<div dir="ltr">I just grabbed two separate witnesses showing the result of the relevant floating point math - I apologize for any offense. <div class="gmail_quote">On Tue Feb 24 2015 at 1:15:01 PM Matthias Felleisen <<a href="mailto:matthias@ccs.neu.edu">matthias@ccs.neu.edu</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> That's the saddest argument in support of anything Racket I have ever seen (even with the smiley). On Feb 24, 2015, at 1:05 PM, Andrew Kent <<a href="mailto:andmkent@indiana.edu" target="_blank">andmkent@indiana.edu</a>> wrote: > Racket: > (+ .1 .1 .1 .1 .1 .1 .1 .1) > 0.7999999999999999 > > Python: > >>> .1 + .1 + .1 + .1 + .1 + .1 + .1 + .1 > > 0.7999999999999999 > > Looks consistent to me =) > > > On Tue Feb 24 2015 at 10:43:19 AM Laurent <<a href="mailto:laurent.orseau@gmail.com" target="_blank">laurent.orseau@gmail.com</a>> wrote: > I've discovered a rather troubling behaviour when using `in-range` with floating point numbers, which I think is worth knowing in case you hadn't consider the issue before: > > On my machine, I get the following: > > (length (for/list ([i (in-range .1 .7 .1)]) i)) ; 6 > (length (for/list ([i (in-range .1 .8 .1)]) i)) ; 8 (!) > > But: > (length (for/list ([i (in-range 1/10 7/10 1/10)]) i)) ; 6 > (length (for/list ([i (in-range 1/10 8/10 1/10)]) i)) ; 7 > > > Would it be a good idea to safe-guard these kinds of cases directly in `in-range`? > > > > > > > > ____________________ > Racket Users list: > <a href="http://lists.racket-lang.org/users" target="_blank">http://lists.racket-lang.org/users</a> > ____________________ > Racket Users list: > <a href="http://lists.racket-lang.org/users" target="_blank">http://lists.racket-lang.org/users</a> </blockquote></div></div>