[FLASH-USERS] Orbit problem

[clementel at strw.leidenuniv.nl]

Dear Flash users,

I'm trying to write a code to describe the elliptical orbit of a binary
system, with particles of different mass.
I want the stars as active particles because I also need to compute the
gravitational acceleration field due to the stars, but since with the self
gravitating stars orbit I didn't obtain close orbit I want to move the
stars computing the positions by solving Kepler's Equation.
The problem is that if I set use particles = to true the code want to move
the particles and so I replace  the standard pt_advanceActive with my
subroutine call.

Everything seem to work except the fact that sometimes the two particles
exchange (i.e. particles 1 believes to be particles 2) and so I have this
particles bouncing between the two possible elliptical orbit.

Is it possible do what I'm trying to do?
What I could did wrong to obtain this behavior?

Thanks,

Nicola Clementel