I've just noticed that for larger circuits itl4=4 is prohibitive (gnucap tries to decrease timestep all the time).
What I am using in practical simulation is ether: .option method=trap dtmin=1e-16 abstol=1e-13 vntol=1e-7 chgtol=1e-15 reltol=1e-4 itl3=3 itl4=6 or: .option method=euler dtmin=1e-16 abstol=1e-13 vntol=1e-7 chgtol=1e-15 reltol=1e-4 itl3=3 itl4=10 -r. On Dec 1, 2007 5:17 PM, a r <[EMAIL PROTECTED]> wrote: > I think default settings for the time-step control are too aggressive. > > I am getting best results with the following settings: > > .option method=euler dtmin=1e-16 reltol=1e-4 itl3=3 itl4=4 > > .tran 1n 20n trace alltime > inverter_test.dat > > If I do not specify low thresholds for itl3, itl4 gnucap has a > tendency to use maximum allowed time steps (here 1n) and "jump over" > all interesting transistions. > > The test circuit is attached. Note that without setting itl3, itl4 the > results are not readable (although they might be considered > "correct"). > > If the time step is set to 0.001 (and itl3, itl4 are not set) the > output is good but the time step is effectively constant which is not > good for simulating sampled circuits. > > The question is: are the defaults sensible? _______________________________________________ Help-gnucap mailing list [email protected] http://lists.gnu.org/mailman/listinfo/help-gnucap
