GPU Trial Factoring FAQ

[firejuggler]

A new low-level API developed by AMD/ATI named Mantle will hit the market soon.
It is essentially a Graphic API, but allow direct access to GPU memory, and can speed up OpenCL. Do you think that can help mfaktco in any way?

[bayanne]

When I go into Manual Assignment for a batch of exponents to check, I am only given those which are for testing from 2^70 to 2^71

Is there a setting on mfaktc.ini which will allow me to pick up exponents at 2^68 or 2^69 onwards?

I am also sometimes receiving the following message when I request an exponent:

Error code: 40
Error text: No assignment available meeting CPU, program code and work preference requirements, cpu_id: 1463, cpu # = 0, user_id = 64

What does this signify please?

[kladner]

Interesting. I just did a test in the PrimeNet manual assignments for TF, and got an 81M from 70 to 71. I don't usually go that route. I use GPU72. There are Double Check TFs available in the 40M range there starting at 68.
http://www.gpu72.com/reports/available/

The thing is, lower bit levels are in demand. They run in less time and each level has the same odds of finding factors. Higher levels = more work to find a factor.

I usually think of Error 40 as a Result not Needed (a duplicate submission.) Apparently, it can also refer to a request for which the parameters given do not find any available assignments.

[bayanne]

I thought I would try the gpu72 route, test reserved 5 exponents in the 64M range. I then checked exponent status on PrimeNet and found that they had been assigned to someone else on 2013-02-19. I then unreserved them.

Is there not a linkage between gpu72 and PrimeNet?

I don't want to poach someone else's exponent ...

[kladner]

Originally Posted by bayanne

I thought I would try the gpu72 route, test reserved 5 exponents in the 64M range. I then checked exponent status on PrimeNet and found that they had been assigned to someone else on 2013-02-19. I then unreserved them.

Is there not a linkage between gpu72 and PrimeNet?

I don't want to poach someone else's exponent ...

GPU72 gets its assignments from PrimeNet. What user was indicated when you saw that the exponents were already assigned? I am seeing "Trial factoring to "GPU Factoring" on 2013-07-24" on one of my ~63M assignments. In general, GPU72 assignments only show up as "yours" when you complete and report them.

You may have encountered some glitch. Chalsall would have to let you know on that one when he gets a chance.

[bayanne]

Originally Posted by kladner

GPU72 gets its assignments from PrimeNet. What user was indicated when you saw that the exponents were already assigned? I am seeing "Trial factoring to "GPU Factoring" on 2013-07-24" on one of my ~63M assignments. In general, GPU72 assignments only show up as "yours" when you complete and report them.

You may have encountered some glitch. Chalsall would have to let you know on that one when he gets a chance.

This was one allocated to GPU Factoring

[chalsall]

Originally Posted by bayanne

This was one allocated to GPU Factoring

Yes -- that's GPU72's Spider's Account.

How this works is GPU72 reserves candidates from Primenet, and then "lends" them out to workers. The worker (read: you) submits the results to Primenet, where you get the credit.

A few minutes later another GPU72 spider will notice you've completed the work on Primenet, and will give you credit on GPU72. It will then assign the candidate to another person for additional work (if needed), or else release it back to Primenet for LLing assignment.

[bayanne]

Originally Posted by chalsall

Yes -- that's GPU72's Spider's Account.

How this works is GPU72 reserves candidates from Primenet, and then "lends" them out to workers. The worker (read: you) submits the results to Primenet, where you get the credit.

A few minutes later another GPU72 spider will notice you've completed the work on Primenet, and will give you credit on GPU72. It will then assign the candidate to another person for additional work (if needed), or else release it back to Primenet for LLing assignment.

Yes, that's all how it seems to have gone.
I'll take a larger batch this time

[chalsall]

Originally Posted by bayanne

I'll take a larger batch this time

Excellent. Thanks.

Welcome to the party!

[bayanne]

When I change my Mac, it will be likely that there will be the potential to use a eGPU box, such as Blackmagic using Radeon Pro 580 graphics processor with 8GB DDR5 memory.
However does anyone know if any of the software packages can use this to do trial factoring?

Alternatively I can obtain a eGPU unit such as the AkiTio Node Pro fitted with one of the new Turing NVIDIA cards. However I understand tha NVIDIA drivers have not yet been approved by Apple, so not sure what will be the best option.

I have mfaktc running fine on my 4 year old iMac ...

[kriesel]

Originally Posted by bayanne

When I change my Mac, it will be likely that there will be the potential to use a eGPU box, such as Blackmagic using Radeon Pro 580 graphics processor with 8GB DDR5 memory.
However does anyone know if any of the software packages can use this to do trial factoring?

Alternatively I can obtain a eGPU unit such as the AkiTio Node Pro fitted with one of the new Turing NVIDIA cards. However I understand tha NVIDIA drivers have not yet been approved by Apple, so not sure what will be the best option.

I have mfaktc running fine on my 4 year old iMac ...

I don't see a lot of posts on the forum by Mac users running GIMPS software, but it's not zero either. As I recall, there are some running gpu applications. Since you're considering a Radeon, the candidate for tf there is mfakto. I think you'll need to do a compile yourself. Let us know how it turns out. I maintain a reference table of GIMPS software versus hardware, among other reference material; see the attachment on post 2 in https://www.mersenneforum.org/showthread.php?t=23371. The more information you could provide about what works on Mac, the more I can add to make it easier for the next person.