Arpad,
Your assessment is correct. The sum total of this discussion is that the
only Redriver flows that we should all be able to agree on is the
statistical flow when all models have Init_Returns_Impulse=True, and a time
domain flow when all models have GetWave_Exists=True as defined in BIRD166.
We should also be able to agree that:
1. If any model has Init_Returns_Impulse=False, the EDA tool must create a
proxy AMI_Init function for that model to get statistical results.
2. If any model has GetWave_Exists=False then the EDA tool must create a
proxy AMI_GetWave function in order to get time domain results using the
other AMI_GetWave results of those models in the channel that have
GetWave_Exists=True.
3. The implementation of either proxy AMI_Init or proxy AMI_GetWave
functions can be problematic.
I would be satisfied if the Open Forum passed a resolution agreeing to the
above statement, and just leave BIRD 166 in purgatory, and not include it in
IBIS 7.0.
Walter
From: ibis-macro-bounce@xxxxxxxxxxxxx
[mailto:ibis-macro-bounce@xxxxxxxxxxxxx] On Behalf Of Muranyi, Arpad
Sent: Monday, June 05, 2017 9:21 PM
To: ibis-macro@xxxxxxxxxxxxx
Subject: [ibis-macro] Comments on BIRD166.3 and last week's ATM discussion
Hello Everyone,
I decided to write this email to the ATM reflector, so that Walter can also
respond
(since he will not be able to attend our meeting tomorrow).
This is based on the latest posted version of BIRD166 is draft 5 for
BIRD166.3:
http://ibis.org/macromodel_wip/archive/20170523/walterkatz/BIRD%20166.3%20Resolving%20problems%20with%20Redriver%20Init%20Flow%20draft%205/bird166.3_draft5.docx
The main comment I have is about step 8b, which could be summarized as
follows:
If any of the GetWave functions are missing, the TD flow relies entirely on
the Init
functions. But this will only work if the Init_Returns_Impulse
parameter=true for
every single Init function. While the spec does require that
Init_Returns_Impulse
must be true for a model in which GetWave_Extists=false, there is no
requirement
or guarantee that any other model will also have Init_Returns_Impulse set
to true.
(This statement is actually true even for a regular single channel
simulation). For
this reason, the rule in 8b is not guaranteed to work, unless every one of
the models
has GetWave_Exists=false. But then we are back to an “Init_only flow”
executed in
TD simulations.
With that, I wonder if having 8b in the spec helps to solve anything...
Having said that, if we decided to remove 8b from the BIRD, the only
remaining question
seems to be whether we should go with the idea of “only document the three
cases”
(Init only, GetWave only and Dual models) and say that do all other
combinations “at your
own risk”. If we all agree with that, we could be done. (But this is a
mild way of saying
that we really don’t support any other cases). Otherwise the only way I see
out of this
situation is to do something along the lines of Fangyi’s proposal (or its
variants, i.e.
execute Init multiple times, etc…) as the solution.
Comments, questions, suggestions are welcome…
Thanks,
Arpad
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