Oscar Gustafsson wrote: > I would take it that round x to N radix-R digits means > round_to_integer(x * R**N)/R**N > (ignoring floating-point issues)
Yes, this is the tried-and-true way: first define the function in exact arithmetic, then ask for the floating point implementation to return an approximate result within a given tolerance, say 1/2 ulp. This is what CPython does, and it seems to be quite hard to get it right, at least inspecting the code of the current implementation. BTW I think that numpy uses the same definitions, but simply accepts a bigger (not specified) tolerance in its implementation. Maybe I should have phrased my question differently: is this definition the only accepted one, or there are different formulations which give raise to more expedite implementations? _______________________________________________ NumPy-Discussion mailing list -- numpy-discussion@python.org To unsubscribe send an email to numpy-discussion-le...@python.org https://mail.python.org/mailman3/lists/numpy-discussion.python.org/ Member address: arch...@mail-archive.com
