A user level multi-threaded Particle simulator

1. A user level multi-threaded Particle simulator Supervisor: Joe Cordina Observer: Kurt Debattista

2. APT • Advanced practical task serve the purpose of allowing students to design, implement and document a medium to large project • Student initiative • Understand task + design • Research into possible solutions • Work alone under supervisor’s guidance User LevelMulti-threaded Particle simulator

3. Overview • Designing and implementing a user-level multi-threaded particle-in-a-box simulator. User LevelMulti-threaded Particle simulator

4. Literature • Operating Systems II and Concurrent and Distributed Systems Slides • Any basic mathematics textbook • Any basic physics textbook User LevelMulti-threaded Particle simulator

5. Assessment • 50% Design/Implementation • 30% Documentation/Inception Report • 20% Presentation/Interview User LevelMulti-threaded Particle simulator

6. Main issues of APT • Implementation • Learn how to use Mesh • Provide a multi-threaded particle simulator • 2D view of particles • Provide example scenarios • Calculate basic physics constants • Benchmark your algorithms User LevelMulti-threaded Particle simulator

7. Mesh • Mesh is an advanced very fast user-level multi-threaded library written in C for CERN (Linux). • It is user-level and thus we will try not to make use of system calls as much as possible. • Memory requirements concerns will be of major focus. User LevelMulti-threaded Particle simulator

8. Mesh (cont.) • Your main header files are Mesh.h and Scheduler.h • Main function provided by void Main(Thread* p, int argc, char** argv); void Exit(int code); • A large selection of function calls are available to allow thread manipulation • Note that threads can also have a priority User LevelMulti-threaded Particle simulator

9. Mesh (cont.) • #define Thread_Constructor(F,X...)Scheduler_ThreadConstructor((ThreadMain)(F),X) • void Thread_Destructor(Thread*); • void Thread_Stop(void); • void Thread_Exit(void); • void Thread_NewPriority(int priority); • void Thread_SetPriority(Thread* p,int priority); • int Thread_GetPriority(void); • void Thread_Yield(void); • void Thread_Preempt(void); • void Thread_Join(Thread* process,...); • void Thread_Spawn(Thread*,int priority); • void Thread_Run(Thread*); • void Thread_Runs(Thread* process,...); • void Thread_Par(Thread* process,...); • void Thread_PriPar(Thread* process,int priority,...); • void Thread_SleepUntil(RealTime t); • void Thread_Sleep(RealTime t); • Thread* Scheduler_ThreadConstructor(ThreadMain main,int stack_size,int narguments,...); User LevelMulti-threaded Particle simulator

10. Particle Simulator • Using the threads package you will simulate the behavior of physical particles in a box. • Threads are ideal where each thread performs small amounts of calculation • Thus define box dimensions and let the particles loose in it starting from a random position. User LevelMulti-threaded Particle simulator

11. Particle Simulator (cont.) • Particles in physics have a well defined behavior • Assume that all particles are point particles • When they collide with a wall their angle of reflection equals angle of incidence. • Each particle has a mass and a velocity (speed with direction) User LevelMulti-threaded Particle simulator

12. Particle Simulator (cont.) • Motion is governed by sx = x + v * t * cos a sy = y + v * t * sin a where sx is distance in x direction sy is distance in y direction v is velocity t is time a is the direction angle User LevelMulti-threaded Particle simulator

13. Particle Simulator (cont.) • Particles can also collide with each other • Yet particles have also momentum and physics say that initial momentum should equal final momentum in a collision. • Equations given with handouts • Be careful when calculating theta to get final angle • One of the main task is an efficient collision detection between the particles User LevelMulti-threaded Particle simulator

14. 2D view of particles • You will be using the svgalib man svgalib will tell you all • Compile using gcc –lvga vga_init(); vga_setmode(G640x480x256); • Then you can use • int vga_drawpixel(int x, int y); User LevelMulti-threaded Particle simulator

15. 2D view of particles • The display should be synchronized to 60 frames a second (Bonus). • Make your program decrease the frames per second depending on the load in the computer. • For timing you can use the RealTime Library. User LevelMulti-threaded Particle simulator

16. Basic Physics constants • You can calculate the average speed of the particles, the speed distribution and the velocity distribution. • You can calculate the temperature visible produced by your particles in real-time and you can compare it to the ideal one. • The mean Kinetic Energy has to remain constant in a closed box • When numbers are very large <K> =(mvx2) / N User LevelMulti-threaded Particle simulator

17. Bonus Material • Construct multiple scenarios • Multiple boxes next to each other where each border can store part of the energy of one collision and then pass it on to the next particle that hits it • A leaky box, where if a particle has energy above a certain value, it will escape away • 3D equations and visualization of the system • Hot walls which transfer constant energy to the particles but particles which have larger energy will still escape • Dampening effect in the box • Others you might think of or discussed with me • Optimisation techniques on the algorithms • Producing graphs of physics constants with time User LevelMulti-threaded Particle simulator

18. Benchmarking • Use the RealTime library to be able to benchmark the efficiency of your algorithms. • This will give you time delays in the order of s. User LevelMulti-threaded Particle simulator

19. Documentation • Inception report (Friday 1st March) • Analysis/Design • Work plan • Report • Detailed analysis of problem • Discussion of solution (+ others considered) • Detailed description of data structures and algorithms used User LevelMulti-threaded Particle simulator

20. Presentation • 15 minute presentation • Material Content • Knowledge of subject • Clarity • Interview • Answer questions related to APT User LevelMulti-threaded Particle simulator

21. Interaction • Expect to report to supervisor every other week:Friday • Who cannot attend must mail in progress report + work in progress demo • First meeting Friday 1st March User LevelMulti-threaded Particle simulator

22. The end • All the best! • Good luck! • Work hard! User LevelMulti-threaded Particle simulator