Re: [Gnucap-devel] [Help-gnucap] Bizarre behaviour -- possibly a bug.

[Felix Salfelder]

On Sun, May 26, 2013 at 04:05:16AM -0400, al davis wrote:
> Spice avoids the problem by not printing anything for time=0
> when you do UIC.  Gnucap plainly shows that UIC is screwed up,
> as it implements bug-for-bug compatibility.

spice-compatibility is fine, but spice sucks. how about extending the dc
and tran commands a bit? in gnucap-uf, i have implemented an "uic"              
                                                                                
       
switch for dc and a "cont" switch for tran. so this works:                      
                                                                                
       

spice
V1 m1 0 3
R1 m1 m2 50
C3 m2 0 4u ic=0.5

*     V1   __R3  C3
*  o---O--[__]--||---o
*  |                 |
*  V                 V

.print dc v(nodes)
.print TRAN  v(nodes) conv(C3)

* change C3 into a voltage source and compute OP
.dc uic
* do a transient starting from that OP
.TRAN 0 200u 10u cont
.end

if you like, you can port this to upstream. lets see if it can be done          
                                                                                
       
without breaking other things (i'm pretty sure). the changes to
s_{dc,tran} can start as plugins in opt. changes to d_cap and backend
need more thought...

regards
felix