CrossRatios) timeit(""" s = 0 for i in xrange(91): for j in xrange(91): for k in xrange(30): s = s + L[i] + (L[j])^(-1) * L[k]""", number=1, repeat=1) ===== In Sage 5.12 this takes 6.41 seconds on my computer; in Sage 6.5.beta5 it takes 117 seconds. The culprit is the inverse, if you do just addition and multiplication the code runs in the same amount of time. So... * did I implement my ring wrong, and did it just happen to work better in the past? * can I change my ring code to speed this back up? * can you point to a change in Sage that could have caused this? And help me think about a way to fix it? Cheers, Stefan -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
