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Date: Mon, 25 Mar 2019 17:06:41 +0100
From: mhx AT iae DOT nl
To: geda-user AT delorie DOT com
Subject: Re: [geda-user] Netlist --> Linear state space model
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On 2019-03-25 15:44, Nicklas Karlsson (nicklas DOT karlsson17 AT gmail DOT com)
[via geda-user AT delorie DOT com] wrote:
> I think this is the most appropriate forum to ask. Do anybody know
> about a tool to Convert a netlist to a linear state space model?
> 
> This form is commonly used in control theory. It may be of great use
> both for simulation and calculation of control parameters.
> 
> In the thesis "Automatic generation of optimal concurrent error
> detection circuits for linear timeinvariant analog electronic systems"
> marked Eindhoven University Of Technology author Peters, A.W. mention
> he wrote some software in Octave for this purpose.

As a net-list is a lossless representation of a circuit diagram, this
question is equivalent to: "Does software exist to convert a circuit
diagram to a linear state space model?" The answer is yes. One should
first linearize the circuit (not trivial e.g. for power electronics or
switched capacitor circuitry), then use the algorithm in Chua and Lin's
classic book "Computer-Aided Analysis of Electronic Circuits: Algorithms
and Computational Techniques". The algorithm is in matrix form and
ready to type in MATLAB (and therefore Octave).

The other route is to go from a net-list to MNA form (Ruehli and all), 
and
then use the technique in (can't find the paper now, send me an e-mail) 
to
go from MNA to A,B,C,D / state-space form. The paper cuts some corners
when the sources are higher-order non-differentiable, but that isn't
very common in practice (I don't believe yet the paper is correct, but
they got it published :-)

BTW it is very easy to convert a circuit diagram to SS form by hand,
much easier than to even begin to write a program to do it 
automatically.
The really tricky step is to do a correct linearization.

-marcel