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Message boards : Number crunching : Calculation of BS-rac.

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Profile Leendert
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Credit: 1,769,142
RAC: 0
Message 27486 - Posted: 24 Mar 2007, 19:42:25 UTC

Boinctats.com calcultates/gives the credits, rank and BS-rac. I looked in the faq\'s and forums for the calculation of the BS-rac, but could not find it.
Could someone explain?
Thx.

Profile MikeMarsUK
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Message 27487 - Posted: 24 Mar 2007, 20:19:35 UTC



RAC is a decaying average. After a month or so, it\'ll be roughly similar to the average work done per day. Different sites use different decay formulae and decay periods - BoincStats has a longer period than most so takes longer to increase (and also longer to decrease).
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Profile Saenger
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Message 27493 - Posted: 25 Mar 2007, 9:05:38 UTC

Willy calculates his own RAC, mainly because some projects don\'t let the RAC decrease the RAC for crunchers that stopped crunching.

I\'ve asked him several times as well to write the calculation method in the FAQ, I don\'t know why he hasn\'t done so. But I expect it to be close to the official method, only calculated once a day and not with every granted credit.

This will give a higher RAC for projects that grant dayly every few hours, and a faster decaying RAC for projects with grants every few days.

Official formula:

So how is the Recent Average Credit computed? Each time new Credit granted, the following function is used to update the Recent Average Credit of the Computer, Participant, or Team:

RAC(new) = RAC(old)*d(t) + (1-d(t))*credit(new)

Where d(t) is the decay function, and t is the time (in seconds) since the last Recent Average Credit recalculation.

d(t) = e^(-ln(2)*t / 604800)

The Recent Average Credit for any Computer, Participant, or Team is calculated every time that Credit is added to that object. Please see also the example on the right.

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For questions about Boinc look in the BOINC-Wiki

Profile MikeMarsUK
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Message 27498 - Posted: 25 Mar 2007, 10:24:51 UTC
Last modified: 25 Mar 2007, 10:25:49 UTC

While we\'re on the subject, does anyone know where netstats-online get their credit figures from? It matches up with the figures on the bottom of the \'your account\' pages on some of the more recently-updated projects, but doesn\'t seem to tally up with reality.


For example, this particular account which is the subject of a bit of a storm at the moment shows credit from CPDN on netsoft, but none in the actual account it links to:

http://boinc.netsoft-online.com/get_user.php?cpid=76db680ba32bbff7599ce4aa12d06341&html=1

http://climateapps2.oucs.ox.ac.uk/cpdnboinc/show_user.php?userid=188887

But the Boinc project list on the \'your account\' page also matches netsoft. Curiously it\'s obviously wrong on this page since the official Rosetta credit is 0, but the list immediately below shows a figure.
http://boinc.bakerlab.org/rosetta/show_user.php?userid=86037

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David Ball
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Message 27554 - Posted: 27 Mar 2007, 15:25:24 UTC - in response to Message 27493.

Willy calculates his own RAC, mainly because some projects don\'t let the RAC decrease the RAC for crunchers that stopped crunching.


Thanks for posting that Saenger. I had been trying to figure out why the points matched but the RAC was different. IIRC, the Rank is different also.

Thanks,

-- David

Profile Saenger
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Message 27608 - Posted: 28 Mar 2007, 21:01:09 UTC - in response to Message 27554.

Willy calculates his own RAC, mainly because some projects don\'t let the RAC decrease the RAC for crunchers that stopped crunching.


Thanks for posting that Saenger. I had been trying to figure out why the points matched but the RAC was different. IIRC, the Rank is different also.

Thanks,

-- David


I just got the \"official\" answer from Willy in his forum:
Quick \'simple\' answer:

Gained credit over the past x days divided by x

where x is the number of days in the day-history used for the 60 day history chart, with a maximum of 60 days.


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For questions about Boinc look in the BOINC-Wiki

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