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1)
Message boards :
General discussion :
A New Sieve? Or just Smoking my Socks!?!
(Message 151405)
Posted 631 days ago by  SteveRC
After making a new (fully expandable!) spreadsheet and writing a little VB program..
https://drive.google.com/drive/folders/1FajFZiDTw1kbqWBi4PtqNiKKDUmAHpSy?usp=sharing
I have come to the conclusion this approach will probably just amount to sieving out the non-prime exponents when they are fairly big... so maybe not that hugely useful... But interesting nonetheless!
Also quite impressed with this code that calculates the first 1M primes and sieves out the first 10M Mersenne-exponents, which got to about 600k primes sieved while I was asleep last night!
Not bad for a few lines of Windows-forms VB code! - But I'm sure those with their heads more in the Maths (Yves!?!) and some super-efficient C++, could do a MUCH better job!!
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2)
Message boards :
General discussion :
A New Sieve? Or just Smoking my Socks!?!
(Message 151383)
Posted 633 days ago by SteveRC
No idea what yr post has to do with my stuff, Nick! Did u post to the correct thread?
Anyway, here is a slightly better spreadsheet for Docs.. (but still conks out before M(100)!)
But anyway, the important stuff is at the bottom half of the spreadsheet, which has no problems with overflow!!
https://docs.google.com/spreadsheets/d/1jSyORkSbdNUweq6JFybXaUCT3oNugGzW/edit?usp=sharing&ouid=109422053006376628543&rtpof=true&sd=true
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3)
Message boards :
General discussion :
A New Sieve? Or just Smoking my Socks!?!
(Message 151381)
Posted 633 days ago by SteveRC
I was thinking about Mersenne numbers, wondering what a 'trial-division' table of Mersenne numbers divided by Prime numbers (M MOD P) would look like, so I set up a spreadsheet
https://docs.google.com/spreadsheets/d/1-rJiHZZA-pIp9SRloIZ5p9sqhK2h9Pki/edit?usp=sharing&ouid=109422053006376628543&rtpof=true&sd=true
to try visualize it better.. I was amazed to see the remainders in the columns under the primes were all periodic, with periods(Pd) always less than the Prime numbers themselves..
Excel integers can only calc up to M(52) directly, so I changed the formula at this point to allow calc up to M(104) to enable calc of periods of primes up to 101..
I thought at first no two periods would be the same, but primes 23 and 89 both have Mersenne-Periods of 11!
It occurred to me that this 'periodic-nature' would provide a quick and simple way to sieve big Mersenne numbers using 'n' directly, without ever having to calculate, or work with, (2^n-1)...
So I added a second table under the first, but now instead of calculating (M MOD P), we simply calculate (n MOD Pd)-1 and we get the same zeros (marking composites) in the same places as the upper table! But now 'n' can be as large as we like without any overflow problems!
Seems to me it would be child's play to calculate those Mersenne-Periods for the first few hundred-thousand prime numbers,(sorted and with duplicates removed!) then for each P you only need to calc (n MOD Pd) for the first one of an arbitrarily-large block of Mersenne-exponents (starting wherever u like!), and then just go thru the block, 'crossing-out' every Pd'th exponent in standard Eristothanes-fasion!!
Now I'm a Pretty Good Programmer, but a Lousy Mathematician, so I'll leave it up to those who don't just get a headache like me when trying to understand the concepts behind the maths we use to find these numbers, to punch holes, or explain to me why this is not the way we should do it!!
Or perhaps this (or something even faster) is already being done, but takes a lot longer than I think it should!?! (and what about GFN's? Do they exhibit the same properties??)
Edit: Just noticed Google-Docs number-resolution much crappier than the Open-Office spreadsheet I used!! - will post a fixed sheet for Docs shortly..!!
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4)
Message boards :
Number crunching :
GPU overheating
(Message 105136)
Posted 2292 days ago by SteveRC
What you (and all other aspiring Laptop GPU Crunchers) need... is..
TThrottle
This pic shows my Dell Latitude E5570 laptop Tthrottle graph over 12 hours last night..
You can see while GPU sits below 70degC, the CPUs are pushing into the high 80s..
This is because they share the same heatsink, but thermal transfer is much better for the GPU, so it sits much closer to the Heatsink temp.
The graph shows a wealth of interesting information..
- each 'tick'(heartbeat?) on those CPU and GPU lines represents a successfully completed task! :-)
u can see the 'gap' in the readings just before 1am, when Windows rebooted to install updates :-(
After the reboot, temps shot up quite quickly, causing 2 things to happen simultaneously -
1. Tthrottle hit it's CPU temp limit, causing it to throttle the CPU tasks, (the blue DownSpikes!)
2. The Laptop also hit a thermal 'limit', causing a period of 'high-fan-revs'
This results in CPU temp dropping even lower than the usual 'steady' temps we had before midnight.. - but after a while, the laptop decides it's 'cool-enough' and switches its fan off! - causing this cycle to repeat for the next few hours.
