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hello <@U01819B63HP>, a question in you demo of “test_sweep_mos_w” what are the remzerovec lines for?

Hello! It looks like this is something related to the SPICE simulation. Some related thread on ngspice's mailing list:
<https://sourceforge.net/p/ngspice/patches/29/>

So it seems like a workaround to limitation of some spice implementation to cleanup the file before saving it:
<https://sourceforge.net/p/ngspice/bugs/596/#8a1e>

To avoid errors like
```[...] is not available or has zero length```

Hello, <@U03CSQTGFM2>, as explained the remzerovec is a workaround to some ngspice problem when some electrical nodes don't generate any data. These 'zero' vectors cause an error when writing the raw file and as a result nothing is written. The remzerovec command removes such vectors (often related to body currents of mos transistor) so following write command does not run into errors.
In my opinion this is a flaw in ngspice and should be resolved in a more elegant way. I now *always* put the remzerovec command before the write line, to avoid these irritating errors.