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 Is there any recommended way to update instance parameters 

Last post Tue, May 13 2014 4:44 AM by Andrew Beckett. 1 replies.
Started by harishgurram 12 May 2014 08:10 PM. Topic has 1 replies and 202 views
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  • Mon, May 12 2014 8:10 PM

    Is there any recommended way to update instance parameters Reply

    Hi,

    Is there any way to update Pcell parameters without forcing to execute CDF Callbacks. The CDF Callbacks are taking more time to execute when i am forcing them to execute in a script. and for every parameter we are changing there is an associated callback withit. So we have to execute all the callbacks must ?

    I am using like this 

    callback=get(cdfGetInstCDF(car(geGetSelSet())  'w)~>callback

    evalstring(callback t)

    Is this is the right way?

    • Post Points: 20
  • Tue, May 13 2014 4:44 AM

    Re: Is there any recommended way to update instance parameters Reply

    There are several things that might be going on here. First of all, depending on the PDK, you may find that calling one of the callbacks is sufficient (at the end) if the callback is common to all and ensures consistency of all the parameters. Secondly the slowness might be due to the parameter changes causing re-evaluation of the pcell, including intermediate steps as each parameter is set.

    If you look at the code referenced in this recent post,  you'll see that abInvokeInstCdfCallbacks takes an argument ?order, so you can tell it which callbacks to call. So for example ?order list("w" "nf") would call just those two in that order.

    If you want to try to minimize the re-evaluation of the pcell, then I would do something like this:

     baseCDF=cdfGetBaseCellCDF(instId~>master~>cell)
     cdf=abCreateEffectiveCDFLookalike(baseCDF t)

    Then make your changes to cdf - so cdf~>w~>value="2u" or whatever your code needs to do to update it. For example:

     cdf~>w~>value=sprintf(nil "%g" w)
     cdf~>wf~>value=sprintf(nil "%g" w*nfingr)
     cdf~>l~>value=l
     cdf~>fingers~>value=nfing

    Then:

     abInvokeObjCdfCallbacks(cdf ?order '("w")) ; or whatever order you need

    And finally apply these to the instance:

    pcellParams=abConvertCdfToPcellParams(cdf)
    dbReplacePropList(instId pcellParams)

    I haven't checked recently (and this probably depends on the version you're using), but I think dbReplacePropList avoids multiple pcell evaluation.

    Note I haven't exactly used the above before - I've used similar within a hierarchical pcell though.

    Regards,

    Andrew.

    • Post Points: 5
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Started by harishgurram at 12 May 2014 08:10 PM. Topic has 1 replies.