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Re: gEDA-user: Soft and Hard symbols

> Dietmar Schmunkamp wrote:
> > Start a design with gschem --> simulate it --> get it thru
> > pcb --> extract physical paramaters from the layout -->
> > OPTIMIZE* --> feedback to gschem --> restart the loop.

On Friday 07 January 2011, Kai-Martin Knaak wrote:
> Unfortunately, at the current state of geda and friends the
> simulate  step is a weak spot. Not so much because of
> weaknesses in the simulation algorithm. With gnucap and
> ngspice there are two very capable engines. It is the
> absence of readily available models and almost no GUI
> support that blocks the road.

Actually, not at all because of weaknesses in the simulation 

NGspice has essentially the same algorithms as LTspice.  When I 
benchmarked them (a few years ago) they were indistinguishable, 
which makes sense because they are both derivatives of Spice-3 
from Berkeley, which also is mostly indistinguishable in a 
performance sense.

Gnucap has more advanced algorithms.  My benchmarks show much 
faster performance on large circuits and more robust time step 
control.  Ironically, "switch mode power supply" is a type of 
circuit that works fine on gnucap, but I got identical 
believable bad results on both NG and LT spice, due to step 
control problems.

There is a real problem with the interface to gEDA, and also 
with displaying the results.  Does anyone want to help fix this 

There is somewhat of a problem with models, because most models 
are written for a specific simulator and moving to another makes 
a lot of them not work.  There are several strategies for 
improving this situation, ranging from adding features to the 
simulator to porting models.

Both of these are areas where we could take the lead, but I need 
help to do that.  I can't do it alone, and can't do it if people 
are fighting it.  Does anyone want to help?

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