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using steppreset as part of dynamic parameter vector

david73

I can successfully use stepparam as a dynamic variable on its own, but when i try to insert it as part of a setof variables, i get a simulation error

ERROR: Unknown parameter `lx' has been specified in expression `lx'
ERROR: Unknown parameter `cx' has been specified in expression `cx'

  • This is a known limitation currently. Change request (CCR) 2755025 is asking for this, and it's currently planned for SPECTRE21.1 ISR21. Note that even if you use the numerical equivalent of steppreset values, it still doesn't work. Note too that when varying steppreset you should always start the simulation (using +preset=XX) with the most conservative that you're going to use through the simulation, as any reduction/optimization is done at the beginning and you can't undo it during the simulation...

    Andrew

  • in reply to Andrew Beckett

    Thanks! in the High performance simulation setup, there are two options, Accuracy + speed, with options from VX to CX, and parasitic optimization, from VX to CX, Are you saying that both should be set to the highest level accuracy that will be used during simulation, or only parasitic optimization?

  • in reply to david73

    It's mainly the parasitic optimisation that needs to be set to the most conservative that you're going to need throughout the simulation, since that's going to affect the amount of reduction performed. In general you should (by default at least) just set preset (and postlpreset is set to the same automatically). That said, I'd probably just set preset to the most conservative you need unless there's a very good reason not to. There's also no problem with setting the preset to (say) cx because you're going to use that later, and then set to lx at time zero via steppreset.

    Andrew

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