I believe a good feature to include in ngspice would be a command that allows model substitution
through the command line. This is useful when running a lot of simulations where you only change
which models are used. This way you would not have to text edit the netlist at all. For example, if
you have several components/models you want to compare which are pin-pin compatible (say
similar products from different manufacturers). Then you can make several input files which call
the commands you use when running your simulation, one file per component you wish to simulate.
This is much easier than text editing a netlist file everytime you want to try a different
The command should search through the entire netlist file, replacing one model filename with
another. Basically it can be described as a search and replace, which can be run through the
ngspice command line. An example syntax is like this:
replacemod <original> with <new>
If <orginal> is not found within the netlist file, ngspice should display a warning saying <original>
was not found. This would let the user know that there is a mistake.
Please inform me if you believe this is a feasible addition for the next release. If you have any
further questions about this feature, or need clarification about something, feel free to ask. Thank
you for your time!