@Stefan Schippers I am trying to simulate a circuit in xschem wherein the some devices have nf=10. I have used .option wnflag=1 and aslo have the command set ngbehavior=hsa in the .spiceinit file. Still ngspice shows the error could not find valid modelname. Here is the spice file that I am using

I believe W is the total width of the combined device. So if you have 10 fingers each with a width of 1um, nf=10 and W=10um. If you have one device with a width of 10um, nf=1 W=10um. nf is just used in the ad/as pd/ps calculations and not in LVS.

@Pranav Lulu as @Mitch Bailey said , for these transistors the W attribute is the total width. If you have W=1 and nf=10 the transistorr is made up of 10 fingers each with W=0.1. This value is too small. Either increase W or reduce nf. That said, xschem has

*_nf.sym

symbols where the value of W given is the single finger length, so the actual W of the transistor will be calculated as

Wtot = W * nf

@Mitch Bailey @Stefan Schippers Got it!!