@User, the test_comparator example does run on my system, however the montecarlo does not work anymore, i just get 20 nominal simulations, all identical. I don't know if something is changed in the pdk or in ngspice or both. The example was supposed to generate a sample of the vcc voltage (in addition to variations of all mos thresholds) for each run, however i don't see any variations. This was a self made hack to do MC on sky130. I think there is now a standard way to do MC runs with sky130, however i am not (yet) familiar with the right procedure.