Re: gEDA-user: Google SoC : Potential Candidate seeking Info

[John Doty <jpd@xxxxxxxxx>]

On Feb 17, 2009, at 2:12 AM, al davis wrote:

> Another interesting type of analysis that Spice doesn't have is
> a semi-symbolic analysis, where the result is a transfer
> function, in S, that has some values carried through as
> symbols.  I would have to help you a lot, but it would be a
> real accomplishment, and I think I know of a few places where
> you could get a paper out of it. .. at least a conference
> paper, maybe two, maybe even a journal paper.

There's an existing netlister that I wrote, distributed with gEDA,  
that produces Mathematica equations for this purpose. I think this  
kind of analysis really needs a computer algebra system behind it to  
do the manipulations. See:

http://www.noqsi.com/images/gEDAmath.nb.pdf

Now the trouble is that Mathematica is rather pricey proprietary  
software, so it would be nice to have a similar implementation for a  
free CAS. Back at the last code sprint, my math grad student son and  
I sat at Ales' table and attempted to port this approach to Sage, and  
we spent some more time the next day. We concluded that Sage isn't  
quite ready to support this: it seemed like we were rather sloppily  
extending Sage (whose internals we don't understand very well) rather  
than focusing on the problem at hand.

There may be another path that will get better results, but I doubt  
it makes sense to implement a computer algebra system inside gnucap.  
Personally, I'd rather see the gnucap effort put into noise analysis:  
that just might persuade me to abandon ngspice.

John Doty              Noqsi Aerospace, Ltd.
http://www.noqsi.com/
jpd@xxxxxxxxx




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