18 lines
492 B
Perl
18 lines
492 B
Perl
use v5.36;
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use bigint;
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no warnings 'uninitialized';
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use List::Util 'max';
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use ntheory 'factor';
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sub table ($c, @V) { my $t = $c * (my $w = 2 + length max @V); ( sprintf( ('%'.$w.'d')x@V, @V) ) =~ s/.{1,$t}\K/\n/gr }
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sub D ($n) {
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my(%f, $s);
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$f{$_}++ for factor max 1, my $nabs = abs $n;
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map { $s += $nabs * $f{$_} / $_ } keys %f;
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$n > 0 ? $s : -$s;
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}
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say table 10, map { D $_ } -99 .. 100;
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say join "\n", map { sprintf('D(10**%-2d) / 7 == ', $_) . D(10**$_) / 7 } 1 .. 20;
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