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ADS<->LIBRA ser IV simulation time differenc

Question asked by ERKKIN on Feb 8, 2005
Latest reply on Feb 9, 2005 by ERKKIN

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Hi,

I was quite disappointed when comparing optimization times of my 7-port design with ADS 2004A and ser IV LIBRA ver. 6.6.
Designs are the same in both cases, having 601 points, 18 optimization goals, 25 rounds (gradient opt.) and only 6 optimization variables (just to compare running times). ADS execution time 742.23 seconds versus 242 seconds with ser IV. So the difference is enormous. Can you give me a good explanation ? Why does it take os long time to optimize the same circuit with ADS ?

Erkki

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wrivas Feb 9, 2005 12:10 AM
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One possibility is that in ADS you have the UpdateDataset feature turned on in the Optimization controller, by having UpdateDataset=YES, which by the way is the default setting. This feature is nice because you can see the data display updating as the optimization is running. However the program has to do extra steps to do that and this will consume CPU time. I ran an optimization and by turning the UpdateDataset off the simulation time went from 103 sec to 91 sec. Now that still does not account for the difference between the two tools.

Another possibility is the tolerance. Are you running with the same tolerance in both softwares? In ADS by default all the tolerance are set to a strict setting. This means that:
V_RelTol=1e-6
V_AbsTol=1e-6 V
I_RelTol=1e-6
I_AbsTol=1e-12 A

I do not recall what these use to be in Series IV.
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ERKKIN Feb 9, 2005 4:24 PM
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Hi,

Ser IV is updating the display during the optimization. I do not know what are the error tolerances in it.

I made another test with ADS and ser IV:
7-port circuit, 601 points sweep with no optimization:
running times ADS 8.68 s and ser IV 2.7 s. Still the difference is too much. Have to look the same circuit with MWO (Microwave Office). Why is the ADS code so slow?

Erkki
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ADS<->LIBRA ser IV simulation time differenc

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