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drummers-lowrise
1) Message boards : News : State of the validator after the challenge (Message 32469)
Posted 3551 days ago by shoelace
is the challenge cleanup finished?
should we change to longer work units now?

would that help the validator catchup?
2) Message boards : General discussion : Question about electricity (Message 32025)
Posted 3557 days ago by shoelace

forgot. we pay $.11 a KWhr here. so much higher electricity costs.


some comparisons power prices.

Montreal, Canada.. $0.04/kwh (canadian dollars)
Melbourne, Australia $0.20/kwh (australian dollars)

3) Message boards : Problems and Help : New BOINC Wrapper needed for Windows LLR (Message 31511)
Posted 3566 days ago by shoelace
no.. sorry.. i wasnt able to get the sample to compile.. successfully..

stupid thing.. i migt huninstall and try using VS2008 if i can still find it for download. (instead of vs2010)
4) Message boards : Sieving : Factorial/Primorial Sieve Discussion (Message 31479)
Posted 3567 days ago by shoelace
i did say "under 1%" as in "less than 1%"

perahps i shoul dhave been less generaous and say "less then 0.1%"

i seem to rememebr the SOB sieve reduced by that amont.. but possible only when an entire K was eliminated.

5) Message boards : Sieving : Factorial/Primorial Sieve Discussion (Message 31241)
Posted 3571 days ago by shoelace
yes.. the factor found are removd from the sieve file.

i believe candidiates that have been LLR'd already are removed too. (not sure on that)

and yes it _usually_ make the sieve faster.. but only very small amounts ( under 1%)
6) Message boards : General discussion : Running boinc on a comp with no internet connectivity (Message 30891)
Posted 3578 days ago by shoelace
prpnet migth work well..

run on internet computer to fill buffers (set to largish size)

stop run

transfer folders to non net machine (via usb key or something)

run on non net machine (possibel straight off usb key)

stop and tranfer back..

rinse and repeat.

7) Message boards : Project Staging Area : January's PRPNet Challenge Project on GFN (Message 30705)
Posted 3581 days ago by shoelace
if we could get GPU seiveing for GFN numbers, that migth make further sieving worthwhile..

without knowing how long seiveing takes
i'd suggest more cpu sieving may not be worthwhile.
8) Message boards : Project Staging Area : Sierpinski/Riesel Base 5 Project (Message 30702)
Posted 3581 days ago by shoelace
maybe "daily history" might be better then
9) Message boards : Sieving : Newbie Question - Sieving based on primorial patterns and symmetry (Message 30526)
Posted 3584 days ago by shoelace

Take a look at 131# (aka p(32)#): 525896479052627740771371797072411912900610967452630. The largest HDD can only store about 1000000000000 bytes of data. It should be easy to see that storing the pattern for that primorial is not physically possible.


thanks rogues.. yes that nicely illustrates why we can't sieve infinitely deep.


Pete, covering sets can be read about here.. http://en.wikipedia.org/wiki/Covering_set

but on re-reading it i dont think that applies here.
10) Message boards : Sieving : Newbie Question - Sieving based on primorial patterns and symmetry (Message 30446)
Posted 3585 days ago by shoelace
Pete,

are you in fact sugegsting to follow your method continuously, and not do teh second step of "check the 'small' primes jst found against the (much much) larger candidate numbers"?

if so, the yes that is essentially "equivalent of the sieve of Erathosthenes" with a few shortcuts.
some shutcust that are already used include:
using bits to repersent odd numbers only (ie all multiples of 2 are completely ignored)
and covering sets (which might be closed to what you are suggesting)

i think a modern computer will still run out of ram/storage before being able to complete a sieve to a depth of the size you are suggesting.
(maybe rogue can comment on this.)

Cheers
shoelace


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