Re: gEDA-user: Hierarchy vs spice-sdb

[Al Davis <ad82@xxxxxxxxxxxxxxxx>]

On Thursday 17 November 2005 03:42 pm, John Doty wrote:
> Apparently, gnetlist runs down the sources and expands them
> before the spice-sdb backend has a chance to look at the
> associated symbols. The result is chaos, with top level cards
> inserted into subcircuit definitions willy-nilly.
>
> I see two different approaches here:
>
> 1. gnetlist does the netlist expansion, flattening the
> hierarchy.
>
> 2. gnetlist preserves hierarchy, allowing SPICE to do the
> expansion (the spice-sdb approach).

It is better to preserve the hierarchy and let the simulator 
deal with it.  When you flatten you remove important 
information that the simulator can use to enhance performance.

> One advantage of having gnetlist do the expansion is that you
> get nice netnames like X1/OUT (ngspice isn't so friendly).
> Also, for board design, a flat netlist is required (at least
> by the PCB designer I usually deal with). The "source"
> mechanism is also nice, allowing the designer to avoid the
> difficulties wired-in pathnames cause.

If your target application requires flat netlists, make a 
separate utility to flatten it.