On Sunday, July 24, 2005 at 6:11 PM, Ken Barker wrote:
>
> What kind of post is this?
>
> I do not see that anything was added at all. Give us all a
> break - don't
> bother - whatever your intentions.
>
well, don't you feel stupid now?
>
> At 06:35 PM 7/24/2005, $Bill Luebkert wrote:
> >John Deighan wrote:
> > > At 02:20 PM 7/24/2005, Ed Chester wrote:
> > >
> > >
> > >>John Deighan::
> > >>
> > >>>Is there a safe way to compare 2 floating point numbers in Perl?
> > >>>[snip] My debugger says that they're both '630.24'
> [snip] However,
> > >>>the == test fails and the != test succeeds
> > >>
> > >>can you post code with the comparison == that fails ?
> > >>if the debugger says they're the same, they're very very probably
> > >>the same. are you sure the variable (or whatever) you're
> giving to
> > >>== are really what you want them to be?
> > >>there are lots of ways to compare numbers, right down to
> looping over
> > the bits
> > >>and logically
> > >>XNORing them.
> > >
> > >
> > > Sorry about the lack of sample code, but I know that
> people who work
> > > with floating point numbers know about this problem, and I was
> > > wondering what the best solution was. Here is sample code with
> > > output. Note that I'm not formatting the output or rounding or
> > > anything - just printing out the contents of the 2 variables.
> > >
> > > my $sum1 = -237.15;
> > > my $sum2;
> > > $sum2 += -26.35;
> > > $sum2 += -26.35;
> > > $sum2 += -26.35;
> > > $sum2 += -26.35;
> > > $sum2 += -26.35;
> > > $sum2 += -26.35;
> > > $sum2 += -26.35;
> > > $sum2 += -26.35;
> > > $sum2 += -26.35;
> > >
> > > print("sum1 = $sum1\n");
> > > print("sum2 = $sum2\n");
> > > if ($sum1 == $sum2) {
> >
> >You could try something like:
> >
> > if (abs ($sum1 - $sum2) < .0001) {
> >
> > > print("EQUAL\n");
> > > }
> > > else {
> > > print("NOT EQUAL\n");
> > > }
> > >
> > > OUTPUT:
> > >
> > > sum1 = -237.15
> > > sum2 = -237.15
> > > NOT EQUAL
> > >
> > >
> > > _______________________________________________
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> > >
> >
> >
> >--
> > ,-/- __ _ _ $Bill Luebkert
> Mailto:[EMAIL PROTECTED]
> > (_/ / ) // // DBE
> Collectibles Mailto:[EMAIL PROTECTED]
> > / ) /--< o // // Castle of Medieval Myth & Magic
> > http://www.todbe.com/
> >-/-' /___/_<_</_</_ http://dbecoll.tripod.com/ (My
> Perl/Lakers stuff)
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