[ODE] ODE Message 3: LCP internal error, s <= 0 (s=0.0000e+00)

[Adam D. Moss]

Olivier Michel wrote:
> Hi,
> 
> I often get the following ODE message after my simulation has run for a 
> while:
> 
> ODE Message 3: LCP internal error, s <= 0 (s=0.0000e+00)
> ODE Message 3: LCP internal error, s <= 0 (s=-0.0000e+00)
> ODE Message 3: LCP internal error, s <= 0 (s=nan)
> ODE Message 3: LCP internal error, s <= 0 (s=0.0000e+00)
> 
> which blows out my model...
> 
> I could I avoid this ? Use double precision instead of single precision 
> floating point numbers in ODE ?
> Reset somehow my simulation after a given amount of time ?
> 
> Any hint would be highly appreciated.

Double precision would probably help a bit, but numerical stability
is a general plague in simulation.  See sections 12.12 and 11.4 in
the ODE manual for stability hints -- the unhappy answer is that
getting (almost!) rid of these situations basically often
comes down to lots of hand-tuning of constants and parameters.

Regards,
--Adam
-- 
Adam D. Moss   . ,,^^   adam at gimp.org   http://www.foxbox.org/   co:3
"At this point the rocket becomes engorged with astronauts."