Re-2: [Getdp] Warning from TransferInitSolution

[m.fenner at gmx.net]

Dear Christophe,

I had some time to visit my wire / TransferSolution problem again. I tried to follow your suggestion using TransferSolution but still got no result. 

What I tried is the following:

I DO NOT solve anything in the dynamical system but just "InitSolution [Tdyn]; SaveSolution [Tdyn] ;" (This starts the pre-resolution "ini" which gives the correct result when run alone.) After that I PostProcess and PostOperate. Then I'd expect to find the solution I got from the pre resolution via TransferSolution. Is that right or have I already messed up the solution by now? Some problem with my syntax e.g.?

I tried this with different Constraints:
a) just setting the Dirichlet constraints (if I understood your suggestion correctly)
b) AssignFromResolution
c) InitFromResolution

but never retrieved my pre-resolution result (see the attached files). But I am still not sure if the pre-resolution actually transfers the data to the system Tdyn - again the question: Where do I loose the information?

When I try to actually solve the dynamical system I get:
a) a rather weird result
b) "Warning   : Generated system is of dimension zero" and T=0 everywhere
c) the same result as a)

There is a work around (for 1-d Systems at least):

Export the data from the pre-resolution, and use the Init Constraint with the linear interpolation of these data. This gives a quite plausible result which actually answers my initial physical question. But a more general solution is desireable, isn't it? Unfortunately I could not get in touch with Ahmed Rassili yet to consult him on his experience.

As far as know there is no working example with TransferSolution in the mailing list archives, too. I shall attach the *.pro, *.geo, and *.dat files I used - just in case you find some time to look at this problem.

Best regards

Matthias

P.S. thanks for the hint concerning the magnetic flux in a sphere. It seems the texbooks on general physics are far too sloppy in their treatment of this stuff. You have to read the specialized literature.

Matthias

                          
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     Matthias A. Fenner

     email: m.fenner at gmx.net                     Hugo-Eckener-Str. 94
     fon: +49 6131 622 10 60                     D-55122 Mainz
                                   
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-------- Original Message --------
Subject: Re: [Getdp] Warning from TransferInitSolution (08-Sep-2004 5:32)
From:    geuzaine at acm.caltech.edu
To:      m.fenner at omicron.de

> m.fenner at gmx.net wrote:
> > Dear Christophe,
> > 
> > I want to solve the nonlinear time-dependent problem of a wire with
> > ends held at different temperatures and an electric current switched
> > on at a certain time. So I solve the 1-d Laplace equation first
> > (resolution ini, system T) and then transfer this solution as an
> > initial condition to the full system (resolution dyn, system Tdyn).
> > ini works allright by itself. But when I try "TransferInitSolution T"
> > I get a "GetDP: Warning: Operation: ???". The dynamical simulation
> > then starts with T~10^-307.
> > 
> > Where do I loose the information of the pre-resolution?
> 
> Hi Matthias - I just checked in the code and we actually never 
> implemented "TransferInitSolution". But I think you should still be able 
> to do what you want by just using "TransferSolution", followed by the 
> regular "InitSolution" on the other system. (At least that's how I 
> remember doing it a loooong time ago.)
> 
> I'm CC'ing Ahmed Rassili on this one: I think he's still using something 
> similar in his simulations.
> 
> Best,
> 
> Christophe
> 
> PS: Thanks for the examples in the Wiki! (I've added a couple of comments.)
> 
> -- 
> Christophe Geuzaine
> Applied and Computational Mathematics, Caltech
> geuzaine at acm.caltech.edu - http://geuz.org
> 

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