and rand share a seed while tandom may have independent seeds



Quoting jpff@cs.bath.ac.uk:

> random uses
>
> #define oneUp31Bit      (4.656612875245796924105750827168e-10)
> val = (((val* 214013 + 2531011) >> 1) & 0x7fffffff) * oneUp31Bit
>
>
> rand uses one of two algorithms -- selectable
>
> Original is
> #define RNDMUL  15625
>           rand *= rndmul;
>           rand += 1
>
> New is
> f(z) = (16807 * z) mod (2 ** 31 - 1)
>  *  Based on "Random Number Generators: Good Ones Are Hard to Find",
>  *  S.K. Park and K.W. Miller, Communications of the ACM 31:10 (Oct 1988),
>  *  and "Two Fast Implementations of the 'Minimal Standard' Random
>  *  Number Generator", David G. Carta, Comm. ACM 33, 1 (Jan 1990), p. 87-88
>
> I believe rand with new algorithm is high quality
>
> On some machines you can get true random with urandom
>
> ==John
> Quoting mskala@ansuz.sooke.bc.ca:
>
>> On Mon, 17 Feb 2014, Paul Batchelor wrote:
>>> random* lets you specify specific max/min ranges.
>>>
>>> rand* does values between 0 and 1
>>
>> The rand* opcodes also seem to allow adjusting the bounds using the
>> amplitude and offset arguments.  But that's what I meant by syntax
>> differences.  Are there any more substantive differences, for instance in
>> the PRNG algorithms used?
>>
>> --
>> Matthew Skala
>> mskala@ansuz.sooke.bc.ca                 People before principles.
>> http://ansuz.sooke.bc.ca/
>>
>>
>> Send bugs reports to the Sourceforge bug trackers
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>> "unsubscribe csound"
>
>
>
>
>
> Send bugs reports to the Sourceforge bug trackers
> csound6:
>            https://sourceforge.net/p/csound/tickets/
> csound5:
>            https://sourceforge.net/p/csound/bugs/
> Discussions of bugs and features can be posted here
> To unsubscribe, send email sympa@lists.bath.ac.uk with body  
> "unsubscribe csound"