# Re: Possreps and numeric types

From: Bob Badour <bbadour_at_pei.sympatico.ca>

Date: Thu, 29 Mar 2007 17:44:30 GMT

Message-ID: <2WSOh.16999$PV3.175012_at_ursa-nb00s0.nbnet.nb.ca>

>>Gene Wirchenko wrote:

Date: Thu, 29 Mar 2007 17:44:30 GMT

Message-ID: <2WSOh.16999$PV3.175012_at_ursa-nb00s0.nbnet.nb.ca>

> Bob Badour <bbadour_at_pei.sympatico.ca> wrote: >

>>Gene Wirchenko wrote:

*>>**>>>Bob Badour <bbadour_at_pei.sympatico.ca> wrote:**>>>**>>>>Gene Wirchenko wrote:**>>>>**>>>>>Bob Badour <bbadour_at_pei.sympatico.ca> wrote:**>>>>>**>>>>>[snip]**>>>>>**>>>>>>I admit I used epsilon somewhat sloppily and not necessarily with the**>>>>>>exact meaning used when discussing a particular floating-point**>>>>>>implementation. I used it to mean the distance to the representable**>>>>>>predecessor or successor of any representable rational value.**>>>>>**>>>>> That is incorrect. It is per**>>>>> http://en.wikipedia.org/wiki/Machine_epsilon**>>>>>In a floating-point system, epsilon is the smallest number such that**>>>>> 1 + epsilon > 1**>>>>>**>>>>>[snip]**>>>>**>>>>When you say the above is incorrect, are you saying I was not using**>>>>epsilon sloppily? Or are you saying I didn't use it to mean the distance**>>>>to the representable predecessor or successor of any representable**>>>>rational value?**>>>**>>> The definition of epsilon.**>>**>>Other than the "scaled by the exponent" bit, what exactly is the**>>difference? ie. If I subtracted one from the other, what answer would I get?*> > If I am understanding you, other than that difference, none. The > answer would be garbage.

I really don't understand your objection. I noted I used the term sloppily and not as defined for floating point when I was discussing rational representations. Using the only definition I gave for the floating point version, the difference would be zero. The definitions are equivalent only stated differently. Received on Thu Mar 29 2007 - 19:44:30 CEST