On Sep 1, 5:27 pm, Sebastian Pancratz <s...@pancratz.org> wrote:
> I don't think this change in code should be used as a band-aid to make > things work in one of the trac tickets you mentioned earlier. For the problem that raised all the stuff up I have an alternative solution (with pros and cons of course) > On to the next points... your examples do show that lcm isn't as well > set up as gcd with respect to the coercion system. If you're > implementing gcd/ lcm for field elements already, could you change > this, too? (I unfortunately can't claim to understand the coercion > system well enough to "just do this quickly".) Yes, that should be corrected, I am looking at this. > There seems to be another problem suggested by your examples. Of > course, if a user does > > sage: x.gcd(y) > > then I would think the user wants y to be interpreted as an element of > the parent of x, if possible. That is, the operation x.gcd(y) is > *not* necessarily symmetric. On the other hand, if a user types > > sage: gcd(x, y) > > one might (mistakenly) expect it to be symmetric. Of course, in > principle this problems might have come up with many other operations > which a mathematician would expect to be commutative. Perhaps a > solution to this way has been discussed somewhere else already? > Otherwise, looking at the implementation of addition should give some > guidelines. This is considered in the sage.structure.element.pyx through coerce_bin_op I will carefully read the module. -- 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
