Welcome to MilkyWay@home

Nbody Release 1.60


Advanced search

Message boards : News : Nbody Release 1.60
Message board moderation

To post messages, you must log in.

AuthorMessage
Sidd
Project developer
Project tester
Project scientist

Send message
Joined: 19 May 14
Posts: 73
Credit: 356,131
RAC: 0
100 thousand credit badge5 year member badge
Message 64470 - Posted: 14 Apr 2016, 20:39:34 UTC

Hey All,

I just released a new version of Nbody, 1.60. In this version we completely changed the cost function. This is a function that is used in the histogram comparison algorithm. We discovered that the old cost function, which was supposed to allow us to retain the mass data in the normalized histograms, did not account properly for the amount of mass.

This was not a bug, but rather a change in the science behind the algorithm. We would not have rethought the algorithm without the results from MW@H.

As always, if there is any problem, let me know.

Thank you all,
Sidd
ID: 64470 · Rating: 0 · rate: Rate + / Rate - Report as offensive     Reply Quote
KWSN-GMC-Peeper of the Castle Anthrax
Avatar

Send message
Joined: 16 Dec 10
Posts: 21
Credit: 13,709,128
RAC: 0
10 million credit badge8 year member badge
Message 64524 - Posted: 1 May 2016, 22:50:00 UTC
Last modified: 1 May 2016, 22:54:47 UTC

I'm afraid what I'm seeing is 6 hours at a time of multitasking reserving all 4 cores, 8 threads but only using less than 20% of my total CPU.

nope. my mistake. when I exited the BOINC mgr. that process continued...process not completing not the first time i've seen this...

I'm going to have to turn these off till you stop wasting hours of my CPU time.
;
ID: 64524 · Rating: 0 · rate: Rate + / Rate - Report as offensive     Reply Quote
ProfileWisesooth

Send message
Joined: 2 Oct 14
Posts: 39
Credit: 36,263,369
RAC: 27,182
30 million credit badge4 year member badge
Message 64539 - Posted: 7 May 2016, 1:06:44 UTC

Hello Sid,
Reference UID 1028971 Task 1584882935 sent 4 May 20:16:12 UTC
Reported/expired 6 May 4:40:20 UTC on my machine 683929
Task consumed run time 90:487:50 CPU: 337,941.60
This is a 4 month old machine with an Intel i5-6000 3.30 GHz CPU and 8 GB RAM on board.
Hope this helps you. Wisesooth
PS: I did some design work on your GO button. Did Heidi share it with you?
ID: 64539 · Rating: 0 · rate: Rate + / Rate - Report as offensive     Reply Quote
sjmielh

Send message
Joined: 9 Aug 09
Posts: 8
Credit: 3,536,699
RAC: 1,146
3 million credit badge10 year member badgeextraordinary contributions badge
Message 64543 - Posted: 8 May 2016, 10:50:43 UTC - in response to Message 64470.  

Hi,

I get "atos cannot load symbols for the file milkyway_nbody_1.60_x86_64-apple-darwin__mt for architecture x86_64" error on some of the new nbody workunits
http://milkyway.cs.rpi.edu/milkyway/result.php?resultid=1587075175
http://milkyway.cs.rpi.edu/milkyway/result.php?resultid=1586520635

atos seems to be https://developer.apple.com/legacy/library/documentation/Darwin/Reference/ManPages/man1/atos.1.html
ID: 64543 · Rating: 0 · rate: Rate + / Rate - Report as offensive     Reply Quote
Dr Who Fan
Avatar

Send message
Joined: 8 Aug 08
Posts: 21
Credit: 330,385
RAC: 122
100 thousand credit badge10 year member badge
Message 64544 - Posted: 12 May 2016, 3:53:21 UTC
Last modified: 12 May 2016, 3:53:55 UTC

Killing this one off... Only 6.919% done in 21:39:49 CPU HRS
Running WAY TO SLOW

Name ps_nbody_5_3_16_v160_1_inertia_p95_1461261003_1206610_0
Application	MilkyWay@Home N-Body Simulation 1.60 (mt)
Workunit name	ps_nbody_5_3_16_v160_1_inertia_p95_1461261003_1206610
State	Running
Received	11-05-2016 11:35
Report deadline	23-05-2016 11:35
Estimated app speed	2.25 GFLOPs/sec
Estimated task size	3,402 GFLOPs
Resources	4 CPUs
CPU time at last checkpoint	21:39:49
CPU time	21:43:04
Elapsed time	07:25:17
Estimated time remaining	99:50:36
Fraction done	6.919%
Virtual memory size	41.73 MB
Working set size	42.35 MB
Directory	slots/4
Process ID	3348


ID: 64544 · Rating: 0 · rate: Rate + / Rate - Report as offensive     Reply Quote
ProfileThunder
Avatar

Send message
Joined: 9 Jul 08
Posts: 85
Credit: 44,842,651
RAC: 0
30 million credit badge10 year member badge
Message 64547 - Posted: 12 May 2016, 21:02:05 UTC
Last modified: 12 May 2016, 21:09:38 UTC

Task 1591663252 is my current record holder at CPU time 7 days 16 hours 47 min 52 sec

The long run time doesn't bother me in the slightest as long as something useful spit out in the end.

I'm curious as to what these "inertia" units are actually doing though, because their run times vary by huge amounts (some take as little as 30 minutes of CPU time or in this case as long as 7.75 days).

So... what's up with that?

Edit: Actually I found the shortest I've done is 99.21 seconds and the longest is 665,272.70 seconds. :-)
ID: 64547 · Rating: 0 · rate: Rate + / Rate - Report as offensive     Reply Quote
Sidd
Project developer
Project tester
Project scientist

Send message
Joined: 19 May 14
Posts: 73
Credit: 356,131
RAC: 0
100 thousand credit badge5 year member badge
Message 64571 - Posted: 25 May 2016, 17:18:28 UTC - in response to Message 64547.  

Hey,

The inertia runs are meant to help us optimize the optimizer. Our optimizer has a few free parameters we can tune. We are trying to tune them for our unique parameter surface so that we can have our runs converge in a reasonable amount of time.

As for some taking longer than others, that is more a sim parameter issue. The time step is dependent on the simulation parameters. Some of the inertia runs may be exploring our parameter space more than others so they encounter simulation parameters that lead to a longer/shorter run time.
ID: 64571 · Rating: 0 · rate: Rate + / Rate - Report as offensive     Reply Quote
ProfileRandi
Avatar

Send message
Joined: 18 Feb 11
Posts: 1
Credit: 689,399
RAC: 352
500 thousand credit badge8 year member badge
Message 64581 - Posted: 28 May 2016, 6:26:43 UTC

My task, ps_nbody_5_3_16_v160_1_inertia_p95_1461261003_1288901_1, has run for 10 hours and is at 9% with 4 days to go. However, the deadline is 10 hours from now.
Is there any point in continuing it, or should I abort it and let another task run?
Thanks!
ID: 64581 · Rating: 0 · rate: Rate + / Rate - Report as offensive     Reply Quote
Svenxx

Send message
Joined: 20 Feb 16
Posts: 1
Credit: 2,159,537
RAC: 0
2 million credit badge3 year member badge
Message 64589 - Posted: 29 May 2016, 8:41:50 UTC

Hi,

Since N-Body 1.60 I've had an significant increase in tasks which ended in "Error while computing"

This is one of the examples:
ID: 64589 · Rating: 0 · rate: Rate + / Rate - Report as offensive     Reply Quote

Message boards : News : Nbody Release 1.60

©2019 Astroinformatics Group