WriteCapa is a package that explores the Core description of a layout and compute the stray capacitances of the wires from the ChipNDale associated data. Its purpose is mainly to produce an adequate input for the various time simulators and critical path finders. Two capacitances values are stored on each wire: the capacitance of this wire in its own hierachical level, and the capacitance from (and including) this wire to the lowest hierachical levels (= down to the transitor connections).

The data structures implemented are compressed bitmaps, that combines simplicity and efficiency of full bitmaps to estimate areas, and efficiency of memory allocation, as only the meaningfull pixel borders are stocked. The package is interfaced with CoreIO to allow the client to save on disk the capacitances values.

The capacitances from the wires inside the transistor are not part of the rootCapa.