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[Gnucap-devel] papers and progress

From: Al Davis
Subject: [Gnucap-devel] papers and progress
Date: Fri, 20 Sep 2002 09:50:09 -0600

I am getting close to making another release.  The main focus 
over the summer has been IBIS support for IBIS models.  I have 
a customer that wants it, so that pushes it up in priority.  
That part is not quite ready yet, so it won't be in it, but has 
taken a lot of time.  Here's a preview:
New features:

1. Series resistance in the diode.  It took 5 minutes to do, so 
it is embarrasing that it wasn't done before.

2. History and command line editing, using Gnu Readline.  
Thanks to Simon Hoffe for sending me the patch.

3. More parameters in the BJT model.  This gives it better 
compatibility with commercial simulators.  These parameters are 
beyond Spice 3f5.  With the model compiler, it is easy.

4. "M" parameter in diode, BJT and MOS devices.  M is the 
number of parallel devices.  Some commercial simulators have 

Changes that may or may not be improvements.

1. The definition of the transient option "UIC" has changed.  
It is now Spice compatible, which means to not attempt to do 
any solution or consistency check.  Just apply the values, 
assuming anything that isn't specified is 0.  The old behavior 
was to attempt a solution while holding the IC values.

Bug fixes:

1. voltage sync bug.  It still doesn't fix the MOS 2 convergence

2. Fix memory leak in POLY components.

3. Fix bug in Fourier that sometimes causes overrun (crash) and 
time sync errors.

4. Modelgen: fix bug in list parsing.

5. Some changes to eliminate warnings when compiling with g++ 

6. Use Euler differentiation on first step, because trap used a 
value  that cannot be known then.  Usually, this doesn't make 
much difference, but there are a few cases where the error can 
get magnified and trigger trapezoidal ringing, leading to a 
totally bogus result.  It most cases, you could hide it with 
small enough steps.  These cases should work with default 
settings now.

7. Fix bug that sometimes caused incorrect handling of initial
conditions (UIC),

8. Fix bug that caused continuing a transient analysis to give
incorrect results.

Also, I have put some files up on  .  These are some papers and 
presentations about the algorithms in gnucap, and about the 
model compiler.


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