Credits & Number Crunching


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Questions and Answers : Getting started : Credits & Number Crunching

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Josh
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Joined: 15 May 99
Posts: 2
Credit: 129,199
RAC: 0
United States
Message 1258202 - Posted: 9 Jul 2012, 21:41:26 UTC

Hey folks.. I haven't been terribly active lately, and this forum is new to me. I was wanting to make a post in the Number Crunching section, but it says I need a "certain" number of credits, but doesn't specify what that "certain" number is. How am I to know how many credits I need?

I've been active off and on since 1999 and have what appears to be 129,000 credits, but I am unable to post in that forum. Is there a FAQ anywhere explaining it? I looked through this forum, but nothing specific applied that I saw.

Thanks!
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Profile Ageless
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Joined: 9 Jun 99
Posts: 12259
Credit: 2,553,611
RAC: 823
Netherlands
Message 1258203 - Posted: 9 Jul 2012, 21:46:26 UTC - in response to Message 1258202.

You need to be actively crunching and have a recent average credit (RAC) of 1 or more to be able to post in any forums outside the Help Desk.
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Jord

Fighting for the correct use of the apostrophe, together with Weird Al Yankovic

Josh
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Joined: 15 May 99
Posts: 2
Credit: 129,199
RAC: 0
United States
Message 1258205 - Posted: 9 Jul 2012, 21:58:40 UTC

Got it, thanks!
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Profile Eric Theriault
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Joined: 7 Aug 12
Posts: 1
Credit: 3,764
RAC: 0
Canada
Message 1268836 - Posted: 8 Aug 2012, 0:45:20 UTC

comment les credit son calculer

John McLeod VII
Volunteer developer
Volunteer tester
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Joined: 15 Jul 99
Posts: 24098
Credit: 517,932
RAC: 146
United States
Message 1268859 - Posted: 8 Aug 2012, 2:10:11 UTC - in response to Message 1268836.

comment les credit son calculer

I apologize for responding in English as my French is non-existent.

Credit is granted for validated results. The order of operations is:

1) Two tasks are created from a Work Unit. These are identical.
2) One of these tasks is sent to computer A.
3) The other of these tasks is sent to computer B. Computer A and B will be different users.
4a) One of the two results is uploaded to the upload server.
5a) This result is reported to the scheduler and recorded in the database.
4b) The other result is uploaded to the upload
5b) The other result is reported to the scheduler and recorded in the database.
6) The two results are compared by a validator.
7) If they are close enough, one of them is selected as the canonical result and recorded in the master database. Credit is granted to all results that are close enough*.
If they are not close enough, a third task is sent out. (Start from step 1 with a single task rather than 2. This will lead to at least 3 results for the validator to compare).
If any task is not reported by deadline send another task starting from step 1 with a single task. This will lead to at least 2 tasks to compare in the validator.

* The definition of close enough is looser if there are three that almost match. This means that it is possible for 2 tasks to be declared to be not close enough but have a third task that allows all 3 to get credit.

The calculation of credit is based on an estimate of the number of floating point operations done.

In conclusion, the key points are that the user has to wait for a while to get credit granted for work done. If you are first to report a task, you will fave to wait for your wingmate to finish their task. And then, even if you are second, you have to wait for the validator to get to your Work Unit for validation. Possibly (one time out of about 20) you will have to wait for a third task to complete.

Waiting for a wingmate can take anything from seconds (rare) to a day or two (common) to weeks (again rare). Of course, if yours is second, you don't have to wait for this.

Waiting for the validator to get to that Work Unit typically takes a second or two, but sometimes can take days or weeks if there is something wrong with the validator. It can take a few hours if it is backed up badly.

Waiting for a third task takes a few hours (rare) to a week or so (common) to a month (rare). Of course, a fourth could be needed...

I hope I answered the correct question.
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Questions and Answers : Getting started : Credits & Number Crunching

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