in reply to Re^3: In-place sort with order assignment
in thread In-place sort with order assignment

On your computer?

No! 

#! perl -slw
use strict;

our $N //= 10e6;

my %hash;
my $val = 'AAAAA';

undef $hash{ $val++ } for 1 .. $N;

my $start = time;

open SORT, '| sort > sorted' or die $!;
print SORT $_ while $_ = each %hash;
close SORT;

undef %hash;

open IN, '<', 'sorted' or die $!;
chomp(), $hash{ $_ } = $. while <IN>;
close IN;

my $elapsed = time - $start;

printf "Took %.6f seconds for $N items (%.5f per second)\n",
    $elapsed, $elapsed / $N;


__END__
C:\test>junk41 -N=10e6
Took 225.000000 seconds for 10e6 items (0.00002 per second)

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Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
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In the absence of evidence, opinion is indistinguishable from prejudice.
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Re^5: In-place sort with order assignment
by rowdog (Curate) on Sep 20, 2010 at 22:37 UTC

    Not that this seems to help you very much but sort was my first instinct too. My rather dated Debian Squeeze box is an AMD 3800+ (64 bit dual core) with 2 gigs RAM and one 5 year old IDE drive can almost do it.

    $ perl 860849.pl
Took 131.000000 seconds for 10000000 items (0.00001 per second)

    [download]

    I think I could reach that 108 by putting the sorted file on a separate spindle with a thinner filesystem layer (e.g. no ext3 and LVM2).

    I'm really pointing this out because it's quite attainable with a reasonably recent hard drive. Maybe even just SATA/PATA would do the trick. SSD surely would.

[reply]
[d/l]

      My next intended purchase is a cheap (sub £50), small capacity (32 or 64GB) SSD. {This is the closest Ive seen so far.)

      An external sort would definitely become a viable option if I could use that for the temporary files.

[reply]

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