Package edu.rit.clu.antimatter

Package edu.rit.clu.antimatter provides the Antimatter Simulation, an example of an N-body problem.

See:
Description

Class Summary

AntiprotonAni	Class AntiprotonAni is a sequential program that calculates the positions of the antiprotons as a function of time and displays an animation on the screen.
AntiprotonClu	Class AntiprotonClu is a cluster parallel program that calculates the positions of the antiprotons as a function of time.
AntiprotonClu2	Class AntiprotonClu2 is a cluster parallel program that calculates the positions of the antiprotons as a function of time.
AntiprotonClu3	Class AntiprotonClu3 is a cluster parallel program that calculates the positions of the antiprotons as a function of time.
AntiprotonFile	Class AntiprotonFile provides an object for reading or writing a series of snapshots of antiproton positions from or to a file.
AntiprotonPlot	Class AntiprotonPlot is a main program that plots antiproton position data.
AntiprotonSeq	Class AntiprotonSeq is a sequential program that calculates the positions of the antiprotons as a function of time.
TrapFrame	Class TrapFrame is a UI window that displays the positions of antiprotons and the total momentum in the Antimatter Simulation.
TrapPanel	Class TrapPanel is a UI that displays the positions of antiprotons in the Antimatter Simulation.

Package edu.rit.clu.antimatter Description

Package edu.rit.clu.antimatter provides the Antimatter Simulation, an example of an N-body problem.

The Antimatter Simulation program calculates the motion of a number of antiprotons moving in a two-dimensional plane. The antiprotons have equal, negative charges. Each antiproton experiences a repulsive force from every other antiproton that is directly proportional to the product of the antiprotons' charges and is inversely proportional to the square of the distance between the antiprotons. A magnetic field is imposed perpendicular to the plane of the antiprotons. As each antiproton moves, the magnetic field exerts a force on the antiproton that bends its path into a circle.

The Antimatter Simulation program maintains each antiproton's position, velocity, and acceleration. The program calculates the positions and velocities as a function of time by doing a series of discrete time steps. At each time step, the program calculates the total acceleration of each antiproton (due to repulsive forces from all other antiprotons plus the magnetic force), updates the velocity based on the acceleration, and updates the position based on the velocity and acceleration:

v' = v + δ a

p' = p + δ v + 1/2 δ² a

where a is the acceleration, v is the velocity before the time step, v' is the velocity after the time step, p is the position before the time step, p' is the position after the time step, and δ is the size of the time step. (These formulas represent the first few terms in the Taylor series expansions for velocity and position as a function of time.)

The cluster parallel programs in this package use Parallel Java (PJ) in package edu.rit.pj.