The input records can be ordered as indicated in the table of contents. There are a few restrictions on the placement of input records.
The .TITLE, .INC, .PAGE, .OPT, .AC, .DC, .VARY, .TR, .IC, .DELAY, .MAKECKT, .TEMP, .MODEL, .CALC, .STDR, .STDC, .STDL, .SENSA, .SENSR, .MSENS, .WSENS, .SSENS, .NOISE, .FSCALE, .ZSCALE, .PLOT, .ZDLY, and the .CKT to .END section must preceed the first .GO record to be effective during the analysis of the circuit.
As previously discussed, there can be only comment, network command, element description, .PAR, and .INC records between the .CKT and .END records and all element description records must be between the .CKT and .END records. The .INC records used in the .CKT - .END section must specify files which contain only comment, network command, .PAR, .INC, and element description records. The .ALTEL, .ALTGO and .GO records should come after the .CKT - .END section and before the .NEXT or .STOP records.
It is suggested that sources (V and I elements) be placed at the beginning of the CKT section.