Several code models (filesource 12.2.8, d_source 12.4.21, d_state 12.4.18) call additional files for supply of input data. A call to file="path/filename" (or input_file=, state_file=) in the .model card will start a search sequence for finding the file. path may be an absolute path. If path is omitted or is a relative path, filename is looked for according to the following search list:

1. Infile_Path/<path/filename> (Infile_Path is the path of the input file *.sp containing the netlist)
2. NGSPICE_INPUT_DIR/<path/filename> (where an additional path is set by the environmental variable)
3. <path/filename> (where the search is relative to the current directory (OS dependent))