in reply to Using Perl to simulate evolution.

Thinking about your idea here led me to consider how one would feed randomness into your model, as of course
one of the key points of evolutionary theory is "random mutation".

My understanding is that it is not possible to get true randomness in a program using a seed value and the "rand()"
type functions that can be found in programming languages.

Connecting some type of device such as a Geiger counter to a PC and sampling the output of such a device is certainly
one way to get truly random numbers. I am wondering if anyone else has used something else such as stock price changes, as according to finance theory stock prices change in a "random walk". Putting code together to grab stock prices has obviously
been done before, but I wonder if anyone has done so for the purpose of extracting random values.

Update 04-04-06: A readable and informative document titled "Cryptographic Random Numbers" by Carl Ellison can be found here.

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Re^2: Using Perl to simulate evolution.
by zentara (Cardinal) on Mar 16, 2006 at 13:20 UTC
    Personally, I think "randomness" is like Anthropomorphism. (giving human attributes to the "gods" to make our understanding easier). In many contexts, randomness is something we have attributed to Nature, in order to use our statistical models. That doesn't mean that Nature works at random, but it appears that way to us, and our puny mathematical models.

    So I think you can get a fairly good random motion model, by taking rand(360), to determine which way something should move. Of course, this gets to the crux of the model. What factors will modify that rand(360) value? Water flow? Chemical concentrations in certain areas, etc,etc. This sort of thing will probably need "fudge factor constants" at first, so that the model will reflect what is actually observed. But as understanding increases, those fudge-factors will become computable variables. Or......

    use God qw('hidden hand'); # ;-)

    I'm not really a human, but I play one on earth. flash japh
[reply]
      Your points are reasonable. The first one leads to a deeper discussion than I'd want to be in on this site:)...
[reply]

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