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Multiple set of save statements in spectre simulation

shankarp
I am doing a PSS simulation of an oscillator with spectre which runs for pretty long duration for the oscillation to stabilize. I want to monitor/save only 4 nodes (say x1,x2,x3,x4) in the tran part of the PSS to prevent blowing up of the simulation data size. In the steady state PSS solution I wanted to save many nodes in addition to the said four nodes(x1,x2,x3,x4). Is it possible to save two different set of nodes for the tran part and steady state part in spectre?

I attempted the following solution:

save x1 x2 x3 x4
pss_run_aux  (x1 x2) pss fund=var_fosc harms=200 errpreset=conservative save=selected annotate=status tstab=3m saveinit=yes relref=alllocal writepss="%C_tran.pss" strobeperiod=1/(16*var_fosc)
pss_run      (x1 x2) pss fund=var_fosc harms=200 errpreset=conservative save=all annotate=status tstab=3m saveinit=no relref=alllocal readpss="%C_tran.pss"
removeTranpss shell cmd="rm -f %C_tran.pss" annotate=status
 
The first PSS(pss_run_aux) runs the tran part in which I save the four nodes in the raw directory. The second PSS(pss_run)starts from the data written by the previous analysis to compute the steady state pss data. However, I was not able to specify a seperate set of nodes to be saved for the second PSS analysis(pss_run) and I end up writing save=all.
 
Is there a way to save two different types of node sets for two different analysis within the same netlist?
 
Thanks in advance.

  • Hi Shankar,

    I don't believe this is possible. It's certainly not possible between the saveinit and shooting phase of the PSS. I did try using either a dummy alter statement between the two pss runs that you'd tried, but the save statements are effectively global and not ordered.

    I also tried putting the save statement in an altergroup, but that's not supported.

    So I think this is a good idea though - so please contact customer support and request an enhancement to provide a way to do this. Probably we need something like a "queued" save statement (similar to the "set" statement which is a queued options statement), where the save statement would be run in order like the analyses are.

    Regards

    Andrew.

  • Hi Andrew,

    I have also tried the alter/altergroup statements in the first place to vain.  As you suggested let me suggest an enhancement through the customer support. 

    Thanks

    Shankar 

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