getDP question

[Uwe Pahner]

Thanks for the quick answer. I will try it out next Monday, as I am on
holiday tomorrow.

Have a nice weekend.

Uwe
At 04:43 PM 8/24/00 +0200, you wrote:
>Uwe Pahner wrote:
>> 
>> Dear Christophe,
>> 
>> I am using getDP to solve a transient, coupled magneto-thermal problem.
>> Maybe Francois Henrotte contacted you about this. Anyhow, he is on
>> holidays, so I cannot ask him a question on getDP (on which I don't find an
>> answer on the getDP homepage).
>> 
>> Attached you find the .pro files related to this model. I am running a
>> transient analysis, where in each time step a coupled problem is solved
>> (resolution 'TRA' in 1cond.pro). The model is a wire that is heated up
>> using three consecutive induction heating devices. The numerical problem I
>> am having is that using different time-schemes (Theta = 0.75 ... 1.0) and
>> time-steps (DTime = 0.025 .. 0.1 s) results in very different solutions.
>> The strange thing is that the divergence of the different solutions starts
>> after the wire has passed the first oven. In other words, after a fixed
>> time. I want to investigate the problem further, changing some of the
>> parameters. But this would always require very long analysis runs, as I
>> always need to compute the first oven again. I just want to solve once
>> until time T1, and then restart with different TimeLoop settings from there
>> onwards.
>> 
>> My question:
>> 
>> Is there a possibility to restart the transient loop from an already
>> existing solution even when changing some of the TimeLoop settings? There
>> is the "-restart" option when starting up getDP. But I was assuming that
>> this only works if I don't change the TimeLoop settings. Do you have any
>> suggestion?
>
>Hello Uwe,
>
>No, you should be able to use the '-restart' flag, even if the
>parameters of the time scheme are changed. With '-restart', GetDP just
>reads the last solution (for first order time schemes) and uses it as a
>starting point for the upcoming computation. In other words, the
>parameters used in the time stepping algorithm are those which are read
>in the '.pro' file when the '-restart' is performed.
>
>If it does not work, tell me on which platform you are working. I'll
>send you a new version of the code so that we will be able to track down
>the problem on a recent version (the handling of time has changed quite
>a lot in the code since the last few months).
>
>My best,
>
>-- 
>Christophe Geuzaine
>
>Tel: +32-(0)4-366.37.10    mailto:Christophe.Geuzaine at ulg.ac.be
>Fax: +32-(0)4-366.29.10    http://www.geuz.org
>