do not compute a whole I-V characterstic by default
Most introductory users would probably be well served by just seeing the PN junction in equilibrium. The whole I-V an C-V curve is very interesting, but maybe most users do not need that and users who do, could just turn the option on? Without the whole I-V calculation the simulation would run rather dramatically faster.
I suggest introducing 1) a new option that allows the users to turn on a whole I-V, and it is OFF by default 2) if the I-V is not computed then the sequences of outputs as a function of different biases should be avoided completely.
The danger is that people are not aware that a whole I-V can be computed.