Re: gEDA-user: Using .global statements in GNUcap and mult

[Yamazaki R2 <yamazakir2@xxxxxxxxx>]

On Fri, Mar 6, 2009 at 6:09 PM, Yamazaki R2 <yamazakir2@xxxxxxxxx> wrote:
>> Message: 8
>> Date: Fri, 6 Mar 2009 21:39:03 +0000
>> From: r <nbs.public@xxxxxxxxx>
>> Subject: Re: gEDA-user: Using .global statements in GNUcap and mult
>>        transistors
>> To: gEDA user mailing list <geda-user@xxxxxxxxxxxxxx>
>> Message-ID:
>>        <5b9d31e90903061339u25098f5ava9905d1d307b383c@xxxxxxxxxxxxxx>
>> Content-Type: text/plain; charset=ISO-8859-1
>>
>> On Thu, Mar 5, 2009 at 2:23 AM, al davis <ad151@xxxxxxxxxxxxxxxx> wrote:
>>>
>>>> >
>>>> > The Gnucap behavior is consistent with Hspice and Spectre.
>>>> > ?At least that is what I have been told. ?I don't have
>>>> > access to them to check it out.
>>>>
>>>> That's incorrect. Both Spectre and Hspice treat devices with
>>>> m>1 as single entities.
>>>
>>> ok .... ?maybe you can help solve this.
>>
>> Well, I'm not sure. I don't know how it is implemented in these
>> simulators. I guess these guys have simply modified the models (they
>> have modified quite a few other things there so I guess they wouldn't
>> have minded adding "m" parameter as well).
>>
>>> Also consider that there are a bunch of parameters that can be
>>> probed. ?Some multiply, some divide, some are not changed.
>>> There is no indication in the code of which is which. ?There
>>> could be hundreds of parameters that could be probed. ?All that
>>> is known is a name and the type (real, int, string, ....) that
>>> it returns. ?There is no notion of across, through, or anything
>>> that helps the decision of how to scale.
>>
>> Perhaps it could be done at the time of stamping the matrix - by
>> multiplying all gm's by a factor of "m". Then all the probes would
>> "just work". I have no idea how it could be done technically, though.
>>
>> BTW, some simulators preprocess the netlist and reduce parallel
>> devices into a single device with an "m" parameter set. This gives a
>> huge performance boost in extracted sims.
>>
>> -r.
>
 **WOW** I'm an idiot I can't believe I didn't think of that! I'll just
 add a wrapper script for my simulations to preprocess the netlist and
 merge the transistors with the m parameter. That should be a quick and
 easy solution until gnucap automatically does this for you. If anybody
 is interested I can post the script on the mailing list for everybody
 else to use. I'll probably just use perl for regex capability.


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