Showing papers on "Gadget published in 2001"

GADGET: a code for collisionless and gasdynamical cosmological

Abstract: We describe the newly written code GADGET which is suitable both for cosmological simulations of structure formation and for the simulation of interacting galaxies. GADGET evolves self-gravitating collisionless fluids with the traditional N-body approach, and a collisional gas by smoothed particle hydrodynamics. Along with the serial version of the code, we discuss a parallel version that has been designed to run on massively parallel supercomputers with distributed memory. While both versions use a tree algorithm to compute gravitational forces, the serial version of GADGET can optionally employ the special-purpose hardware GRAPE instead of the tree. Periodic boundary conditions are supported by means of an Ewald summation technique. The code uses individual and adaptive timesteps for all particles, and it combines this with a scheme for dynamic tree updates. Due to its Lagrangian nature, GADGET thus allows a very large dynamic range to be bridged, 7 both in space and time. So far, GADGET has been successfully used to run simulations with up to 7.5 3 10 particles, including cosmological studies of large-scale structure formation, high-resolution simulations of the formation of clusters of galaxies, as well as workstation-sized problems of interacting galaxies. In this study, we detail the numerical algorithms employed, and show various tests of the code. We publicly release both the serial and the massively parallel version of the code. © 2001 Elsevier Science B.V. All rights reserved.

Gadget: A Tool for Extracting the Dynamic Structure of Java Programs.

Abstract: Source code analysis and inspection does not provide enough information to describe the structure of an objectoriented program completely because there are components and relations that only exist during its runtime. This paper presents a tool, called Gadget, that helps software engineers extract the dynamic structure of objectoriented programs written in the Java programming language. The tool uses program profiling, filtering, and graph clustering techniques. In this work we show how Gadget is used to analyze a standard graphical user interface library for Java, called Swing. This library has a complex structure, part of which we expose using data gathered by Gadget during the execution of a simple Java program that uses Swing.

Computer system for assisting the collection of gadgets and method for assisting the collection of gadgets using a computer system

Abstract: A computer system for assisting collection of a gadget, the computer system including: an acquisition section for acquiring usage information representing how the gadget has been used; a calculation section for calculating, based on the usage information, an estimate of a sum of money to be paid to a client in exchange for the gadget to be collected or a sum of money to be paid by the client as a usage fee for the gadget; and a transmission section for transmitting the calculated estimate to the client.