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2019-10-25, 00:46   #463
EdH

"Ed Hall"
Dec 2009

3·5·211 Posts

Quote:
 Originally Posted by Dylan14 Hmm... could you try cat cuda.h to see what version it is? If it is larger than 3 (which is most likely is) then you may have to fiddle around with the configure script so it looks for a higher version.
I'll do a cat in a bit (after I recover from an extended power outage - one of the problems with having a bunch of ancient machines, some of which don't wake back up right). Meanwhile, I had tried playing around with some of the code in the configure file in an attempt to swap failure with success, but I wasn't able to get anywhere - I'm a bit too far over my head.

Thanks!

 2019-10-25, 03:09 #464 EdH     "Ed Hall" Dec 2009 Adirondack Mtns 316510 Posts @Dylan14: Good Call! The one I was pointing to was something from last century. I found one in a very current folder that got me a couple steps further. Now I have to work on libraries. But I had to stop for now. Thanks!
 2019-10-26, 01:48 #465 EdH     "Ed Hall" Dec 2009 Adirondack Mtns 3·5·211 Posts This #%$@ thing is fighting me all the way! Last straw!: Code: checking for compatibility between gcc and nvcc... no configure: error: gcc version is not compatible with nvcc Last fiddled with by EdH on 2019-10-26 at 02:15 Reason: I couldn't even spell! Must be tired. . . 2019-10-26, 02:04 #466 chalsall If I May "Chris Halsall" Sep 2002 Barbados 2·3·1,499 Posts Quote:  Originally Posted by EdH This #%$@ think is fighting me all the way!
As is its job.

You're smarter than it is.

Prove it.

2019-10-26, 02:18   #467
EdH

"Ed Hall"
Dec 2009

3×5×211 Posts

Quote:
 Originally Posted by chalsall As is its job. You're smarter than it is. Prove it.
But, I think it is more patient.

However, a bit after I posted, I thought, "I did get further than last night."

2019-10-26, 02:39   #468
chalsall
If I May

"Chris Halsall"
Sep 2002

2×3×1,499 Posts

Quote:
 Originally Posted by EdH However, a bit after I posted, I thought, "I did get further than last night."
And that is exactly how to approach this kind of "problem space".

Run experiments. Observe results.

Repeat as necessary...

Give it a little bit of time, and you'll begin "lucid dreaming" about stuff like this.

It's kinda cool waking up with "well, obviously, that's how you'd do that" before even the first coffee of the morning...

 2019-10-26, 03:17 #469 EdH     "Ed Hall" Dec 2009 Adirondack Mtns 61358 Posts Success! Thanks for the words of encouragement. I'll see if it will repeat tomorrow and figure out where to post here if success is repeatable...
2019-10-26, 15:27   #470
EdH

"Ed Hall"
Dec 2009

316510 Posts

Quote:
 Originally Posted by EdH . . . I'll see if it will repeat tomorrow and figure out where to post here if success is repeatable...
I added it as a new thread to my list of How I... threads in the blog area:

How I Compile the GPU branch of GMP-ECM in a Colaboratory Session

Last fiddled with by EdH on 2019-10-26 at 15:28 Reason: None given

 2019-11-05, 18:51 #471 EdH     "Ed Hall" Dec 2009 Adirondack Mtns 3×5×211 Posts How Valuable Is Stage 1 In the Overall ECM Process This question is based primarily on my playing with Colab and my GPU-GMP-ECM setup mentioned earlier. If I run the GPU version, it will saturate the GPU with as many curves as cores available and run stage 1. But, in a recent test case, that was over 4k cores. If I were to fully process all those it would mean about 30 minutes for the stage 1 part on the GPU (for my chosen number/B1), followed by an awfully long CPU processing time for stage 2 to finish all those runs with only two CPU cores handling them. Is there much value n running just stage 1 ECM, realizing that unless I keep the residues for later followup, all those stage 1 runs will have to be repeated at some point?
2019-11-05, 20:01   #472
fivemack
(loop (#_fork))

Feb 2006
Cambridge, England

18CC16 Posts

Quote:
 Originally Posted by EdH This question is based primarily on my playing with Colab and my GPU-GMP-ECM setup mentioned earlier. If I run the GPU version, it will saturate the GPU with as many curves as cores available and run stage 1. But, in a recent test case, that was over 4k cores. If I were to fully process all those it would mean about 30 minutes for the stage 1 part on the GPU (for my chosen number/B1), followed by an awfully long CPU processing time for stage 2 to finish all those runs with only two CPU cores handling them. Is there much value n running just stage 1 ECM, realizing that unless I keep the residues for later followup, all those stage 1 runs will have to be repeated at some point?
Don't just run stage 1! Keep the residues, they are pretty tiny - less than 500 bytes per curve. Use something like

Code:
ecm -v -v -gpudevice 0 -gpu -save e.$u.s1 85e7 1 then take the .s1 files home, split the lines up however you like and let your other cores at them Code: ecm -maxmem 3000 -resume$u 85e7 < ../N > \$u.s2
Or post the .s1 files somewhere, link to them from this forum and let people at them.

I found it was 43.6 hours to do 1792 stage-1 curves on a GTX1080Ti and about 1070 seconds on one core of Xeon Silver 4114 to run stage 2 on one curve (so you needed about 12 such cores to keep up with the GPU)

Last fiddled with by fivemack on 2019-11-05 at 20:01

 2019-11-05, 20:40 #473 EdH     "Ed Hall" Dec 2009 Adirondack Mtns 3·5·211 Posts Thanks! I must have gotten something mixed up in my earlier testing. (That's happening a lot , lately.) I thought I ran some 11e7 stage 1 tests on a Colab session in about 40 minutes for 832 curves, but I'm coming up on 2 hours this time. I must have been using a smaller candidate before. I will modify my routine to save residues, then and see what other mischief I can come up with. Thanks, again!

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