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QPSS QPAC Simulation Failure due to insufficient memory (Read 8784 times)
aaron_do
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QPSS QPAC Simulation Failure due to insufficient memory
Mar 09th, 2010, 11:00pm
 
Hi all,


I'm trying to simulate the IIP3 of a down-conversion system, but the simulation always fails due to insufficient memory. In the QPSS options, I enabled a swapfile (there's around 13 GB free space in that drive), and I enabled compression, and I only saved the selected nets. Is there anything else I can do to get the simulation to finish. Note that my run directory has about 13 GB of free space, and the computer's memory is 3 GB. The output log file always says the following:

Mem Used: 3056.9 MB (Memory Exhausted)
Warning from spectre during IC analysis, during periodic steady state analysis, during Quasi-Periodic Steady State Analysis `sweepqpss-002_qpss', during Sweep analysis `sweepqpss'.
   WARNING (SPECTRE-16001): Sweep iteration for `prf' = -60 terminated prematurely because of the following error(s):
Fatal error found by spectre during IC analysis, during periodic steady state analysis, during Quasi-Periodic Steady State Analysis `sweepqpss-002_qpss', during Sweep analysis `sweepqpss'.
   FATAL (CMI-2002): Insufficient memory available, To reduce memory for rf analyses, please refer "spectre -h rfmemory".


I can't seem to find this spectre -h rfmemory either...


thanks,
Aaron
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pancho_hideboo
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Re: QPSS QPAC Simulation Failure due to insufficient memory
Reply #1 - Mar 10th, 2010, 2:10am
 
aaron_do wrote on Mar 9th, 2010, 11:00pm:
I'm trying to simulate the IIP3 of a down-conversion system

Which engine do you use for QPSS, Shooting-Newton or HB ?

Show me "Circuit inventory" informations in log file.
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« Last Edit: Mar 10th, 2010, 4:18am by pancho_hideboo »  
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aaron_do
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Re: QPSS QPAC Simulation Failure due to insufficient memory
Reply #2 - Mar 10th, 2010, 7:37pm
 
Hi pancho_hideboo,


I am using the default method which seems to be the Shooting-Newton method.

Here is the circuit inventory. It is a post-layout simulation, so its pretty large. Now that I look at it i'm not sure why there are so many inductors. I only did a C+CC extraction.

Circuit inventory:
             nodes 4253
             balun 1    
           bsim3v3 8352  
         bsource_1 14    
         capacitor 18667
             diode 182  
          diode_va 32    
          inductor 359  
   mutual_inductor 6    
              port 4    
          quantity 9    
            res_va 256  
          resistor 2203  
           vsource 9    

thanks,
Aaron
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pancho_hideboo
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Re: QPSS QPAC Simulation Failure due to insufficient memory
Reply #3 - Mar 11th, 2010, 12:52am
 
aaron_do wrote on Mar 10th, 2010, 7:37pm:
Here is the circuit inventory.
It is a post-layout simulation, so its pretty large.
Now that I look at it i'm not sure why there are so many inductors.
I only did a C+CC extraction.
Not so large.

I'm using HB2SS(=2 large tones with one small signal HB Analysis) of Agilent ADSsim and GoldenGate for IP3 evaluation of more large circuits.

aaron_do wrote on Mar 10th, 2010, 7:37pm:
I am using the default method which seems to be the Shooting-Newton method.
Use HB not Shooting-Newton.

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aaron_do
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Re: QPSS QPAC Simulation Failure due to insufficient memory
Reply #4 - Mar 11th, 2010, 4:51am
 
Quote:
Use HB not Shooting-Newton.


thanks. I'll give it a try


Aaron
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Andrew Beckett
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Re: QPSS QPAC Simulation Failure due to insufficient memory
Reply #5 - Mar 11th, 2010, 8:46am
 
The other common mistake people make is related to specification of the tones in QPSS. This works by using the "Frequency Name" on the sources to identify the frequencies of the tones. What you should do is specify any sources with common frequencies (maybe they have different phases) as having the same frequency name. This means that it will not treat them as independent frequencies in QPSS, which will make a big difference to the speed and simulation time (there's absolutely no benefit in treating them separately).

Perhaps you could post the analysis statements from your input.scs too. That could pinpoint any mistakes which would lead to excessive memory consumption.

You could also switch to HB though, as Panchoo Hideboo suggests. In fact if you use the newer "hb" analysis (the algorithm is the same, but the interface to it is a little different) you can directly enter the frequencies of the tones on the GUI, rather than them being looked up from the sources.

Regards,

Andrew.
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