Re: [SOSlib-discuss] copyVariableState() and setVariableValue() issues[Scanned]

[Eric F. <efe...@ph...>]

Hi Rainer,

A stricter (lower) error tolerance has helped a lot, convergence issues
disappear for the subsequent steps when using the non Jacobian solver.
However, I cannot use Jacobian at all for the first step, it never
converges succesfully. You must be right regarding the particular state
of the initial conditions.

Regards,
Eric

> -----Original Message-----
> From: Rainer Machne [mailto:ra...@tb...] 
> Sent: 17 November 2008 01:45
> To: Eric Fernandez
> Cc: sbm...@li...
> Subject: Re: [SOSlib-discuss] copyVariableState() and 
> setVariableValue() issues[Scanned]
> 
> Hi Eric,
> 
> sorry for the late reply, I have just moved to Japan for a year.
> 
> On Sat, 8 Nov 2008, Eric Fernandez wrote:
> 
> >
> > Hi,
> >
> > I reply to myself regarding the usage of setVariableValue() 
> : indeed 
> >it works as intended. However, I get the same problems than with
> >copyVariableState(): when the integration is solved with a Jacobian 
> >matrix, I get a convergence test error as soon as I do the first 
> >integration step. I wonder why there is a problem, shouldn't an 
> >integrator instance behave normally if the initial conditions are 
> >changed?
> 
> I guess, I should have a look at copyVariableState, if it 
> still works as intended after all the changes made.
> 
> However, I think the situation you described can happen. The 
> new initial conditions might put the system close to some 
> hard-to-solve stiff state, and a running solver might have 
> it's internal time steps etc. already set-up for this 
> situation, while a newly starting solver has problems with 
> the same conditions. Maybe you could try to play with the 
> error tolerances and printstep size?
> 
> But you are right, the CVodeReInit caused by events should 
> have the same or similar effects on an already running itnegrator.
> 
> Are there any news regarding this problem?
> 
> Rainer