On Thu, Sep 02, 2010 at 01:11:07AM +0200, Dr.Ruud wrote: > On 2010-09-02 00:49, Paul Johnson wrote: > >> When you want to compare floating point numbers, check that their >> difference is less than some appropriately small delta: >> >> $delta = 1e-8; >> >> if (abs($a - $b)< $delta) # numbers are "equal" > > Why call it delta when you can call it epsilon? > ;)
You're absolutely right. And see Test::Number::Delta on CPAN for an easier way of doing this in tests. > It also has no 'my', why is that? Because it is a short snippet of code designed to show one principle. Adding "my" would not have contributed to that goal. I was also expecting someone to pick me up on using $a and $b. Perhaps they still will. The answer would be very similar. > And OP should read at least one of these: > http://docs.sun.com/source/806-3568/ncg_goldberg.html > http://en.wikipedia.org/wiki/Floating_point > http://hal.archives-ouvertes.fr/docs/00/28/14/29/PDF/floating-point-article.pdf Yes, this is a well understood problem that nevertheless manages to perplex many beginning programmers. -- Paul Johnson - p...@pjcj.net http://www.pjcj.net -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
