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Postings from October 2003
On Wed, Oct 08, 2003 at 10:09:28PM -0400, Ed Allen Smith <easmith@beatrice.rutgers.edu> wrote:
> In message <20031009011103.GA3456@efn.org> (on 8 October 2003 18:11:03
> -0700), sthoenna@efn.org (Yitzchak Scott-Thoennes) wrote:
>
> >How about this:
> >
> >--- lib/Math/BigInt/Calc.pm.orig 2003-10-08 15:31:26.583782400 -0700
> >+++ lib/Math/BigInt/Calc.pm 2003-10-08 15:43:00.251227200 -0700
> >@@ -1423,7 +1423,10 @@
> > else
> > {
> > # fit's into one Perl scalar, so result can be computed directly
> >- $x->[0] = int( $x->[0] ** (1 / $n->[0]) );
> >+ my $result = int( $x->[0] ** (1 / $n->[0]) + .5);
> >+ # see if we rounded up inappropriately
> >+ --$result if $result ** $n->[0] > $x->[0];
> >+ $x->[0] = $result;
> > }
> > return $x;
> > }
> >End of Patch.
>
> I like it overall, except that I'm wondering given rounding wierdnesses
> whether it might be best to check specifically what the result is without
> the +.5.
Not sure exactly what you mean. The rounded value will either be
the truncated result or one more than it.
That way, if something goes wrong with the $result**$n->[0] check
> (say it's 0.000000001 greater than $x->[0]), it'll just revert to the
> behavior without the +0.5.
You shouldn't get that kind of inaccuracy with an integer ** integer
calculation. Nevertheless, I guess you could say:
--$result if int($result ** $n->[0] + .5) > $x->[0];