What I am trying to say is, tolerant comparison is just a way to see if two numbers are probably actually the same number, but represented slightly differently because of rounding error.
A comparison that would say, for example, that 1 = 2, is so far removed from a comparison intended to mask the effects of rounding that, even though the mathematical description might be similar, the implementation is different. Such a wide 'tolerance', which I called interval comparison, is an application-specific requirement that is not, and should not be, part of the general-purpose language. Henry Rich > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Oleg Kobchenko > Sent: Monday, May 29, 2006 11:27 PM > To: Programming forum > Subject: RE: [Jprogramming] Equal tolerance fit conjunction -- again > > You are talking about tolerance and comparison > on intervals as if they were two diffent things. > What is your definition of comparison on intervals? > > > --- Henry Rich <[EMAIL PROTECTED]> wrote: > > > > However, for some mystical reasons J implementation > > > does not allow the tolerance (factor of the radius) > > > to grow above 2^_34, thus, as pointed out by Roger Hui > > > http://www.jsoftware.com/jwiki/Essays/Tolerant_Comparison > > > ... This is also why it's hard to grasp > > > this limitation concept. > > > > It is my understanding that tolerant comparison is intended > > not to solve any application problem, but just to hide the > > numerical inaccuracies that result from floating-point > > arithmetic. For such a use, relative tolerance is > > the right approach, and 2^_34 is plenty big. > > > > If your application needs comparison on intervals, you > > are expected to code it yourself. Tolerance larger than > > 2^_34 hurts integer code & so is not available as a way > > to handle interval comparisons. > > > > Henry Rich > > > __________________________________________________ > Do You Yahoo!? > Tired of spam? Yahoo! Mail has the best spam protection around > http://mail.yahoo.com > ---------------------------------------------------------------------- > For information about J forums see > http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
