[Scottish] allowing a large newborn sea-mammal to collide with a rocky plane toid object devoid of atmosphere somewhere in another galaxy

[Colin Fraser]

---- Original Message ----
From: allan@whiteford.org.uk
To: scottish@mailman.lug.org.uk
Subject: Re: [Scottish] allowing a large newborn sea-mammal to
collide with a rocky plane toid object devoid of atmosphere somewhere
in another galaxy
Date: Fri, 21 Mar 2003 09:48:39 -0000 (GMT)

>> On Fri, 2003-03-21 at 09:06, John Hallam wrote:
>>> On Thu, 20 Mar 2003, Huard, Elise - D C&W Consultant wrote:
>>>
>>> > Or to phrase it differently : i need a random number generator
>that
>>> won't give the same sequence of numbers every time that the seed
>is
>>> reinitialised in the same second (by 2 different users)
>>> > srand(time(NULL))
>>> > and then rand()
>>> > doesn't work.
>>> > Or a different kind of seed ?  Suggestions are welcome (should
>be
>>> readily available in your standard Unix system)
>>>
>>> 	One thing you can do is to execute `ps' and hash the output, e.g.
>>> with MD5, and use some of those bits as your seed.  There is
>enough
>>> going on in a PS output to make duplicate seeds rather unlikely,
>>> unless (perhaps) you have a multiple CPU machine which can execute
>>> multiple ps invocations simultaneously...
>>>
>>> 	As someone else said, be careful with rand() if you want good
>>> random sequences -- some rand()s are seriously broken.  A good
>cheap
>>> random number generator is the Mersenne Twister, which you can
>find at
>>> http://www.math.keio.ac.jp/~matumoto/emt.html
>>>
>>> 	John.
>>
>> A white noise source connected to the sound card input would be a
>good
>> truly random number generator.
>>
>
>Now all we need to be able to do is create a true white noise source.
>Probably the best way to achieve this is to get a computer with a
>good
>software random number generator to produce random numbers and output
>them
>from a soundcard :).
>
Alternately we could just select anythng from this list and hash
that. Of course the selection would have to be at random .... ;-)

Colin (the other one).