#193 Error in saved .sch files leads to incorrect cartesian plot

[Mr Fish]

It seems that wrong .sch files are created, which leads to wrong cartesian plots. When changing one resitor value in qucs the file (sometimes?) is saved different and cannot be plotted anymore. When I change the same value in .sch file directly then it is plotted correctly.
Comparison reveals that there is a difference in the two .sch files although I only changed a resitor value.

[Claudio Girardi]

thanks for the bug report. Indeed for the second schematic the results are incorrect; for some reason the simulator assumes some wrong initial voltages. It might be related to the order the initial conditions are evaluated.
The .sch file seem correct in both cases; I think that what is actually happens is that the different order of the components causes the simulator to use a different starting point for computing the result (which should of course actually lead to the same results anyway but it doesn't).

[Mr Fish]

Hi Claudio,
Thanks for your explantion. Can you think of a workaround?

Cheers,
Thomas

[Claudio Girardi]

uhm, no; I'll need some time to dig into the simulator code and try to understand where exactly the problem comes from.

[Guilherme]

I don't know how the NodeSet gets applied, but I aways found suspicious that the default initial voltage of a capacitor is se to V="" (empty) instead of V="0.0". If you set the initial voltage on the capacitor, the falty circuit seems to work.

[Mr Fish]

Interesting. I'll give it a try.

On 11/27/2016 01:57 PM, Guilherme wrote:

I don't know how the NodeSet gets applied, but I aways found
suspicious that the default initial voltage of a capacitor is se to
V="" (empty) instead of V="0.0". If you set the initial voltage on the
capacitor, the falty circuit seems to work.

---

[bugs:#193] https://sourceforge.net/p/qucs/bugs/193/ Error in saved
.sch files leads to incorrect cartesian plot

Status: open
Group: 0.0.19
Created: Mon Aug 22, 2016 07:40 PM UTC by Mr Fish
Last Updated: Mon Aug 22, 2016 08:45 PM UTC
Owner: nobody
Attachments:

• 1.sch https://sourceforge.net/p/qucs/bugs/193/attachment/1.sch
  (1.3 kB; application/octet-stream)
• 1_simulation_error_cartesian.sch
  https://sourceforge.net/p/qucs/bugs/193/attachment/1_simulation_error_cartesian.sch
  (1.3 kB; application/octet-stream)

It seems that wrong .sch files are created, which leads to wrong
cartesian plots. When changing one resitor value in qucs the file
(sometimes?) is saved different and cannot be plotted anymore. When I
change the same value in .sch file directly then it is plotted correctly.
Comparison reveals that there is a difference in the two .sch files
although I only changed a resitor value.

---

Sent from sourceforge.net because you indicated interest in
https://sourceforge.net/p/qucs/bugs/193/

To unsubscribe from further messages, please visit
https://sourceforge.net/auth/subscriptions/