On 2010-04-06, Albert van der Horst <alb...@spenarnc.xs4all.nl> wrote: > To a mathematician sum(set) suggest that the order of summation > doesn't matter. (So I wouldn't use sum for concatenating > lists.) Harshly, sum() should be used only for operator + both > associative and commutative. > > Now for floating point numbers the order of summation is > crucial, not commutative (a+b)+c <> a+(b+c). So the obvious > thing for someone versed in numerical computing do is looking > whether sum() gives any guarantees for order and whether there > may be a special sum() for floating point. (This is not very > realistic, because such a person would have skimmed the math > library a long time ago, but anyway.)
I'm convinced by this argument. I just have to be a mathematician and a computer scientist skilled in numerical computing. No problem! Just a *few more years* of education and I'll be ready for summing things in Python. ;) -- Neil Cerutti -- http://mail.python.org/mailman/listinfo/python-list
