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 Meaning of "seed" usage in defining PDF in VerilogA. 

Last post Fri, Jul 12 2013 3:31 AM by RFStuff. 2 replies.
Started by RFStuff 11 Jul 2013 09:09 AM. Topic has 2 replies and 499 views
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  • Thu, Jul 11 2013 9:09 AM

    • RFStuff
    • Top 25 Contributor
    • Joined on Tue, Feb 5 2013
    • Posts 250
    • Points 4,440
    Meaning of "seed" usage in defining PDF in VerilogA. Reply

     Dear All,

    Could anybody tell what is the function of seed parameter in a PDF in VerilogA.

    Any way we are giving mean.sigma value then I wonder what exactly the integer 'seed' does ?

     

    Kind Regards,

    • Post Points: 20
  • Thu, Jul 11 2013 2:52 PM

    Re: Meaning of "seed" usage in defining PDF in VerilogA. Reply

    Been rather busy (and out of the office today and tomorrow) so haven't been able to respond to questions - will only do a few this evening (I do have a life now and again too!). Please note (from your other posts) that if you have urgent questions, you should go to customer support, because we track service level targets there, rather than the forums which are an open forum for anyone (Cadence or the community) to contribute.

    I assume that "PDF" means something like "Probably Density Function"?. 

    Anyway, did you try searching for the word "seed" in the VerilogA reference manual? <MMSIMinstDir>/doc/veriaref/veriaref.pdf - it's fairly clearly described there. Seeds are used by random number generators to initialize the sequence of random numbers - for the same seed, the sequence will be the same - but changing the seed will give a difference sequence. In general you want repeatability from simulations so keeping the same seed is often wise (the same is true for Monte Carlo, for exactly the same reason). 

    The distribution (mean/sigma) will the the same (within accuracy limits for the number of points chosen), but the precise sequence of numbers will vary dependent upon the seed. That's all.

    Andrew.

    • Post Points: 20
  • Fri, Jul 12 2013 3:31 AM

    • RFStuff
    • Top 25 Contributor
    • Joined on Tue, Feb 5 2013
    • Posts 250
    • Points 4,440
    Re: Meaning of "seed" usage in defining PDF in VerilogA. Reply

     Dear Andrew,

    Thanks a lot.

    Kind Regards,

    • Post Points: 5
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Started by RFStuff at 11 Jul 2013 09:09 AM. Topic has 2 replies.