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Brian D from Georgia
BAM!ID: 56
Joined: 2006-05-10
Posts: 53
Credits: 13,327,665
World-rank: 41,469

2005-05-12 19:51:56

This should be an easy one to answer for some of you power users as I sure couldn't find the information anywhere. ops: When looking at the "view results" page for any of the Boinc projects, there are two columns for claimed credit and granted credit such as this copy/paste from my S@H account:

claimed granted
credit credit

33.63 29.64
29.33 20.03
0.18 0.13
36.44 36.44
19.42 35.60
45.42 20.98
20.12 23.04
40.53 22.36
45.19 35.36

I have noticed that the granted credit is often lower than the claimed credit. What factors into this and is there any way a user can change a setting or something so that the granted credit is in line with the claimed credit :?: Thanks!
Guest

2005-05-13 09:41:23

Hi Bdahl
Clamed Credit is the amout of credit you system claims for doing the work this is based on the time taken and the number of cpu cycles.

This is different for each project check their message boards for more exact answers.

The Granted credit is the amout of credit you receive after the work unit has been validated. This is the average/highest/lowest of the claimed credit from the different systems that also had that work unit.
eg
Claimed Credit
sys-1 10
sys-2 15
sys-3 12

Granted Credit for all systems using average 37/3 = 12.333
Guest

2005-05-13 16:51:26

[url=http://boinc-doc.net/site-common/glossary/letter-c.php' target='_blank]http://boinc-doc.net/site-common/glossary/letter-c.php[/url]

I hope Willy doent mind....

Claimed Credit
Credit is "Claimed" upon completion of a specific Work Unit. When that Work Unit's results are returned to the Data Server the BOINC Software submits a claim for the amount of credit you should be granted when confirming results are returned by another participant in that project who also processed that same Work Unit.

In the interim period between your claiming credit and the Quorum of Results is established your claimed credit is added to your pending credit list.

In the instance where you are returning a result that confirms another result already returned; some, or all, of your claimed credit will be quickly turned into Total Credit. This does not happen immediately because of the time it takes the back-end systems to perform all of its tasks.

The basic formula for calculating Claimed Credit is:

claimed credit = ([whetstone]+[dhrystone]) * wu_cpu_time_in_sec / 1728000

With my computer EQ-1, I have, for example:

Measured floating point speed 1394.01 million ops/sec
Measured integer speed 2630.73 million ops/sec


-------

Total: 4024.74

Result - "Claimed Credit" Example Einstein@Home
Einstein@Home Result Example

With an Einstein@Home Result having a run time of 37,698.16 seconds (as shown in the example image) we have:

37,698.15625
* 4,024.74000
-----------------
151,725,277.38562
÷ 1,728,000
-----------------
87.80397

Which, when rounded gives the displayed Claimed Credit value 87.80 as expected. Note that there is a more precise value shown on the Result page (in this case it was: 87.8039391846125 for what that is worth).
Result - "Claimed Credit" Example Predictor@Home
Predictor@Home Result Example

With a Predictor@Home Result having a run time of 6,354.078125 seconds (as shown in the example image) we have:

6,354.078125
* 4,024.740000
------------------
25,573,512.372689
÷ 1,728,000
------------------
14.799486

Which, once again, when rounded gives the displayed Claimed Credit value 14.80 as expected. Note that there is a more precise value shown on the Result page (in this case it was: 14.799486326788 again, for what that is worth).

For whatever reason, the two examples came up with a value of "X.80" and that is just an artifact. So, don't read anything into that!
Note:
There is an additional refinement in that the Project can determine and specify the ratio of Floating Point to Integer mathmatics with a fraction that is used to scale the benchmark multipliers, with the variable "a" representing the scaling fraction, gives us:

claimed credit = ( a * whetstone + (1 - a) * dhrystone) * wu_cpu_time_in_sec / 1728000

Granted Credit
This is the amount of credit that will be granted all of the participants that are members of the Quorum of Results created by all of the returned results. Remember, though, that the amount of credit granted is determined by the project policies and therefore the amount of credit that you will be granted may not be the amount that was claimed.

Common rules for determining the amount of credit that is to be granted are:

1. The least of the claimed credit amounts submitted by all of the participants in the Quorum of Results (always true when the quorum is 2 or less).
2. Use the mean (average) of all of the amounts of credit claimed by all of the participants in the Quorum of Results.
3. Remove the highest and lowest values and take the average of the claimed credit values of the remaining results.

Quite simply put, your claimed credit is not the same as the granted credit.


I hope that works for you?
Brian D from Georgia
BAM!ID: 56
Joined: 2006-05-10
Posts: 53
Credits: 13,327,665
World-rank: 41,469

2005-05-14 02:52:29

Thank you kindly cjo9900 and Bishop. That explains it perfectly.

bdahl385


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