Re: [Gnucap-devel] two event queue questions

[al davis]

On Thursday 07 June 2012, Felix Salfelder wrote:
> /* finish_building_evalq
>  * This function scans the circuit to queue for evaluation
> anything  * that is relevant that the devices missed
> themselves. * For now, it scans the whole circuit, but this
> will change. * This is slow, but the result is still faster
> than not having a queue. * The plan is .. every node knows
> whether it needs eval or not, and * only those nodes needing
> eval will be scanned.
>  * Its purpose is to catch nodes that wake up after being
> dormant */.
> 
> what's the state of this more sophisticated queuing? and how
> would it affect digital device simulation? is there anything
> worth considering?

That's really all that was done.  It would be great to finish 
the job.

At the time was that I was looking for a research faculty 
position, and thought of this as one of my seeds for further 
research.  As it turns out, I never got that kind of faculty 
position, and schools I ended up at as faculty were not 
interested in this kind of research, so it didn't get developed.

For a reference, see Karem Sakallah's Ph.D. thesis (from 
Carnagie-Mellon) on "SAMSON" a mixed mode simulator from the 
1980's.  This thesis contains lots of backround information, and 
should be considered to be a predecessor to gnucap.  I don't 
have it handy now, and I am trying to get things together for a 
conference exhibit next week.  If you ask again in a few weeks I 
should be able to dig up more info.

SAMSON code was never published, but a bunch of papers were.

It brings up some political issues.  Back then, Berkeley 
released all of their code, essentially placing it in the public 
domain.  CMU kept the code private, hoping to capitalize on it 
through industry connections.  The quality and quantity of the 
work coming out of both are comparable.  Now, when you think of 
university EDA research, university research in simulation, 
which do you think of first?