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Rechenkuenstler
Rechenkuenstler
Joined: 22 Aug 10
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RE: RE: RE: AFAIK

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AFAIK Primegrid requires double precision support in its GPU version, which not all graphic cards offer.

nope they don't..


I just read it in their Web page. They list 3 nVidia cards which can do double-precsion math:
GTX260-295,400,500
Tullio

Correct: I have a GTX460 in one of m machines and this does double precision. All NVIDIA cards with FERMI architecture do

Richard Haselgrove
Richard Haselgrove
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But why on earth would they

But why on earth would they need double precision (i.e. floating point hardware) to do integer maths?

joe areeda
joe areeda
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RE: But why on earth would

Quote:
But why on earth would they need double precision (i.e. floating point hardware) to do integer maths?


The video cards use FP for 3D rendering. OpenGL is full of matrix transforms and transcendental functions. While the results are integer very little else is.

tullio
tullio
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I had the same feeling. But

I had the same feeling. But since I don't know PrimeGrid enough to reason about it I just stuck to their Web page. Certainly Eratosthenes' sieve does not need floating point math. But perhaps the use the Riemann's conjecture.
Tullio

Grutte Pier [Wa Oars]~MAB The Frisian
Grutte Pier [Wa...
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RE: I had the same feeling.

Quote:
I had the same feeling. But since I don't know PrimeGrid enough to reason about it I just stuck to their Web page. Certainly Eratosthenes' sieve does not need floating point math. But perhaps the use the Riemann's conjecture.
Tullio

Crunched the Proth Prime Search (Sieve)CUDA WU's on 2 Fermi-cards but cannot remember having false results.

tullio
tullio
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RE: Crunched the Proth

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Crunched the Proth Prime Search (Sieve)CUDA WU's on 2 Fermi-cards but cannot remember having false results.


Which is the quorum? On QMC quorum is 1 and so in AQUA and CPDN, since they all use the MonteCarlo algorithm.
Tullio

Grutte Pier [Wa Oars]~MAB The Frisian
Grutte Pier [Wa...
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RE: RE: Crunched the

Quote:
Quote:

Crunched the Proth Prime Search (Sieve)CUDA WU's on 2 Fermi-cards but cannot remember having false results.

Which is the quorum? On QMC quorum is 1 and so in AQUA and CPDN, since they all use the MonteCarlo algorithm.
Tullio

For PPSS it was 2.

Allen Clifford
Allen Clifford
Joined: 24 Aug 10
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RE: RE: The cross

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The cross validation problems are being looked at quite actively at present.

Cheers, Mike.

As Mike already pointed out, we're looking into this.

Thanks for your patience,

Oliver

Thank you for letting us know that you have seen these problems.

Good luck on finding a fix, or at the very least finding out what is causing this.

Oliver Behnke
Oliver Behnke
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RE: Thank you for letting

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Thank you for letting us know that you have seen these problems.

Well, not exactly. Our tests didn't exhibit these accuracy issues and they do occur only on a certain fraction of systems. The volunteer computing landscape is vastly heterogeneous so things like this can escape even a thorough testing phase.

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Good luck on finding a fix, or at the very least finding out what is causing this.

We know which things have an impact on this and we'll be working on a fix very soon. However, we might depend on your feedback in order to verify that those fixes indeed improved the situation since we probably can't test/reproduce the observed behavior using our own test systems.

Thanks,
Oliver

Einstein@Home Project

tullio
tullio
Joined: 22 Jan 05
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When I worked in the

When I worked in the Honeywell-Bull UNIX marketing, the computers that had survived all inhouse testing were immediately brought down by users who did the wrong things that test engineers had not even imagined.
Tullio

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