RE: [ng-spice-devel] NEW CVS Commit [URGENT]


To "'ng-spice-devel@ieee.ing.uniroma1.it'" <ng-spice-devel@ieee.ing.uniroma1.it>
From "Gillespie, Alan" <Alan.Gillespie@analog.com>
Date Fri, 20 Apr 2001 10:40:53 +0100
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> New function: CKTncDump.

I couldn't remember what that was, but I checked it out, and it
prints out the last iteration, and the one before that, for use
in the case where spice doesn't converge. It gives you a clue
where the problem nodes are. It's not always very useful, though.

> Forgotten code: niiter.c was not patched with Alan's additions.

That code was for the "node damping" option. It's experimental,
and I don't think it works properly. It's supposed to limit the
iteration to iteration change in node voltages and voltage source/
inductor currents. I've only seen it help convergance on a couple
of cases, and mostly it makes things worse. I think it's 'cos I'm
not damping the ckt state variables stored elsewhere, so it needs
more work.

I spotted the technique in the APLAC documentation, if anyone's
interested. I think Al's doing something similar in ACS.

Cheers,

Alan

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