Flattening hierarchy option before extraction

[DiarmuidSLICE]

It is not reccomended to use hierarchical RCX extraction when using the magic extraction engine. As per Tim Edwards guidance:

"This is mainly why I currently don't suggest using hierarchical RCX extraction, because I don't really know how it determines the points and directions of current flow between cells in the hierarchy.
For a flattened cell, magic will use any specified port as the point of origin for the current. All named ports will retain the port name, so if there are multiple "VDD" ports, say, then they will be effectively tied together with zero ohms."

For this reason, user should run the "flatten" command before doing extraction.

Syntax is "flatten <name_of_new_cell>".

However, this switch is currently not supported in kpex (see attached).

I would see this as high priority to avoid current flow ambiguity in extracted netlists. For example:

In a commercial tool, if I place pin "VDD" in the top right corner of the layout, this means the extraction netlist will result in current being injected at this point (no ambiguity). If I place multiple "VDD" pins across the top level, current will be injected at these multiple points, hence replicating a power grid. We need to be certain this behavior is replicated in kpex which is achieved by flattening the hierarchy first before running the extraction.

Thanks,

Diarmuid