This is an ngspice question more than an xschem question. I apologise in advance if it's more appropriate to post on ngspice-users mailing list but I thought I'd have a go here since xschem and ngspice have a fairly close relationship. I'm trying to loop over some tran simulations, each time measuring a frequency and storing away a couple of vectors to eventually plot in the xschem UI. I've attached my spice script (without full netlist) containing the control section. I think that I've followed the advice in the control structure tutorial correctly but executing the script yields "When creating a new vector, it cannot be indexed.", presumably due to the "let" prefix on line "let vecvctl[index] = varvctl" ... I suspect something to do with the dynamic context of where the vectors are being created (the const plot for the initial creation?). Any ideas of how to debug this?

This is tricky but doable. I have prepared an example where I want a graph showing delay vs transistor width of a simple circuit where a pmos charges a capacitor. In the image the upper graph shows the delay of 'b' signal reaching 2.5V at various transistor widths (2, 3, 4, ...)

Thanks for all the tips. I'm nearly there now. I notice that part of the solution is to override the sim_type=dc in the xschem plot which I've done but I still see 'time' in the bottom left corner of the graph. I've attached updated script and xschem graph directives. I'm still not sure what's wrong as I can see what I think are the correct vectors being produced in my ngspice plot and can plot from ngspice - the problem must be with my xschem graph... Any ideas?

set the curplotname to "`DC transfer characteristic`". Xschem uses that information to get the right section of data. so you can simply set graph

sim_type

to "`dc`" . (

dc

is a short abbreviation, together with

tran

,

ac

,

noise

,

dc

,

op

that xschem maps to "DC transfer characteristic", "Transient analysis" and so on). Otherwise tou can set curplotname to "`foo`" and set

sim_type

to

foo

.

I see. Got it. Thanks very much.