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From: Mirco Wahab on 2 Apr 2008 07:18
vivekanand.naik(a)gmail.com wrote:
> printf("%.32g\n",0.99999999976716936);
>
> Perl 5.6.1 output:
> 0.99999999976716936 --> GOOD
>
> Perl 5.8.6 output:
> 0.99999999976716925 --> ERROR
> Any reason for such mismatch ?
> Please let me know how to avoid that or any alternative approach if
> any.

This is in the interval from 1e-16 to 1e-15, which
is the accuracy of a IEEE 8 byte double in this
number range (52 bits for fraction). Seems to
be ok ==> 1 / (2^52).
The correct result (above) needs (imho) longer
than 8 byte doubles, like

perl -MMath::BigFloat -e'print Math::BigFloat->new("0.99999999976716936")->bstr()'


Regards

M.

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