Usually the programming languages used for those kind of programs have their own datatypes for ultra-high precision floating points. A 32 or 64 bit datatype is not enough for them anyway. They use all kinds of tricks/smart-assing to get around floating point rounding errors.
Walter On Sun, Sep 5, 2010 at 10:33, Raja Iskandar Shah <[email protected]> wrote: > i was also reading that article. but in that article, all the examples given > involves multiplication and divisions and exponents. this has been noted > before. > > the bug have the same root cause, but none has given a simple addition and > subtraction case example yet. it is just 4 numbers and 3 decimal places. > > the example test case is actual data from our ida application. fortunately, > the 12th decimal place is not significant. but imagine the problem occurring > in astrophysics or quantum mechanics, dealing with pie and prime numbers ! > > i wonder how is it handled in nuclear research and atomic super colliders ? > small error - but wham ! bang ! good bye world ! > > http://software.krimnet.com/cpu-precision-bug-plus-minus-operation.htm > > > On Sun, Sep 5, 2010 at 10:11 AM, Walter Heck - OlinData.com > <[email protected]> wrote: >> >> This is floating point rounding causing you hassles. Read this for >> more info: http://docs.sun.com/source/806-3568/ncg_goldberg.html (that >> gest very technical though :) ) >> >> On Sun, Sep 5, 2010 at 10:01, Raja Iskandar Shah >> <[email protected]> wrote: >> > guys, need some help testing this out >> > >> > taufiq has detected a bug involving a plus minus operations that should >> > result in zero but does not ! >> > >> > try the following in openoffice calc, ms excel, javascript, google calc >> > >> > =161001.165-100000.009-60000.7-1000.456 // will not return zero >> > >> > =161001.165+(-100000.009-60000.7-1000.456) // this does >> > >> > =((161001.165-100000.009)-60000.7)-1000.456 // and this not >> > >> > read the test case : >> > >> > http://software.krimnet.com/cpu-precision-bug-plus-minus-operation.htm#comment-491 >> > >> > so far we have tested on intel atom, intel core2, intel xeon >> > >> > need to see if the same problem happens on amd cpu >> > >> > >> > -- >> > Join Open Source Developers Club Malaysia http://www.osdc.my/ >> > >> > Facebook Fan page >> > >> > http://www.facebook.com/group.php?gid=98685301577 >> > >> > http://www.facebook.com/OSDC.my >> > >> > You received this message because you are subscribed to the Google >> > >> > Groups "OSDC.my Mailing List" group. >> > To post to this group, send email to [email protected] >> > To unsubscribe from this group, send email to >> > [email protected] >> > For more options, visit this group at >> > http://groups.google.com/group/osdcmy-list?hl=en >> >> >> >> -- >> Walter Heck >> Founder @ OlinData (http://olindata.com) >> >> -- >> Join Open Source Developers Club Malaysia http://www.osdc.my/ >> >> Facebook Fan page >> >> http://www.facebook.com/group.php?gid=98685301577 >> >> http://www.facebook.com/OSDC.my >> >> You received this message because you are subscribed to the Google >> >> Groups "OSDC.my Mailing List" group. >> To post to this group, send email to [email protected] >> To unsubscribe from this group, send email to >> [email protected] >> For more options, visit this group at >> http://groups.google.com/group/osdcmy-list?hl=en > > -- > Join Open Source Developers Club Malaysia http://www.osdc.my/ > > Facebook Fan page > > http://www.facebook.com/group.php?gid=98685301577 > > http://www.facebook.com/OSDC.my > > You received this message because you are subscribed to the Google > > Groups "OSDC.my Mailing List" group. > To post to this group, send email to [email protected] > To unsubscribe from this group, send email to > [email protected] > For more options, visit this group at > http://groups.google.com/group/osdcmy-list?hl=en -- Walter Heck Founder @ OlinData (http://olindata.com) -- Join Open Source Developers Club Malaysia http://www.osdc.my/ Facebook Fan page http://www.facebook.com/group.php?gid=98685301577 http://www.facebook.com/OSDC.my You received this message because you are subscribed to the Google Groups "OSDC.my Mailing List" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/osdcmy-list?hl=en
