GalaxSee

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* Mass of the sun = 1.99 * 10^30 kg
* Mass of the sun = 1.99 * 10^30 kg
* Accelerations are calculated based on the formula found [http://en.wikipedia.org/wiki/N-body_problem here], where gamma in our case is Gnorm = Gconst * mass(sun) / (3 kilo light years / (2 * seconds in 1 million years))
* Accelerations are calculated based on the formula found [http://en.wikipedia.org/wiki/N-body_problem here], where gamma in our case is Gnorm = Gconst * mass(sun) / (3 kilo light years / (2 * seconds in 1 million years))
 +
* There is a Shield Radius, which is the distance between two points under which no gravity takes effect.  This is calculated as 5 * cube_root(Gnorm * mass) * cube_root(time_step^2)

Revision as of 19:54, 30 June 2009

Contents

Problem description

GalaxSee is a simulation of the n-body problem. A galaxy of stars (or point-masses) is generated with random positions and velocities, spun, and updated as the stars exert forces on each other.

Parameters

GalaxSee is run with the following command line: mpirun -np NUMPROCS [-m M] [-t T] [-x] STARS

Classes

Point

A single body. A point has position, velocity, and acceleration, all in <x,y,z> coordinates.

Galaxy

The galaxy initializes the points with random positions and velocities, spins the points around the center, and thereafter makes updates to the points' positions, velocities, and accelerations based on their gravitational interactions with each other.

RunManager

This creates two separate threads. It receives the following commands and executes them accordingly:

World

This is an object-oriented handle to an MPI_Comm. It spawns processes and distributes the work load across them.

Physics Assumptions

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