ADEXL Montecarlo, only netlisting

Hi Pierre,

The reason why " /MonteCarlo.0/11/Test:sim_wr:1/   and /MonteCarlo.0/12/Test:sim_wr:1/" have different waveforms, is because spectre generated both of them from a single run of spectre. The netlist is shown per monte carlo point, but it ran several of them together (because numruns was greater than 1). So if max jobs=20, nb runs=100, spectre will do a simulation with firstrun=1 numruns=5, then firstrun=6, numruns=5 etc. If you look at the netlists for runs 1 through 5, they all have the same netlist - but the results were generated by the same invocation of spectre - it ran with the sweep inside the simulator - it wrote out the results for point 1,2,3,4,5 from the single netlist it was given.

If it is failing (to converge) then that is not necessarily a circuit issue, but more a simulation issue (it might be due to the models, or a need to give a better starting point for the simulator). Anyway, if it converges in the first run (in sets of 5, rather than individual runs), I would be fairly confident in the results.

If however you get significantly different results, and it's a spec failure you're getting, it's possible that your circuit has more than one stable operating point - circuit simulators will DC converge to one solution - but which one you'll get if there is more than one depends on the starting conditions.

Kind Regards,

Andrew.

Hi Pierre,

The reason why " /MonteCarlo.0/11/Test:sim_wr:1/   and /MonteCarlo.0/12/Test:sim_wr:1/" have different waveforms, is because spectre generated both of them from a single run of spectre. The netlist is shown per monte carlo point, but it ran several of them together (because numruns was greater than 1). So if max jobs=20, nb runs=100, spectre will do a simulation with firstrun=1 numruns=5, then firstrun=6, numruns=5 etc. If you look at the netlists for runs 1 through 5, they all have the same netlist - but the results were generated by the same invocation of spectre - it ran with the sweep inside the simulator - it wrote out the results for point 1,2,3,4,5 from the single netlist it was given.

If it is failing (to converge) then that is not necessarily a circuit issue, but more a simulation issue (it might be due to the models, or a need to give a better starting point for the simulator). Anyway, if it converges in the first run (in sets of 5, rather than individual runs), I would be fairly confident in the results.

If however you get significantly different results, and it's a spec failure you're getting, it's possible that your circuit has more than one stable operating point - circuit simulators will DC converge to one solution - but which one you'll get if there is more than one depends on the starting conditions.

Kind Regards,

Andrew.