Forums > MaxMSP

random seeds

May 10, 2006 | 11:28 am

Hi randomisers…

I know that random and urn can be seeded from a number dependent on the time since system start-up (seed 0) but I’m working on something that will start-up at the same time every day, and various parts of the program will be triggered at fixed times. This suggests that theoretically I could get the same sequence of events happening every day. < < or is this extremely unlikely?>>

To avoid this i just thought of generating the seed from sampling a piece of incoming audio (microphone) – remembering that some computer (atari1040ST?) used to provide random numbers by sampling some noisy piece of circuitry –

is there a simpler, cooler way to do this? do anyones externals generate random seeds in a different way?

– i looked in the archives but people seemed to be more interested in repeating a random sequence of events!

groeten, justin.

May 10, 2006 | 1:40 pm

you could use a prime number generatorr… i.e.

or use the output of the object itself multiplied by the cpuclock ?

May 10, 2006 | 5:59 pm

Hi Brian,

I was just about to say that I can’t see why either of your suggestions would make it more random. but now it suddenly dawns on me while typing: you’re right about the system clock because of course the date component is different every day.

But why Prime?

thanks, justin.

May 11, 2006 | 7:07 am

May 11, 2006 | 9:26 am

afaik computers report time since startup in ticks (1/60th of a second), so that would be unlikely, or at least unlikely to where the sequence might repeat once or twice a year, which you would be highly unlikely to notice. Personally I use the julian date&time.

May 11, 2006 | 9:51 am

yeah, once or twice a year no-one is going to notice!
Right now i’m making a seed by mangling the current date into
a useful number. justin.

May 11, 2006 | 10:00 am

maybe someone should modify the date + time object to accept the commands julian / orthodox / chinese / jewish / islamic / mayan / etc… in the interests of temporal diversity. ok, someone has probably done it already!

May 12, 2006 | 4:24 am

On around May 10, 2006, at 13:28, justin bennett said something like:
>is there a simpler, cooler way to do this? do anyones >externals generate random seeds in a different way?


The entire suite of Litter Power RNGs base their seed on multiple items drawn from the OS that will not repeat themselves. Ever. They also use an industrial-strength random number generator, rather than the Linear Congruence generator used by random and urn.

If you’re seriously interested in random numbers, you owe it to yourself to take a look at Litter Power. The Starter Pack is free. URI below.

Best, Peter

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Peter Castine (HTML doesn’t like the rest of this .signature)

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Forums > MaxMSP