On Sun, Jul 25, 2010 at 6:33 PM, Dan Drake <dr...@kaist.edu> wrote: > Hello, > > Ticket #9590 fixes a problem with hashing; it looks like the hash value > in the doctest is 32- or 64-bit specific, and of course it fails on > systems that don't match. The solution there is to change a doctest like > > sage: hash(foo) > 574575757575 > > into > > sage: hash(foo) == hash(foo) > True > > That avoids using the particular value, which we don't really care about > anyway, but I'm not certain this is a good solution, since the new > doctest really only tests that the hash function actually returns a > value. > > I don't know much about the hashing functions, so maybe the new doctest > is fine. There are some other fixes proposed on that ticket; should I > merge the current fix, or should we use 32-bit and 64-bit tags to use > different values?
Hmm... looks like the current state of affairs is a mess. Looking through the 'def __hash__' grep hits in sage/rings, there are quite a few of each of the following: 1) no doctest at all 2) provide both 32-bit and 64-bit doctests 3) define your hash function to produce a 32-bit output that's the same on 32-bit and 64-bit systems; doctest an instance of that output 4) doctest hash value equality without ever showing a doctest output plus one instance where the hash output is marked "# random". So whatever you do with this particular patch, it won't make things much worse :) As for the desired state of affairs: I have a slight preference for providing both 32-bit and 64-bit doctest outputs, because it increases our chance of noticing if something changes unexpectedly. But I could also make a good case for only testing hash equality, because it slightly reduces the effort involved in changing hash functions, internal representations, etc. :) Carl -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
