Here is an overview of Particula Numerica 3.0.
Particula is a physical simulator to simulate a system of many point masses using the equation of motion. Particula shows the dynamics of the masses beginning from a certain initial condition. In the field of astrophysics, this kind of simulator is called N-Body simulator.
N-Body simulators calculate the all forces between the every two of them and accumulate the total forces for each body. Then using the evaluated forces, the simulators solve the equation of motion of each body.
The basic algorithm are quite simple, but in the case of large N, there is a serious problem.
The total amount of computation become quite large in the order of square of N calculation for gravity forces. This is very serious problem with large N. As for molecular dynamics or plasma simulator could be neglect the force from the bodies in a far area. This is because the electromagnetic force are composed of positive and negative forces, often there are canceled each other. But the force of gravity only has an attractive force so the effect of force cannot be eliminated.
So an algorithm to reduce the computaion by merging masses into single mass point in a distant area using octet-tree area division. Particula has the algorithm and moreover an original method is implemented using Alternate digital tree algorithm.
Particula Numerica shows the result in real time as an animation, which is a common character of Three Wells' Physica Numerica series softwares. You can save snapshot image of the 3D view in PNG format in a certain time interval. This gives you a lot of information in spite of your absence in front of the computer monitour.
NEMO format, a famous format in numerical astrophysics field, is supported for I/O. Why don't you try Particula Numerica, it's FREE! Please find your own Galaxy in your monitour. Please download the software and try it!.
As a new topic, the source code of the software is opened at GitHub. Please enjoy it. Astrophysicists studied with the code adding non-Newtonian force and dark matter effects actually.
Please take a look a sample movie for galaxies collide simulation in the bottom of this article and the other samples.