On Sat, Oct 25, 2008 at 8:24 AM, henrik johansson <[EMAIL PROTECTED]> wrote:
>
> Hi Ondrej and Travis,
>
> I have looked through Travis code and compared it to mine. And there
> are some differences
> in the way the matrices are constructed. And mine is more
> heavyweighted with more dependencies.
>
> Here are some features:
> * numeric and symbolic solutions
> * Pythonic interface for entering circuits that is similar to eispice
> * ac, dc, noise analyses
> * 2-port analysis that calculates 2-port parameters of a circuit
>
> Like Travis I also have problems with large expressions that are slow
> to simplify. There
> is also a need to do approximations. I have been looking into a method called
> Determinant-Decision-Diagrams [0] which is a compact representation of
> determinants where
> approximations can be done before the full result expression is
> developed. Unfortunately
> I didn't come that far.
>
> Anyways, here is an example to whet your appetite :-)
>
> # Construct circuit, in this case a resistive voltage divider
>>>> R1=Symbol('R1', real=True)
>>>> R2=Symbol('R2', real=True)
>
>>>> c = SubCircuit()
>>>> n1,n2 = c.addNodes('net1', 'net2')
>>>> c['vs'] = VS(n1, gnd, v=Symbol('V'))
>>>> c['R1'] = R(n1, n2, r=R1)
>>>> c['R2'] = R(n2, gnd, r=R2)
>
> # Perform a symbolic noise analysis
>>>> res = SymbolicNoise(c, inputsrc=c['vs'], outputnodes=(n2,
>>>> gnd)).run(Symbol('s'), complexfreq=True)
>
> # Print input and output referred voltage noise PSD
>>>> simplify(res['Svnout'])
> 4*R1*R2*kT/(R1 + R2)
>>>> simplify(res['Svninp'])
> 4*R1*kT*(-R1 - R2)**2/(R2*(R1 + R2))
>>>> simplify(res['gain'])
> R2 / (R1 + R2))
Cool, did you make some progress with the release? Looking forward to
look at it. :)
Ondrej
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