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#analog-design
Title
# analog-design
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Ashok Kumar
10/15/2020, 5:15 PMHow to resolve "segmentation fault(core dumped problem)" ? as I got it as a result of my ngspice simulation.
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Pepijn de Vos
10/15/2020, 6:17 PMThis is a bug. It means the simulator accessed memory that it should not. There is no simple way to resolve it. You could try upgrading ngspice to the development version to see if it has been fixed, or report a bug.
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yrrapt
10/15/2020, 6:31 PMDid you use the '.ic' command?
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Stefan Schippers
10/15/2020, 10:17 PM@Ashok Kumar try to build the smallest circuit that reproduce the segfault, then report to ngspice on sourceforge, the developers are very responsive.
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Ashok Kumar
10/15/2020, 11:37 PM@yrrapt yes I have used .ic command.
@Stefan Schippers I'll do that, thank you.
@yrrapt i have removed the . ic command then it worked. but i need this .ic command for setting up an initial condition so is there any alternative.
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Stefan Schippers
10/16/2020, 12:02 AM@Ashok Kumar try to set the .IC at the end after the netlist
before the .end of course
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Ashok Kumar
10/16/2020, 12:05 AMok i'll do that. thank you
@Stefan Schippers no that didn't worked.
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Stefan Schippers
10/16/2020, 12:40 AMalso verify if all the nodes you set in .ic do exist
do no set .ic on nodes trat are driven by voltage sources
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Ashok Kumar
10/16/2020, 2:04 AMok
i have verified this and my node is not connected directly to a source and it is existing.
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yrrapt
10/16/2020, 6:13 AM@Ashok Kumar I think there is a bug with the IC command. A couple of people of have come across it here. Even if the command is used incorrectly the program shouldn't segfault so somethings wrong.
I would recommend reporting the bug with a short example netlist to the developers and see if they can have a look
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Ashok Kumar
10/16/2020, 6:39 AM@yrrapt So,I need to check whether this segfault is there or not , using a small netlist with .ic and if it is there, I need to report a bug right.
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yrrapt
10/16/2020, 6:43 AMYeah, it's really helpful for the developers if you can make an example that's as small as possible that shows the unexpected behaviour. That way they can check it out quickly - and you're more likely to get the bug fixed.
I think the ngspice folks hang out on their source forge mailing list but I haven't used it myself
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Ashok Kumar
10/16/2020, 7:27 AMOk I'll do that.
@yrrapt I just simulated the same with ngspice-32 on my windows OS and it worked.
Whereas in Ubuntu ngspice-27 it's showing this segmentation fault
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Riking28
10/17/2020, 11:14 AMYeah, that's how this kind of thing behaves
If you want to help find the bug, take a copy of your whole design, and start deleting chunks out of it. If it makes the error go away, go back and delete something else
Repeat until you can't delete anything, then send that to the developers
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Stefan Schippers
10/17/2020, 5:22 PMyou can build ngspice-32 on ubuntu, this is probably the first thing the developers will tell you. Installing ngspice from source files and compiling to get the executable is not difficult.
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Ashok Kumar
10/17/2020, 5:31 PMYeah I'll do that