Oh - they are _good_ random numbers as well.... right from the first
number. We originally looked into it because the random number generator
on OSX doesn't give a good first random number. If you write a loop that
seeds with monotonically increasing reseeds and samples the first number...
those first numbers are _not_ random! This is normally not a problem
because you just seed once... but in our particular use case this was
causing "clustering" of our "random" results...
mtwist has no such problems. We've put it through the ringer and it gives
very good random distributions... right from the first number.
Derek
On Wed, Jan 23, 2013 at 3:56 PM, Derek Gaston <fried...@gmail.com> wrote:
> We've been using Mersenne Twist (mtwist) for a long time with very good
> luck. We can get the same random numbers across platforms and in parallel.
> VERY handy.
>
> http://fmg-www.cs.ucla.edu/geoff/mtwist.html
>
> Derek
>
>
> On Wed, Jan 23, 2013 at 2:41 PM, Roy Stogner <royst...@ices.utexas.edu>wrote:
>
>>
>> On Wed, 23 Jan 2013, Derek Gaston wrote:
>>
>> in our Python GetPot parser (yes, we have our very own because the
>>> official one is not great).
>>>
>>
>> Oh - in that case I should warn/inform you of another new feature: I
>> did also add a bunch of new DBE options, for cmath functions and
>> rand/srand. That should be even easier for you to port over, though.
>>
>> One thing I'm still thinking about w.r.t. the above: I'd like our PRNG
>> based results to be completely portable for reproduceability reasons,
>> but calling cmath rand(), the implementation is system-dependent.
>> Anyone know what the state of the art is for simple-as-possible
>> rand()-API-compatible PRNG algorithms, something we could just put
>> straight into getpot.h?
>> ---
>> Roy
>>
>
>
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