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How to find the period of $urandom generator of Xcelium

nustisb1

I am trying to find the period( repetition of sequence) of $urandom generator but cannot calculate it is taking too much simulation time. can anyone tell me the period of the random number generator or after how many random sequences it will repeat sequence? and how I can find it.

  • It's a pseudo-random generator (the SystemVerilog standard does not say how it should be implemented) and any period will be absolutely huge (far bigger than you are likely to be able to simulate). Why are you worried about that? I don't think it's documented or even likely to have a predictable period (that may depend on the seed - I don't know, but it might).

    Andrew

  • in reply to Andrew Beckett

    Thanks, Andrew Beckett. Yes, you are right the period will be huge. I just want to know the limit of random sequences before it will start repetition in the case without seed.

  • in reply to nustisb1

    Well, I don't know for certain, but if the implementation uses the C random function which generates a 32-bit integer, that is documented as having a period which is approximately  16 * ((2^31) - 1) . I don't really understand why it matters - I'd be surprised if in any practical case you'd ever get through a cycle that large. If you really need to know, I think you'd need to ask customer support who in turn would need to ask R&D.

    Regards,

    Andrew

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