On 2012-10-21, LFS <[email protected]> wrote:
> ------=_Part_1134_6290611.1350821044307
> Content-Type: text/plain; charset=ISO-8859-1
>
> yes - i finally saw that and took the call to the GDDinit out of the loop 
> and this may be working, but I don't know how to explain this to the 
> kiddies. 
Just tell them the truth,  as we all should be telling our
students. :-)
Explaining to them what pseudorandom numbers (and why it's hard to
get "true" random numbers from computer) are is much more
useful, and easier than that very advanced (and I am a professional
mathematician, you know) stuff you are trying to talk about...
At least the concept : you have a (very long, but finite) cyclic
sequence of numbers, and you draw from this sequence starting from the 
the place determined by the seed, is much easier than non-finite
probability.

> Probably should have just stuck with Excel where I understand the 
> generators. Too complicated by far.

Hmm, what do you mean? IMHO, until this conversation here, you did not
know why it actually works in excel! 
What excel does behind the scene is initializing the
random seed from system time, at least that's what rumours on the net
say. In it's usual sloppiness, M$ does not bother to document this. 
How one can trust computations done with this piece of software, I have
no clue. 
Must be church-like indoctrination, no less :-) 
Just make sure that your copy of M$ Office is paid for, 
and it will work, by magic. If my kid was in a class like this,
I'd have had very serious objections to the teacher.

Cheers,
Dmitrii

> Thanks everyone for your help.
>
> On Sunday, 21 October 2012 13:56:06 UTC+2, Dima Pasechnik wrote:
>>
>> On 2012-10-21, LFS <[email protected] <javascript:>> wrote: 
>> > ------=_Part_87_6472836.1350820122321 
>> > Content-Type: text/plain; charset=ISO-8859-1 
>> > 
>> > Actually Dmitrii with this change it is giving me exactly the same 
>> > empirical data each time! 
>>
>> well, I just gave you a general framework for initializing and using a 
>> pseudo-random number generator. 
>> If you initialize it with the same seed, you get the same pseudo-random 
>> sequence. (sometimes uselful, if you want to check that you get the 
>> same results from seemingly random computation) 
>> So if you restart your computation from the very beginning, inclusing 
>> the initializing of the random seed with the same value, you will get 
>> the same data each time you do the computation. 
>>
>> But if you want to emulate true randomness, you only have to initialize 
>> the seed once. 
>>
>> HTH, 
>> Dmitrii 
>>
>>
>

-- 
You received this message because you are subscribed to the Google Groups 
"sage-support" group.
To post to this group, send email to [email protected].
To unsubscribe from this group, send email to 
[email protected].
Visit this group at http://groups.google.com/group/sage-support?hl=en.


Reply via email to