Message boards :
MilkyWay@home Science :
N-Body Plots
Message board moderation
Author | Message |
---|---|
Send message Joined: 6 May 09 Posts: 217 Credit: 6,856,375 RAC: 0 ![]() ![]() |
We have some new images from Ben Willet's work on the N-Body project. What follows is a technical description; another, less technical explanation will follow later. ![]() Shown in purple is an N-body simulation of the Orphan Stream using the latest orbit. The Milky Way is shown edge-on, with the disk represented by a line, the Galactic bulge in the center, and the Sun's position indicated by the yellow dot.The observed stars in the Orphan Stream were ripped from a dwarf galaxy by the gravity of the Milky Way galaxy. The star stream has been labeled "Orphan" because no one has yet yet positively identified the parent dwarf galaxy from which these stars were ripped. Image Credit: Benjamin A. Willett ![]() This animation shows N-body simulations of tidally stripped mass forming the Sagittarius (large), Orphan (medium) and GD-1 (small) stellar streams. The Sagittarius and Orphan streams are formed by tidal stripping from small dwarf galaxies that have passed too close to the center of the Milky Way, while the GD-1 stream is formed by tidal stripping of a globular cluster. The Milky Way Galaxy is shown edge-on, with the Sun located on the left side of the disk. The line on the top right shows the +Z direction, out of the Galactic disk. The entire animated sequence represents four billion years of elapsed time in the Milky Way, ending at the present day. Image Credit: Benjamin A. Willett |
![]() Send message Joined: 11 Jun 10 Posts: 329 Credit: 1,166,222,661 RAC: 0 ![]() ![]() |
OMG it's a closed timelike curve, lol! Way cool and good to be part of this work! |
![]() ![]() Send message Joined: 24 Jan 11 Posts: 712 Credit: 551,845,018 RAC: 44,095 ![]() ![]() ![]() ![]() |
Very impressive simulation and excellent explanation of the galaxy stripping process. Keith ![]() |
![]() Send message Joined: 3 Oct 10 Posts: 42 Credit: 320,242 RAC: 0 ![]() ![]() |
Thats fantastic. And to watch that and to think my PC had some small part in helping figure that out. :) So you are having our CPU's do the N_body work and the GPU's do something else? What is the difference? In retard terms please. :) 32bit Windows XP Home AMD Opteron 180 ASUS A8N-SLI Motherboard Nvidia 450GTS GPU 4GB DDR Memory |
Send message Joined: 1 Dec 12 Posts: 2 Credit: 10,394,617 RAC: 0 ![]() ![]() |
What happened with the animation of this thread? Sunday was working. Today disappeared :''( |
![]() Send message Joined: 18 Jun 13 Posts: 1 Credit: 14,760 RAC: 0 ![]() ![]() |
Hi, I just signed in and earned 5k credits. This program uses N*N interactions or some Barnes-Hutt involved to make it N*log(N)? |
![]() Send message Joined: 23 Sep 12 Posts: 159 Credit: 16,977,106 RAC: 0 ![]() ![]() ![]() |
This uses Barnes Hut for N Log(N) but as the systems are non-linear(chaotic) some parameters will scatter and when a Barnes Hut system is widely scattered it approaches N^2. So Barnes Hut is optimally N Log (N) but in worse case is N^2. The systems we study vary in case part of what we are learning about the systems. Jeff |
![]() Send message Joined: 2 Oct 14 Posts: 43 Credit: 55,027,156 RAC: 861 ![]() ![]() |
The graphics processor unit (GPU) is a specialized processor. It takes an image stream the computer wants to present on the monitor and transforms it into something the monitor can use efficiently. Techies call this "graphic acceleration." It uses its chip real estate to do some (but not all) these things separately because the central processing unit (CPU) has better things to do. The GPU has its own reduced instruction set. With a little help from the CPU, it can do the work of an additional core of the CPU. A mini-program is the "gatekeeper" that uses the CPU to do what the GPU cannot do, and feed it with stuff the GPU can do. The GPU's result is passed back to its feeder. Meanwhile, the CPU is doing something else while the GPU is doing its thing. The GPU is doing something that it was not designed to do. It does not know or care. It just does what the CPU told it to do. Modern CPUs contain more than one processor on a single piece of silicon. Using electronic magic, they share work space. That way, we get to process more than one operation at the same time. The central processor unit is a collection of processors called "cores." MilkyWay@home does not provide the feature that can fool a GPU into doing the work of a processor core. However, MilkyWay@home does have a way to use all of the cores of the CPU for a single task to crunch through a simulation. Other projects offer a GPU feature. SETI@home is an example. My machine has an Intel i7 processor that can do up to 8 things at once (8 cores). One core plays "musical chairs" with a GPU. That is why my machine shows that it is doing 9 things at once. MilkyWay is doing 8 things in one task. SETI is doing one other thing using the GPU. If MilkyWay is not doing a simulation, SETI and MilkyWay are doing 9 things at the same time. |
Send message Joined: 10 Jan 15 Posts: 9 Credit: 44,795,441 RAC: 0 ![]() ![]() |
Ive had to kill three over 4 hours Nbody v1.5 looping. 5 min. task Im aborting after 4+ hours running 8 processers. I7, Win 7 Pro-64 bit, 12 GB Ram, 2 TB HD. Leelan Coin leelan.coin@gmail.com Name ps_nbody_5_12_15_orphan_sim_1_1431361804_27915_0 Workunit 823277835 Created 14 May 2015, 14:43:11 UTC Sent 14 May 2015, 15:23:55 UTC Report deadline 26 May 2015, 15:23:55 UTC Received --- Server state In progress Outcome --- Client state New Exit status 0 (0x0) Computer ID 605363 Run time CPU time Validate state Initial Credit 0.00 Device peak FLOPS 32.39 GFLOPS Application version MilkyWay@Home N-Body Simulation v1.50 (mt) Stderr output |
![]() ![]() Send message Joined: 6 Apr 12 Posts: 42 Credit: 3,215,609 RAC: 0 ![]() ![]() |
I wonder if these stars ever collide with each other :) |
Send message Joined: 26 May 11 Posts: 32 Credit: 43,959,896 RAC: 0 ![]() ![]() |
Please advise how stars with different life spans, size - weights, "burning"... effects the calculations? If the plot below represents 4 billion years, I would think there would be some "changes" do to star life, size, and weight spans. Or in the scheme of things are these factors considered too small - insignificant to consider? |
Send message Joined: 28 Jul 13 Posts: 9 Credit: 3,099,041 RAC: 0 ![]() ![]() |
Can this data be used to update the overview page written in 2013? It would be good to get an idea of overall progress and future directions |
Send message Joined: 25 Feb 13 Posts: 580 Credit: 94,200,158 RAC: 0 ![]() ![]() ![]() |
Hey iancantwell, We will be updating the science page eventually. It is on my list of things to do this summer, but that this is quite long at the moment. Jake |
©2024 Astroinformatics Group