[SI-LIST] Re: New numerical method for EM problems.
- From: "Lars Juul" <write2larsj@xxxxxxxxx>
- To: si-list@xxxxxxxxxxxxx
- Date: Mon, 13 Oct 2008 09:26:00 +0200
TLM is what came to mind, here as well. There is an existing TLM tool called
Microstripes, I took it for a spin and was impressed, compared to my HFSS
experience.
Anyway, Walter, could you post some links for us to see your material? You
can't attach stuff to freelists.
Lars
2008/10/12 walter steffe <steffe@xxxxxxxxxx>
> Hi Steve,
> you have rised a lot of important questions. Now I will try to answer to a
> few of them. I will come back next to give a better picture.
>
> Up to now my method has been tested only on a few test cases but in
> priciple
> it should work on any closed problem (for the moment I do not intend to
> address
> antennas problems).
> The most complex test I have done is an interdigital filter. This exercise
> is
> described in the two attached pages which are extracted from my Informl
> Business
> Plan. There you can see the domain decomposition and the kind of mesh I am
> using
> (each subdomain is described by a its meshed boundary).
>
> On a single processor the computational time required to solve this test
> case with
> my method is not much different that time used by the other commercial
> simulator.
> My method is anyway much more well suited for the parallelization because
> the computations
> of the different subcircuits are independent tasks. Other methods are much
> more difficult
> to parallelize in an efficient way due to the large amount of data exchange
> among the
> different parts of the computational domain.
> So I am thinking to deploy my software on a large grid (as the Sun Grid)
> and sell
> it as a service. In this way the customer will be able to get a quick
> result and,
> at the end, he will have to pay only for the actual work (measured as total
> CPU time)
> and not for the number of used processors (as it happens with the more
> traditional
> licence scheme).
>
> An other important difference is in the kind of result that is provided.
> In my view a spice circuit is much more valuable than a set of curves.
> It is true that there exist some techniques which allow to extract an
> equivalent circuit from a set of simulated (or even measured) data.
> I do not think anyway that these methods can work very well with large
> circuits and expecially with a large number of ports (let say 1000 ports).
> With my method every big problem can be split in a large number of small
> subproblems that are solved in parallel. Today the processors are quite
> cheep
> but you have to be able to parallelize your computation in an efficient
> way.
>
> A third important advantage, which is also related to the domain
> decomposition
> strategy, comes into pay when there is the need to perform an optimization.
> Here my method can achieve a dramatic imrovement in the computational
> efficiency
> because a local change in the geometrical or physical parameters of a given
> subdomain affects only the related subcircuit and there is no need to
> recompute
> the subcircuits associated with the other (unchanged) parts.
> All other traditional full-wave simulators treat the electromagnetic device
> as
> an unstructured black box and need a complete rexecution after any small
> change
> of the structure.
>
> The previus comments are a (partial) responce to your points 1 and 3.
> For what concerns point 2 it is too early to say that my method can not
> break down where others do well. The actual behaviuor of my method will
> also depend on the quality of the domain decomposition and of the mesh.
> The development of a software tool which is able to perform an automatic
> domain decomposition with a good quality is my next high priority.
> Up to now the test cases have been generated with an academec and very
> rudimentary software tool. This is the main reason of my difficulties in
> the preparation of an exhaustive set of benchmarks.
> On the other side I can say that, for sure, there is a case where all other
> full-wave methods fail and my method performs very well.
> This case is the accurate characterization of the electrical response near
> the zero frequency. Other methods became very ill conditioned (FEM and MoM)
> or very inefficient (FDTD) when the frequency approaches zero.
> Of cource you can use a quasistatic method which give an accurate result
> near
> the zero frequency but in this case you will have bad results at the higher
> frequencies. If you want an equivalent circuit that is accurate over the
> full
> band (from zero to the highest freq) my method is the only choice.
>
> To summaryze my view of case I would say that:
>
> 1) My method exibit clear advantages in a few important areas and this
> gap can not easely be filled by other methods.
> 2) The market value of these advantages is not totally claer to
> me because I am not an expert of SI (which I thing is the most
> interesting market of my software). I hope that this forum will
> help me to gain a better insight on this subject.
> 3) I would prefer to avoid involving an univerity because I would
> have to publish too many details which would decrease the value
> of my invention.
> 4) There is still work to be done in order to reach the point where
> my software is at least minimally commercially viable.
> The highest priority is the development of a good
> CAD/mesh interface.
>
>
>
> Walter
>
>
>
>
> On Sun, 2008-10-12 at 02:57 -0700, steve weir wrote:
> > Walter, I see a couple of challenges:
> >
> > 1. Proof that the method works as intended over a useful range of
> problems.
> > Do those problems cover all the types of problems that existing tool /
> > tools handle?
> > What problems can it handle that existing tools can't or can't handle
> > well. Why? Other than adopting your method, what might an existing
> > vendor do to cover the gap?
> >
> > 2. Determination if and where the method has exceptional cases.
> > Are there situations where the method breaks down or generates results
> > that are less accurate than existing products?
> >
> > 3. Ultimate computational efficiency of the method for common problems.
> > Can the method solve problems handled by existing tools on similar
> > computer platforms and in similar or better run times?
> >
> > 4. Ultimate accuracy of the method for common problems.
> > Are the results similar, better, or worse than those generated by
> > existing tools.
> >
> > 5. A business plan that shows that if the method does everything that
> > you believe it does that investors would see a profit from it.
> > Better mousetraps can be a hard sell. Is there an application area
> > where the method is or will in the near future become a "must have"?
> >
> > It can take years to get through the first four steps, and then many man
> > hours to code the results into a tool and test it rigorously. It can be
> > very difficult to convince an established player that the risk and
> > investment is worthwhile. In order to do that, you will need to be able
> > to show that your method has commercial value either by: providing
> > greater accuracy, faster results, supporting problems they cannot, or
> > some combination of all three that provide compelling value versus the
> > costs required to develop and deploy it.
> >
> > There are several ways that you might start:
> >
> > 1. Write one or more academic papers that compare the method to others
> > and show what it can do / can do better than other methods.
> > 2. Get support from a university as a cosponsor to the property to
> > develop it to the point that it is at least minimally commercially
> > viable. Universities are cheap sources of labor and many also have good
> > relationships with industry.
> > 3. If you can show that the method addresses a critical high dollar
> > problem today, or one that will become apparent within a short time
> > frame, you may be able to attract investment capital.
> >
> > Off hand I think that the commercial targets for you would be 2.5D
> players.
> >
> > Steve.
>
>
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>
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