my point is, even these kind of "comparison" error due to rounding etc should not have cause your heuristics to go haywire. If your heuristics is so sensitive, something else is wrong. If you can illustrate with an example, that might be good. For the kind of heuristics I have seen, they don't matter. Sun
On Sun, Aug 5, 2012 at 1:58 AM, Gilmore, Doug <doug.gilm...@amd.com> wrote: > I was looking into other issues yesterday so I was sidetracked. >> -----Original Message----- >> From: Sun Chan [mailto:sun.c...@gmail.com] >> Sent: Saturday, August 04, 2012 3:24 AM >> To: Gilmore, Doug >> Cc: "C. Bergström"; open64-devel >> Subject: Re: [Open64-devel] Review request: fixing issues when building >> the compiler as 64-bit binaries >> >> I haven't had any real code segment to explain why the change to float >> to double is needed for the claim, i.e. enable 64bit porting, and >> better precision. I have to do this in the abstract. >> I don't see any relationship between float and double to 64 bit >> porting. As for precision, the example given is "probability". For >> compiler optimization, it is true that probability is widely used to >> help heuristics, but I have yet to see an example where one needs >> beyond 2 decimal point precision. > If actually had 2 decimal point precision float point arithmetic, then > you would need to be extremely careful to insure that there were no > reordering of FP operations. Otherwise there would be enough noise in > the calculations to produce different FP comparison results. > > I am still collecting data on this. > > Sorry for the delay. > > Doug >> I'm gonna have to say, this change from float to double is not useful >> other than making data size larger, which is in general not a good >> thing. >> Sun >> >> On Fri, Aug 3, 2012 at 7:38 AM, Sun Chan <sun.c...@gmail.com> wrote: >> > for the float/double issue, can you include a code snippet that will >> > affect by this change (you have mentioned probability, for example) >> > Thx! >> > Sun >> > ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Open64-devel mailing list Open64-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/open64-devel