Then around 07h30 the hot African Sun makes its appearance, requiring throttling to begin in earnest.. - Note that CPU and GPU hit limit at the same time.. (there is a small GPU throttle downspike!) - but as soon as CPUs are throttled to around 60%, heatsink temp drops and GPU can continue at full throttle!
Then just after 8am, I come in and crank-up the Aircon!
I DO have a nice, big CoolerMaster Laptop fan blasting cool air onto the base, but with that and Tthrottle, there's no reason not to let yr trusty laptop reward you with with many more 'ticks' - and hopefully another Prime before the month is out..!
It's the answer to World(GPU-Thermal)Tension!
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5)
Message boards :
Number crunching :
Badges - Full Sets!
(Message 103281)
Posted 2333 days ago by SteveRC
Thanx to Challenge... All back to Cool Turq..!
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6)
Message boards :
Number crunching :
Help setting up new PC
(Message 102993)
Posted 2338 days ago by SteveRC
I use TightVNC myself. I tried TeamViewer, but if you lose your internet connection you can't connect to the box sitting next to you. That was unacceptable. ...
Not strictly true... Teamviewer works just fine without any internet connection!
If u select [Extras] [Options] from the Teamviewer pulldown menu u will see
[Incoming LAN Connections] under [Network Settings] - which defaults to [Deactivated].
Change this to [Accept] and Teamviewer will happily connect to any local PC without any Internet connection! - simply use the PC's IP address instead of the Teamviewer ID number, and u get a fast, seamless connection with all TeamViewer's cool File-Transfer and Drag&Drop features - regardless of the state of your Internet connection!
TightVNC is fine for 'local' networks, but nothing beats Teamviewer's ability to find it's way thru Corporate Firewalls and suchlike..!!
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7)
Message boards :
Number crunching :
Disturbance
(Message 100762)
Posted 2392 days ago by SteveRC
Look at that prime score he's got - not going to be beaten for a while. Consider it embedded it concrete.
Mr. Brown got chopped down from spot #1 in a single prime. I am sure he will keep hunting for that tops spot again.
In a few days Mr. Brown will be number 3 in the "Top List".
Tell us more! Here is the list top users by score. /JeppeSN
I gues that the wingman will be the second on the list when he finishes the workunit... right?
(he is rocking a AMD A6-3600 APU, so it will take a while)
"She". Very reliable computer on SoBs, but also very slow. Hopefully it will complete the task, but it will take a few weeks.
By my calculation, our wingman(wingwoman?) should come yodeling in from the Swiss Alps around the 3rd of December!
.. perhaps an emailed suggestion to suspend the other 3 tasks to make it safer/faster wouldn't go amiss?
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8)
Message boards :
Number crunching :
Badges - Full Sets!
(Message 96485)
Posted 2525 days ago by SteveRC
Finally managed to turn all those Angry Reds to Serene Cyan. A much more restful colour after that seemingly infinite wait for SOB wingmen!!
.. and I just noticed that 300 mil!! Nice coincidence!
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9)
Message boards :
Number crunching :
Summer Solstice Challenge
(Message 95939)
Posted 2535 days ago by SteveRC
Already submitted a couple of tasks from my (So-Last-Season!) 4690k ... and just popped up in 10th place! ... but not likely to stay there long... wondering whether it was worth staying up till 2am...? U Bet it Was!! :-)
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10)
Message boards :
Number crunching :
Hyper threading and LLR
(Message 88679)
Posted 2795 days ago by SteveRC
... With HT, more circuits seems to be active on die, so temperatures are rising. If you'll occasionally get full load on all cores (esp. on Windows which runs tons of trash when computer is idle), it raises chances of bad calculation, system crash, or overheating.
While this may be true, my gut-feel is that running with HT on, and 'locking' LLR tasks to correct cores with high-priority, will ALWAYS show an improvement (however slight) over simply turning HT off and filling all cores with tasks. Mainly because those 'tons of trash' will force continual swapping of the LLR tasks in and out of the cores (with consequent loss of cache 'continuity'), which have to be shared with HT off, but there will be virtually no swapping of 'locked' LLR tasks with 'free' (HT) cores for all the trash (or sieve tasks!) to play around in.
Clearly there will be a rise in temperatures, but that's merely an indication that the cores are doing more work in less time, and therefore being more efficient!
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