GIMPS on PS3

[flouran]

Originally Posted by CRGreathouse

LL-NF. If you want to maximize your chance to find a Mersenne prime, you want to search the smallest numbers possible -- larger numbers are both harder to test and less likely to be prime. Further, if you can have someone else do the TF work, that makes your throughput on LL higher.

Joining a team or not doesn't affect your chance to find a Mersenne prime.

I have one computer (which is a Pentium M) doing TF work, and the other two new computers are doing LL (also known as "LL first") work. And then we'll see how it goes with the PS3...

[CRGreathouse]

As starrynte suggests, the PS3 may be good at trial factoring. It's not clear to me because I don't know how memory access works in that architecture.

[flouran]

Originally Posted by CRGreathouse

As starrynte suggests, the PS3 may be good at trial factoring. It's not clear to me because I don't know how memory access works in that architecture.

But trial factoring takes so long compared to LL. I would disagree with starrynte. But, if I can get it to work, I would be more than happy to try both. Can starrynte substantiate his claim?

[flouran]

Originally Posted by starrynte

Also though the Cell may not be able to run LL/DC tests very well, I am interested how it does TF.

How come the Cell may not be able to run LL/DC tests very well? I mean, TF is waaay slower than LL especially for a fast processor like the Cell. Could you perhaps elaborate more on that?

Thanks

[retina]

Originally Posted by flouran

How come the Cell may not be able to run LL/DC tests very well? I mean, TF is waaay slower than LL especially for a fast processor like the Cell. Could you perhaps elaborate more on that?

You can't compare speeds of TF and LL. They are different tests. Apples to oranges. What makes you think the Cell is fast? Compared to what? Just run your tests and give the results. Why so much speculating and talking, just do it!

[CRGreathouse]

Originally Posted by flouran

How come the Cell may not be able to run LL/DC tests very well? I mean, TF is waaay slower than LL especially for a fast processor like the Cell. Could you perhaps elaborate more on that?

I don't know what you mean by "TF is waaay slower than LL".

The Cell is optimized for 16- and 32-bit floating point operations, while LL tests prefer 53, 64, 96, or 128 bits. That means that perhaps 8 to 15 Cell cycles do an amount of work similar to one Core 2 cycle, depending on how you emulate it. But for TF, each cycle should be able to do a similar amount. But TF work should depend largely on how much memory can be accessed quickly, and I don't know how the Cell works in that regard. (I don't own a PS3 or any other gaming console.)

[Uncwilly]

Read these threads (they deal with the subjects that you are talking about):
http://www.mersenneforum.org/showthread.php?t=10275
http://www.mersenneforum.org/showthread.php?t=7627
http://www.mersenneforum.org/showthread.php?t=9741
http://www.mersenneforum.org/showthread.php?t=7918
http://www.mersenneforum.org/showthread.php?t=6880
http://www.mersenneforum.org/showthread.php?t=6627
http://www.mersenneforum.org/showthread.php?t=3686

TF is only to eliminate factors, it is faster complete (to current levels) than LL.

[flouran]

Originally Posted by retina

You can't compare speeds of TF and LL. They are different tests. Apples to oranges. What makes you think the Cell is fast? Compared to what? Just run your tests and give the results. Why so much speculating and talking, just do it!

Ummm.... The Cell is fast, and CRGreathouse's quote substantiates this (you can do more research on it yourself):

Originally Posted by CRGreathouse

I think this is a great idea. All the experts here think it will do poorly, but people keep bringing the idea up -- this should finally get some hard numbers. The PS3 Cell is (I believe) a nominal 3.2 GHz @ 8 cores

Although it may not be REALLY fast, it would be interesting to do it nonetheless.
Furthermore, I am speculating because I will have time this weekend (or the next) to play with my PS3, so results won't come in until then. And besides, anyone with a PS3 is more than welcome to try it.

[flouran]

Originally Posted by Uncwilly

Read these threads (they deal with the subjects that you are talking about):
http://www.mersenneforum.org/showthread.php?t=10275
http://www.mersenneforum.org/showthread.php?t=7627
http://www.mersenneforum.org/showthread.php?t=9741
http://www.mersenneforum.org/showthread.php?t=7918
http://www.mersenneforum.org/showthread.php?t=6880
http://www.mersenneforum.org/showthread.php?t=6627
http://www.mersenneforum.org/showthread.php?t=3686

TF is only to eliminate factors, it is faster complete (to current levels) than LL.

Great work. Thank you very much. I will look at them in more depth this weekend (or whenever I have more time).

[retina]

Originally Posted by flouran

Ummm.... The Cell is fast, and CRGreathouse's quote substantiates this (you can do more research on it yourself):

Okay, then prove it is fast. But fast at what? I suspect you have been reading too much marketing material (aka propaganda).

[flouran]

Originally Posted by retina

Okay, then prove it is fast. But fast at what? I suspect you have been reading too much marketing material (aka propaganda).

haha maybe...
Plus it is a gaming console so it should be fast (as compared to say the current market of the x86 family of processors).