@Laxman Chinnannavar this kind of switch was for HSPICE, i believe. Use

switch_ngspice.sym

. You need to provide a model for it, something like:

.MODEL swmod SW(VT=0.5 VH=0.01 RON=0.01 ROFF=10000000)

For the details please see the ngspice user manual, section 3.3.15

Ok got it. Thanks