Contributions (was Re: disallow distributed switch branches)

Marq -
In most cases, though, the distinction doesn't matter:
if you don't expect the contributions to accumulate,
then you write your model with a single contrib and
everything works fine; or you have multiple contribs
of complicated expressions, and for efficienct, you
don't want to compute the complicated expressions that
you don't need.  It'd be odd to have

  I(br) <+ (some complicated expression);
  if (off)
    I(br) <+ 0; //does not set branch current to zero!

If it's off (the idea is that the user wanted to turn
the current off), it seems that the user would have
wanted to bypass the complicated expression:
  if (off)
    I(br) <+ 0;
  else
    I(br) <+ (some complicated expression);


The curious nature of the contrib is mentioned explicitly
in my tutorials for writing Verilog-A compact models ...

-Geoffrey



Marq Kole wrote:
> 
> All,
> 
> I would even say that most users starting to write models for Verilog-AMS are quite unaware of this. They write their models as though it were a simple assignment - only in rare cases or when they start to work on more complicated models will they start looking at the actual LRM text and discover the contribution behavior. The same goes for the implicit equations for that matter...
> 
> Just my $0.02.
>

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