ACS with the "free" Borland compiler
> -----Original Message-----
> From: Al Davis [mailto:aldavis@ieee.org]
> None of these should be hard to do. Remember, my emphasis has been
> research, as an attempt for someone who is not affiliated with any
> kind or research institution to do some research. As such, many
> features that are important to a user, but boring from a research
> perspective, have slid.
Absolutely, I can appreciate that you're doing research into
circuit simulation, not circuit design.
> All 4 of these are good ones for someone other than me to do. They
> are simple conceptually, yet require the knowledge of ACS internals.
> It is a good learning experience. You get to study a non-spice
> mixed-mode simulator, object-oriented programming, C++, .....
So they're good starting points for we "ngspicers" to start
playing with. I certainly intend to have a deeper look into
ACS, although I'm currently interested in writing a decent
win32 post-processor for viewing simulation results, so
progress will not be blisteringly fast.
> The hardest part is untangling the spaghetti code in the Spice model.
> This, too, is a good learning experience for someone who wants to
> really understand modeling in simulators. This untangling needs to
> be done for Spice, too, if you want to move forward. The monolithic
> models are a major obstacle to moving forward on the algorithms.
I think I understand the DC bit of the bipolar model, the
problem is the charge storage and excess phase stuff. All
interesting stuff, but so much to do, so little time ;-)
> ACS does support initial conditions on capacitors and inductors.
Really ! Then that probably gets round a lot of cases,
i.e. just stick a 1fF cap with an IC parameter across
the important nodes.
> Again, should be easy to do. I am not convinced that it should be
> binary. We really need a good postprocessor. Still, you will need
> to select, but you could select a bunch of probes by wildcard.
With the amount of data I like to generate (start-up of switched-
mode power supplies) I think that single precision binary and
a file system that can handle >4GB files is the only solution.
> Spice needs to be able to probe stuff other than node voltages!
Er, it does, doesn't it ? Or am I misunderstanding you ?
Actually, maybe you're right. I put in a hack to my version
of spice, which is now in ngspice, which stores the terminal
currents of all devices with internal nodes. This usually
means all diodes, bjts and mosfets, but we need to fix it
so that it's no longer a hack, and so that it stores all
device currents. This happens if you say .save alli (.save all
still only saves node voltages). Spice can save lots of other
parameters as well, but you can't ask for them with wild
cards or anything.
> What do you do when different nodes in the same circuit are
> calculated at different times?
All part of the plan ;-) You're previous comments on this
kind of problem got me thinking. I don't know if I ever
emailed my next rawfile format which tried to take this
into account. If I didn't, then maybe I should, 'cos I
can't remember exactly what I had in mind !
Cheers,
Alan
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