On Fri, Apr 8, 2011 at 7:42 PM, Gennadiy Rozental <rogeeff@gmail.com> wrote:
Jeffrey Lee Hellrung, Jr. <jeffrey.hellrung <at> gmail.com> writes:
My point was to nudge you toward percent or fraction based tolerance. I believe the OP had already explained why relative tolerances were incorrect for his/her application.
I don't think so. He claimed he want absolute difference comparison without explaining why and relative is not applicable.
Okay, there probably weren't enough details for a thorough justification, so my claim was indeed incorrect. I meant to say something along the lines of: I took the OP at his/her word that he/she had determined that absolute tolerances were correct to use and relative tolerances were incorrect. My point is that *usually* one should prefer later.
Perhaps, but that makes an implicit assumption about the "usual" application. In any case, usual or not, do we accept that absolute tolerances are sometimes preferable to relative tolerances? I would. If so, does it occur frequently enough to warrant the macro(s) (or a similar one(s)) that the OP suggested, similar to existing macros that check equality within relative tolerances? I don't know. But the only drawback I see with including such macros is a perhaps misplaced encouragement from the point of view of users to use the macros which determine equality within absolute tolerances; do we not trust users enough to determine on their own which tolerance type is appropriate for their application? - Jeff