With the forthcoming improved C interface (heavy hint to Clint here) you should
also be able to use the random routines in the GSL, which may solve some of
these problems.
I use their Mersenne twister in some of my code.
Kostas
Sent from my iPhone
On Feb 3, 2012, at 10:04 AM, Phillip <p...@firefly.nlm.nih.gov> wrote:
> Yes, we finally(!) about a year ago set the normal random by default not
> to always produce the same number -- this is true in the UNIX versions, I
> believe, but I don't know if it reached the windows side. My argument was
> that having the default always produce the same number was only useful in
> some testing situations but never in any production program. The problem
> here -- if you accept my random philosophy -- is that the results are too
> clustered.
>
> I had a physicist friend who was about ready to present a paper with
> startling results (different operation system than available now and not
> Unicon) only to find that the random number generation was giving the same
> value each time. He had to withdraw his paper. From this experience, I've
> never trusted my off-the-top-of-my-head, post-midnight, kludges to produce
> a random seed adequately for a given task, assuming that I even remembered
> to randomize the randomizer.
>
> --Phillip
>
>
> On Thu, 2 Feb 2012, Jafar
> Al-Gharaibeh wrote:
>
>> Hi David,
>>
>> I believe &random is the seed and not to be confused with the random
>> sequence you would get if you use the "?" operator. &random probably gets
>> its initial value using the system clock with some simple math. That is why
>> you have numbers (seeds) that are all clustered together since probably you
>> ran the program several times around the same clock. If you want the same
>> sequence to be repeated, set &random at program start up to a specific
>> value, zero for example, but if you want random numbers you can do
>> something like
>>
>> ?x # where x is 10^6 for example to get numbers in the range of [0 :
>> 10^6-1 ]
>> # (have to double check if I got the boundaries right)
>>
>> In any case, the Unicon book seems to be inconsistent about whether the
>> value of &random is "randomly" set at start up or not. I believe it is.
>>
>> Jafar
>>
>>
>>
>> On Thu, Feb 2, 2012 at 3:59 PM, David Gamey <david.ga...@rogers.com> wrote:
>>
>>> Hi Folks,
>>>
>>> I know the built-in PRNG is a bit quirky and as I understand it Unicon
>>> departed from Icon by randomizing it initially (although UB3/Sesrit
>>> contradicts this).
>>>
>>> If I run this several times on Win7/x64 UniconV12:
>>>
>>> procedure main();write("&random=",&random);end
>>>
>>> I get only minor variations:
>>>
>>> &random=20122651
>>> &random=20122851
>>> &random=20123251
>>> &random=20123351
>>> &random=20123451
>>> &random=20122961
>>> &random=20123161
>>> &random=20123261
>>> &random=20123361
>>> &random=20123461
>>>
>>> Does anyone have any idea what is supposed to happen?
>>>
>>> This doesn't help much for testing (fixed &random) or for simulation
>>> (random &random)
>>>
>>> David
>>>
>>>
>>>
>>>
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>>
>>
>> --
>> "Let there be no compulsion in religion: Truth stands out clear from error"
>> [The Holy Qur'an 2:256]
>>
>> "Injustice anywhere is a threat to justice everywhere" Dr. King
>>
>
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