[Newbies] Randomness

[michael rice]

Thanks again. I'll just modify the seed each time, before I load the project, and get different results that way.

Michael

--- On Mon, 4/4/11, Levente Uzonyi <leves at elte.hu> wrote:

From: Levente Uzonyi <leves at elte.hu>
Subject: Re: [Newbies] Randomness
To: "A friendly place to get answers to even the most basic questions about Squeak." <beginners at lists.squeakfoundation.org>
Date: Monday, April 4, 2011, 8:32 PM

On Mon, 4 Apr 2011, michael rice wrote:

> I forgot to mention, I'm using the random number tile and scripting. Does that make it more difficult?

Not really, RandomNumberTile uses the global random number generator of Collection. I don't know how/why is it serialized/restored, but here's a method which should help:

RandomNumberTile >> #comeFullyUpOnReload: smartRefStream

    | seed |
    [
        seed := (Time millisecondClockValue bitAnd: 16r3FFFFFFF) bitXor: self hash.
        seed := seed bitXor: (Time totalSeconds bitAnd: 16r3FFFFFFF).
        seed := seed bitXor: 16r3FFFFFFF atRandom.
        seed = 0 ] whileTrue. "Try again if ever get a seed = 0"
    Collection mutexForPicking critical: [
        Collection randomForPicking seed: seed ].
    ^super comeFullyUpOnReload: smartRefStream

It's drawback is that it will reseed the rng for every RandomNumberTile. The best solution would be if Etoys would use a custom Random instance or a subclass where this is done by default.


Levente

> 
> Michael
> 
> --- On Mon, 4/4/11, Levente Uzonyi <leves at elte.hu> wrote:
> 
> From: Levente Uzonyi <leves at elte.hu>
> Subject: Re: [Newbies] Randomness
> To: "A friendly place to get answers to even the most basic questions about Squeak." <beginners at lists.squeakfoundation.org>
> Date: Monday, April 4, 2011, 8:08 PM
> 
> On Mon, 4 Apr 2011, michael rice wrote:
> 
>> I just noticed that when I load a morphic project I get the same stream of random numbers each time. Is there a simple way to install a new different random seed each time the project is loaded?
> 
> If you serialize the Random object, then it will have the same state when it's restored. I guess you should create a subclass of Random, which implements #comeFullyUpOnReload:. That method can reinitialize the seed of the random number generator. You may want to check UUIDGenerator >> #makeSeed if you don't know how to get a good seed for your rng.
> 
> 
> Levente
> 
>> 
>> Michael
>> 
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