Re: [Ngspice-devel] Introduction and adms questions

[Ivan R. N. <iva...@ad...>]

Hi Laurent,

Thank you for your reply.
>=20
> adms creates (should) create guesstopology() as follows:
> 1-all bias-dependent assignments are removed
> 2-all bias-dependent assignments are kept
> 3-contribs are replaced by some C code that set some flags
> to nodes
>=20
> For instance:
> if(rd>0)
>   I(br)<+V(br)/rd;
> else
>   V(br)<+0.0;
> becomes in guesstolopogy() (it is just pseudo code to
> explain the intent):
> if(rd>0)
>   br.jacobian.required=3D1;
> else
>   br.pnode.ptr=3Dbr.nnode.ptr; HERE NODES ARE COLLAPSED
> After guesstolopogy() setup() allocates the jacobian
> according to the values
> of the flags 'required'.
>=20
> It is possible that something goes wrong with the creation
> of
> guesstopology() by adms.
> Can you send me the file?
>=20
> Can you make sure that rd and rs are >0?

That might have been a weakness with the first model.  I added a check for =
rd=3D0 and rs=3D0 like you suggested, and it did indeed do the conditional =
node collapsing.  Cool!  However, the problem seems to lie elsewhere, since=
 the generated c-code still segfaults.  I'm attaching code with the rd/rs m=
odification together with the generated c-code for guesstopology().

>=20
> You can run your simulation is debug mode (tons of info are
> printed but
> they help to see what happen.) There is a test:
> if(getenv("ngspice_debug"))
> ...
>=20
> Try to set the value of the shell variable 'ngspice_debug'
> to 1.

This gave no further info.  The segfault happens before any debug output is=
 produced.

Best regards
Ivan