gadget computes gravitational forces with a hierarchical tree algorithm (optionally in combination with a particle-mesh scheme for long-range gravitational forces) and represents fluids by means of smoothed particle hydrodynamics (SPH). The code can be used for studies of isolated systems, or for simulations that include the cosmological expansion of space, both with or without periodic boundary conditions. In all these types of simulations, GADGET follows the evolution of a self-gravitating collisionless N-body system, and allows gas dynamics to be optionally included. Both the force computation and the time stepping of GADGET are fully adaptive, with a dynamic range which is, in principle, unlimited.
gadget can therefore be used to address a wide array of astrophysically interesting problems, ranging from colliding and merging galaxies, to the formation of large-scale structure in the Universe. With the inclusion of additional physical processes such as radiative cooling and heating, GADGET can also be used to study the dynamics of the gaseous intergalactic medium, or to address star formation and its regulation by feedback processes.
An updated (2020) version uses the mknemo(1NEMO) command
Note that for each style of gadget a special Makefile is used to compile this executable. Examples can be found in Gadget-2.0/Gadget2/parameterfiles/
There is no rungadget NEMO front-end for this complex program (yet). It is left as an excersize for the writer.
% time mpirun -np 1 Gadget2/Gadget2 Gadget2/parameterfiles/galaxy.param > galaxy.log AMD64/3200: 2126.093u 2.983s 35:29.48 99.9% 3294.859u 7.763s 55:10.38 99.7% ??? np=1 0.000u 0.000s 55:04.35 0.0% 0+0k 0+0io 0pf+0w np=2 0.000u 0.002s 36:44.69 0.0% 0+0k 0+0io 0pf+0w np=4 0.000u 0.002s 39:18.13 0.0% 0+0k 0+0io 0pf+0w AMD Opteron 246/2000 2160.138u 2.687s 36:02.81 100.0% P4/3300 desktop: about 1h18m/2 = 78/2 = 2340" ? P4/1600 laptop: about 4h35m 16508" P4/64/3000 3292.062u 7.109s 55:05.93 99.7% G5/1600 4263.6u 51.5s 1:19:07.64 90.8%
http://www.mpa-garching.mpg.de/gadget/ Springel V. (2005MNRAS.364.1105S) - The cosmological simulation code GADGET-2 (gadget2-paper.pdf) Springel V. May 1, 2005 - User Guide for GADGET-2 (users-guide.pdf). Springel V., Yoshida N., White S. D. M., 2001, New Astronomy, 6, 51
15-mar-2000 V1.0 original fortran version released (Y2K compliant!) 1-may-2005 V2.0 rewritten in C++ 17-mar-2006 a first document in NEMO 14-feb-2020 some notes after mknemo install option
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