@User: This looks like the error when you don't apply Stefan Schipper's patch to the sky130_fd_pr library to move the "nf" parameter up in front of the other parameters that use it as a reference.

Thanks @Tim Edwards for to-the-point direction. I corrected the "nf" parameter position in model library files and the error went away.

@shbo : If you use the open_pdks installation, then the patch is applied automatically when generating the model libraries.

@Tim Edwards, I think my open_pdks installation is outdated. I will update it soon.

True, that was a relatively recent addition.

In case it is helpful, just wanted to add I installed with the open_pdks route yesterday and had the same issue. The sky130_fd_pr_ngspice directory was there, but the patch was not applied in it. If I download the patch and run it manually, then I can simulate. Finding this discussion was very helpful!

@iain: Thanks for the feedback. What version of open_pdks were you using? I posted an upate to opencircuitdesign.com yesterday that affects the patch file application, so I want to make sure that I didn't mess up something (it worked fine on my end, but that's often not the full story).

@Tim Edwards The version I have is 1.0.148, and I see the most up to date is now 1.0.150, so perhaps in the latest version it is OK.