News

N-body screensaver available for testing
I wrote a screensaver for the nbody application. You can manually install it and try it from here: http://milkyway.cs.rpi.edu/milkyway/download/nbody_0.92/ (available for Linux, Windows and OS X 64 bit. OS X requires 10.7 Lion). It requires OpenGL 3.2 so it needs a DirectX 10 class GPU (Something newer than Radeon HD 2xxx or GeForce 8000 series)

The screensaver has various mouse and keyboard controls for viewing the simulations. A list of all controls can be accessed by pressing the h or ? keys. You can manipulate the camera by dragging with the mouse and zooming with the scroll wheel.

There are a couple of known problems which you may run into:

- For workunits with larger timesteps, it seems very jumpy. There's an option to update at some interval instead of at every opportunity. There is another option to stop the simulation to wait for the graphics, so that every timestep is drawn as a frame and the animation is smooth.
- The orbit trace view will not do what you expect except when using the option to stop the simulation for the graphics
- The optional axes are ugly
- The preference descriptions aren't very good

I added a bunch of preferences to the web project preferences, but they're not quite finished yet (e.g. the default values don't show up in the boxes when you don't have them set).

I made a small demo video a while ago demonstrating it: http://milkyway.cs.rpi.edu/milkyway/download/random_stuff/nbody_graphics_sample.mp4

Try it out, and see if you like it! If you run into any problems or have any recommendations for future versions, please leave a comment below. 12 May 2012 | 1:48:47 UTC · Comment

New Separation Runs
I started 2 new separation runs today:

ps_separation_09_2s_sample_1
ps_separation_10_2s_sample_1

Post here or in the Number Crunching Message Board if you notice anything strange about them!

-Matthew N 1 May 2012 | 22:47:09 UTC · Comment

UPDATE: Work Stoppage Remedied
It looks as though certain processes got stuck, so I manually killed them then restarted all of the BOINC systems. Things look like they are running smoothly now.

Let me know if you have any more problems.

-Matthew

25 Apr 2012 | 22:39:09 UTC · Comment

Work Stoppage
We are currently experiencing no work going out. This has been escalated to the team and we hope to have it resolved shortly. We are sorry for the delay in the repair.

Blurf 25 Apr 2012 | 17:54:12 UTC · Comment

New Nbody Run
A new NBody run has been posted. We are trying to determine the initial dark matter distribution of some test data. There have been some improvements to our model which should hopefully result in faster convergence times. The run is titled nbody_100K_Plum_EMD. All previous Nbody runs have been taken down. 11 Apr 2012 | 17:46:25 UTC · Comment

New Separation Runs
I've just started up some new runs, with names like "ps_separation_14_2s_..." and "ps_separation_15_2s_...". These runs are designed to study some of the Computer Science that drives Milkyway@home.

As always, let me know if you have any trouble with these work units.

-Matthew N 1 Mar 2012 | 21:21:05 UTC · Comment

Make Up Double Credits Has Now Ended
The 12 hours of double credits, meant to make up for credits lost due to a database error last year, have finished. We are now back to normal credits.

Happy Crunching! 15 Feb 2012 | 3:39:30 UTC · Comment

Makeup Double Credits Now Running
The 12 remaining hours of make-up double-credit is running until 10pm Eastern Time today.

For more info, please see this thread:
http://milkyway.cs.rpi.edu/milkyway/forum_thread.php?id=2761#52813

Happy Valentine's Day! 14 Feb 2012 | 15:24:05 UTC · Comment

Separation updated to 1.00
I've updated all of the separation applications to 1.00. For changes people might care about,

- The old CAL version is gone; it's replaced with the OpenCL application. On AMD/ATI GPUs (older than 79xx) it is using some hackery to use the same IL kernel as before so it should be as fast. However this also means the Radeon 38xx cards aren't supported with new stuff.

- Radeon 79xx stuff should work

- The occasional validate errors from empty / truncated stderr should stop

- AVX will be used if available on Linux and Windows (64 bit only for Windows)

- I've increased the default GPU target frequency so GPU stuff should make things less laggy on average. You can now also configure this with the web preferences now so you don't need to use app_info stuff if you want to play with that.

- Partial workaround with high CPU usage with recent Nvidia drivers.*

As usual post problems you run into here.



* It should cut down on the CPU usage a bit while not sacrificing too much. I would recommend not using it unless you are very unhappy with the CPU usage on Nvidia. There are options to change the polling mode if you want to lower the CPU usage further while not slowing it down. (--gpu-wait-factor (default = 0.75) and --gpu-polling-mode (default = - 2) work similarly to how they did with the old CAL one, but slightly different). With the default of -2 it will use mode -1 unless it is an Nvidia driver newer than the one that introduced the high CPU issue, where it will use mode 0. Mode -1 uses the correct waiting method, mode 0 use the correct waiting method with an initial sleep based on time estimates, and modes > 0 are a polling period in milliseconds. The wait factor is a sort of correction of the time estimate used for the initial wait. The default is 0.75, to wait for 75% of the estimated time before trying to poll. 8 Feb 2012 | 17:36:48 UTC · Comment

Remainder of the Double Credits: A Valentine's Day Present
A few weeks ago, we ran double credits in order to make up for a database error that occurred earlier in 2011. Unfortunately, the server crashed with just 12 hours left until the make-up credits were finished.

Now that the new server is up and running (and stable! very stable!), and everyone here is back from travels and winter break, we are ready to finish running those last 12 hours of double make-up credits.

If there are no significant objections, we'll run the double credits on St. Valentine's Day (February 14), from 10:00 am until 10:00 pm, US Eastern time (EST). This corresponds to 3pm (Feb14)-3am (Feb15) UTC.

Happy crunching! 5 Feb 2012 | 3:25:39 UTC · Comment

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