Thanks, looks like it's fallback (so called "div_scale", defaults to 40) value that was applied (and now I have a deja-vu to have already investigated this a few years back). Either of

use bignum p => 0;
bignum-> precision( 0 );
bignum-> div_scale( 999 );

[download]

(or method calls on an instance) will help. That still doesn't feel right:

use strict;
use warnings;
use feature 'say';
use Data::Dump;

use bignum; #use bigint;

say my $x = 999999999921778071482940061661655974875633165533182;
dd $x;

dd $x-> precision;
dd $x-> accuracy;
dd $x-> div_scale;
dd (Math::BigInt-> precision);
dd (Math::BigInt-> accuracy);

say my $y = $x / 1;

__END__

999999999921778071482940061661655974875633165533182
bless({
  sign  => "+",
  value => bless([165533182, 974875633, 61661655, 71482940, 999921778,
+ 999999], "Math::BigInt::Calc"),
}, "Math::BigInt")
undef
undef
40
undef
undef
999999999921778071482940061661655974875600000000000

[download]

But with bigint instead:

999999999921778071482940061661655974875633165533182
bless({
  sign  => "+",
  value => bless([165533182, 974875633, 61661655, 71482940, 999921778,
+ 999999], "Math::BigInt::Calc"),
}, "Math::BigInt")
undef
undef
40
undef
undef
999999999921778071482940061661655974875633165533182

[download]

i.e. object of the same class, with the same properties, same global parameters, but result is different. Same (per deja-vu) conclusion: avoid using bignum.

In reply to Re^3: bignum usage? by Anonymous Monk
in thread bignum usage? by rkd257

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.