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[Gnucap-devel] gnucap vs. spice benchmark
From: |
Al Davis |
Subject: |
[Gnucap-devel] gnucap vs. spice benchmark |
Date: |
Thu, 25 Jul 2002 00:19:40 -0600 |
I just did some timing, and I think earned some bragging
rights.
The circuit is a large linear circuit, mostly RC with lots of
controlled sources, essentially an op-amp circuit with a simple
vcvs model of the op-amp. There is a lot of repetition. It is
an expansion of the "eq" circuits in the gnucap test files. It
has 36865 nodes, after expansion. The benchmark is a transient
analysis.
Spice 3f5 took 363 seconds.
Gnucap took 66.6 seconds with the default settings, which are
stricter than Spice.
Relaxing the specs ...
eliminating the check iteration (one more just in case), now
46.4 seconds. (still stricter than Spice)
from there, relaxing step control, so it does the same number
of time steps as Spice, now 28.1 seconds. I believe this is
the closest to equivalent accuracy to Spice, better than 10x
faster.
further relaxing the step control, allowing it to completely
free-run, now 17.5 seconds. The answers still look good.
Now, going the other way ....
No bypass, no incmode, etc .... This is essentially Spice
algorithms, but Gnucap's normal tighter checks, including the
extra check iteration, now 294 seconds. Still faster than
Spice, no optimization, more accurate.
No bypass, no incmode, etc ... with no check iteration, relaxed
time stepping, now 111 seconds. This is as close to the Spice
algorithms, and Spice accuracy checks as I can make it.
The "check iteration" is another pass done for accuracy
checking after a step has been conditionally accepted. Spice
doesn't do this. Its purpose is to catch false convergence.
Since this circuit is linear, I suppose it could get by without
any convergence checking, possibly saving one more iteration.
Just figured I would pass that on.
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