> On Jun 11, 2022, at 4:41 AM, ToddAndMargo via perl6-users
> <perl6-us...@perl.org> wrote:
>
> Hi All,
>
> In the following paper on Big Root:
>
> https://newbedev.com/how-can-i-set-the-level-of-precision-for-raku-s-sqrt
>
>
> > use BigRoot;
> > BigRoot.precision = 7;
> > say (BigRoot.newton's-sqrt: 2;).base(10)
> 1.4142136
> > say (BigRoot.newton's-sqrt: 2;).base(16)
> 1.6A09E7
>
> That is a base(10) precision. In base(16) (Hex)
> that is only 3 digits past the decimal.
> 0x6A-0x09-0xE7
>
> Is there a way to tell BigRoot I want a certain
> amount of Hex digits I want after the decimal?
No, https://github.com/juliodcs/BigRoot/blob/master/lib/BigRoot.rakumod shows
that BigRoot only allows setting precision as decimal.
> Or just ask for double I want and prune afterwards?
Doubling your desired precision is overkill; you only need a 21% increase.
Since:
decimal_precision =~= ( hexadecimal_precision_wanted * log(16) / log(10) );
, this should work:
BigRoot.precision = ( $hexadecimal_precision_wanted * log10(16) ).ceiling;
As evidence:
my $hexadecimal_precision_wanted = 2 ** 13;
my $decimal_precision_via_log = ( $hexadecimal_precision_wanted *
log10(16) ).ceiling;
my $largest_hex_number_that_size = 'F' x $hexadecimal_precision_wanted;
my $decimal_precision_via_chars =
$largest_hex_number_that_size.parse-base(16).chars;
.say for ( :$hexadecimal_precision_wanted, :$decimal_precision_via_log,
:$decimal_precision_via_chars );
Output:
hexadecimal_precision_wanted => 8192
decimal_precision_via_log => 9865
decimal_precision_via_chars => 9865
--
Hope this helps,
Bruce Gray (Util of PerlMonks) [who just learned of the BigRoot module]
