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polettix (7564)
Tuesday February 20, 2007
06:43 PM
The Sieve of Eratosthenes
Translating a python function for a sieve of eratosthenes (a way to detect prime numbers), I've come up with this:
sub eratosthenes {
my %D;
my $q = 2;
return sub {
while (defined(my $p = delete $D{$q})) {
my $x = $p + $q;
$x += $p while exists $D{$x};
$D{$x} = $p;
++$q;
} ## end while (defined(my $p = delete...
$D{$q * $q} = $q;
return $q++;
};
} ## end sub eratosthenes
It's nice, even if it tends to blow for increasing values (due to memory requirements).
about I/O disciplines and I should retire to the Tassili-in-Aijer
mountains in Sahara as a camel herder :-)
-- Jarkko Hietaniemi
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