Programmable integrated circuits use special files to physical change an integrated circuit in order to get the correct function. The structure is specified in the EDIF langauge. This change is performed by programmer instruments.
For custom integrated circuits all wiring and placement must be designed. The resulting pattern is described in the language GDSII.
Hspice is a design environment for physical circuit simulation.
Ledit äis a synthesis tool for automatic or manual placement and wiring