so to answer your questions:
1). Just observe the simulation with a very small frame rate. You can
also observe "one particle in gravity" with the "Semi implicit Euler"
algorithm and you will see that the particle goes down under, i.e. it
decreases its velocity and vanishes. For the normal simulation the
particles come back, but they go to much "into the wall". To make
things clearer, I am attaching another picture from the simulation.
Observe the particle in the bottom right corner;
2). I have just test under the hardwall boundary conditions, for the
periodic conditions does not exists this kind of problem;
3). The graph named 01.05 it is from yesterday, sorry, my mistake, it
should be named 11.07, and the graph named 26.04 was from before, i.e.
in the period between 26.04 and 01.05 (I wanted to name them after the
4). On the plot you can see that particles are going under the
horizontal line named "x/[px]" in the plot. This line represent all
the points on the graph with zero y - coordinate (y = 0). All the
points above that line have a positive y - coordinate and all the
points under have a negative y - coordinate. A particle muss not have
a negative y - coordinate, i.e. that means that a particle goes out of
the simulation area.
The other bugs that I have fixed are just a minor thing for the
writing function, so it does not affect the simulation at all and I
will make a pull request for it, but I was kind of busy trying to find
the problem with the boundaries. :-)
2012/7/12 Jan Kis <jano...@gmail.com