Re^5: How do I make a random shuffle deterministic?

in reply to Re^4: How do I make a random shuffle deterministic?
in thread How do I make a random shuffle deterministic?

New try after some research.

use Sys::Hostname;
use Digest::MD5 qw( md5 );

sub seed {
    my $string = shift;
    my $seed = 0;

    my $digest = md5( $string );
    
    for ( split //, $digest ) {
        $seed = ( $seed * 256 + ord ) % 1e12;
    }

    srand $seed;
}

# main matter
my $hostname = hostname;
seed ( $hostname );
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Comment on Re^5: How do I make a random shuffle deterministic? Download Code

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Re^6: How do I make a random shuffle deterministic? by LanX (Saint) on Dec 06, 2012 at 15:31 UTC
Looks fine for me! The modules are core and your producing a maximal seed. Still think it's exaggerated for your problem... ... but it's a good generic solution for similar tasks! =) My only concern is readability, better use something like `ord $char` with an explicit loop var `my $char` Anyway you are still operating on the assumption that hostnames are always different, since I don't know your project this might be ok or not. Generating a random seed at installation time would prevent this "problem". Cheers Rolf	[reply] [d/l] [select]

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Re^6: How do I make a random shuffle deterministic?
by LanX (Saint) on Dec 06, 2012 at 15:31 UTC

The modules are core and your producing a maximal seed.

Still think it's exaggerated for your problem...

... but it's a good generic solution for similar tasks! =)

My only concern is readability, better use something like ord $char with an explicit loop var my $char

Anyway you are still operating on the assumption that hostnames are always different, since I don't know your project this might be ok or not.

Generating a random seed at installation time would prevent this "problem".

Cheers Rolf

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