Re: Re: FLOW disciplines and KCL

Sorry I didn't get to finish that message.. 
the point I was trying to make was that implicit
equations and "signal-flow" disciplines are separate
features.  

You don't need to use a signal-flow discipline to use
an implicit equation. 
You use signal flow where you don't NEED the overhead
of a flow with the potential or a potential with the
flow.

Jonathan

--- Jonathan David <jb_david@yahoo.com> wrote:

> No, you are confusing implicit equations which
> support
> having the simulator solve for the solution with
> signal-flow which lets you use
> --- peterl@xpedion.com <peterl@xpedion.com> wrote:
> > I think the original idea behind signal flow is to
> make it an "unknown" 
> > in a differential algebraic equation so it can be
> solved as part of the 
> > system and then used.  As I originally stated,
> something like
> > "V(n1) <+ 2*V(n1) +1;" is definitally allowed.
> > We can then use the simulator as a more general
> solver.
> > NOTE: A signal flow node should be the similar to
> a
> free quantity in 
> > VHDL-AMS.
> > 
> > Peter Liebmann
> > 
> > Marq Kole wrote:
> > > 
> > > Jonathan,
> > > 
> > > A resulting limitation for the signal flow
> disciplines connecting to a 
> > > conservative discipline would be that a signal
> flow node can have only 
> > > one conservative instance connected to it, and
> that all signal-flow 
> > > instances need to have the same port direction,
> i.e. all in or all out.
> > > 
> > > Should an inout port direction not be allowed
> for
> signal flow models: it 
> > > has to be either in or out. I can image a model
> where a signal-flow port 
> > > is either read or driven, dependent on a
> parameter
> setting, but it 
> > > cannot read and drive at the same time...
> > > 
> > > Regards,
> > > Marq
> > > 
> > > 
> > > Marq Kole
> > > Competence Leader Analog Simulation, Philips
> ED&T
> > > 
> > > 
> > > Marq Kole/EHV/RESEARCH/PHILIPS wrote on
> 02-06-2006
> 16:08:32:
> > > 
> > >  > Jonathan,
> > >  >
> > >  > Your reply required some thinking before I
> could answer; I'll also
> > >  > copy the reflector as I think this is
> relevant
> to our discussions.
> > >  >
> > >  > Regards,
> > >  > Marq
> > >  >
> > >  >
> > >  > Marq Kole
> > >  > Competence Leader Analog Simulation, Philips
> ED&T
> > >  >
> > > 
> > >  > Jonathan David <jb_david@yahoo.com> wrote on
> 31-05-2006 18:41:25:
> > >  >
> > >  > > Hi Marq,
> > >  > >
> > >  > > thanks for the reply. It looks like you
> missed part of
> > >  > > my point.
> > >  > >
> > >  > > Let me ask a question;  For a potential
> nature, do you
> > >  > > expect KVL to be obeyed? I do, and I think
> you do
> > >  > > also..
> > >  > > V(B) = V(A) + V(B,A)
> > >  > > V(A,gnd) + V(B,A) + V(gnd,B) = 0;
> > > 
> > >  > This is not necessarily the KVL: in
> mathematics
> this is also known
> > >  > as associativity. If you consider 0 to be the
> mathematical ground
> > >  > i..e reference, then with V(B) = 2 and V(A) =
> 3
> you say:
> > >  >
> > >  > 2 = 3 + (2 - 3)
> > >  > (3 - 0) + (2 - 3) + (0 - 2) = 0
> > >  >  
> > >  > > therefor when I flip to the FLOW side, I
> expect KCL to
> > >  > > be obeyed.
> > >  > > KCL: Sum(I)@node = 0;
> > >  > >
> > >  > > In fact if it isn't, it wouldn't be
> possible
> to
> > >  > > connect the flow type to the flow
> connection
> of the
> > >  > > compatible conservative discipline.
> > >  > >
> > >  > > but your example doesn't show a violation.
> > >  > > Without the context (how the block is
> connected) we
> > >  > > can't talk about KCL.
> > >  > > Your example has no context.. its not
> connected up
> > >  > > with any thing else, and without the
> connection nodes,
> === Message Truncated === 
> 
>