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Spectre Error during Monte-Carlo

ajbluestone

I've got Monte-Carlo simulations working on very basic circuits, let's say an NMOS FET with its Gate/Drain shorted and an ideal current source pumping current into that node.  My models support Monte-Carlo and I can see a gaussian distribution for Vgs across 200 samples (DC Analysis).  As soon as I create a current mirror, adding a second transistor's gate to this node, the monte-carlo runs fail to complete.

Actually, the monte-carlo completes several runs successfully, then fails about 50 in a row, then completes several successfully again, and so on..

The Simulation Error Message for each of the failures reads:

ERROR (Spectre-20093): disk I/O error (error code is '10')

I can't find any additional information on what this error means.  My machine has plenty of disk space and routinely handles lengthy transient sims or more difficult DC operating points.

I've tried this in both ADEXL and ADE Explorer, same error.

Virtuoso 6.1.8-64b

Spectre 18.1.0.143.isr1 64bit

  • Andrew Beckett

    I found a report of a similar issue (CCR 2036867 and 2025620 for my reference), and it's implied that this is fixed in SPECTRE18.1 ISR5. So please move to a more recent SPECTRE hotfix and see if that resolves it. The issue is related to the saving of the checks/asserts (probably in  your model files) - you could probably workaround it by going to Simulation->Options->Analog, Check tab, and then setting dochecklimit to no. That will turn off the asserts and so it won't try to save these to an SQL database (but it does mean that it won't be doing those checks if they are important to your flow). I don't know for certain that will workaround it, but I think it should...

    Regards,

    Andrew.

  • ajbluestone
    in reply to Andrew Beckett

    Thank you, Andrew!  This workaround seems to do the trick until I can get an updated SPECTRE.

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