[QUOTE=drh;264573]Looking at the [FONT=Tahoma][SIZE=4][FONT=Verdana][SIZE=2]PrimeNet Activity Summary page, it appears that the best I could probably do is one of the 1421 available TF's in the 58M range. If I can get one of those, would you be interested?[/SIZE][/FONT][/SIZE][/FONT][/QUOTE]Thanks, but no thanks!

To LL 58M now goes completely against my "reasoning" in post #135.

I expect to be assigned another ~ 45M test at 0145 UTC.

I'm sure if you TFed it you could get credit manually, although
ATM it seems that Primenet doesn't appreciate mfaktc or GPUs yet.

I feel (as I expect you do) that more user-friendliness would increase
participation in GIMPS.

David

[QUOTE=davieddy;264580]Thanks, but no thanks!

To LL 58M now goes completely against my "reasoning" in post #135.

I expect to be assigned another ~ 45M test at 0145 UTC.

I'm sure if you TFed it you could get credit manually, although
ATM it seems that Primenet doesn't appreciate mfaktc or GPUs yet.

I feel (as I expect you do) that more user-friendliness would increase
participation in GIMPS.

David[/QUOTE]

Totally understand, and agree. Do you know if it's possible to get credit without an assignment? I always request an assignment first, when I do my manual work.

Thanks,
Doug

From another thread here, regarding axon, it seems the server is rather liberal about granting credit for work that wasn't assigned, no worry there....

Do you need another exponent TF'ed? I have a reasonably fast GPU that I'm willing to ask to extend the TF range, though it may be busy for the next 20-30 hours on a little job for the Billion Digit folks....and it may take six hour for me to read your reply....I'll just feed it a manual assignment. I can PM the result, as well as report it to the server.

Note that the odds of my finding a factor aren't good at a high bit level, but I don't mind trying.

8 hours to go on that piece of the "little" job...I'm willing to insert a TF command to execute at that point.

OK: Take 2
 

M45705851 TFed to 68 bits. B1=480000 B2=4080000.

Further TF welcome. If the two of you are willing to do
5 more bits, the fairest division of labour is 68-72 and 72-73.

I'm afraid the P-1 reduces the expectation of a factor from 5/68
to more like 5%.

I've got 5 hours to go before I can start to LL it, but don't panic:smile:

David

PS Not going to risk "releasing" it this time!

Factor=0,45705851,68,72
Begins in 4 hours on my GTX 440.
This isn't the fastest GPU in the world....just the best my slightly undersized power supply for my AMD Phenom II x6 can support. When i get up in 7-8 hours, I'll report how it's going. It's 23:43 local (E coast US) time, which I think is GMT+5.

[QUOTE=Christenson;264617]It's 23:43 local (E coast US) time, which I think is GMT+5.[/QUOTE]This time of year, it's GMT-4. When not in Daylight Savings Time, we're GMT-5.

Great to have a concrete case to discuss
 

[QUOTE=Christenson;264617]Factor=0,45705851,68,72
Begins in 4 hours on my GTX 440.
This isn't the fastest GPU in the world....just the best my slightly undersized power supply for my AMD Phenom II x6 can support. When i get up in 7-8 hours, I'll report how it's going. It's 23:43 local (E coast US) time, which I think is GMT+5.[/QUOTE]
Message received at 04:44 BST = 03:44 GMT(UTC)

My best iteration times are pretty close to those of 2GHz day/day.
(Celeron440 @2Ghz).

I would estimate that it would take it over a day
to TF 68-69. I await news of your progress with interest!

BTW Prime95 says the probability of being prime is 1/378756,
but I'm not sure whether this takes P-1 into account. George?

Each 1% improvement in these odds converts to a larger incentive
for folk to take on [B]and finish[/B] LL tests!

4 extra bits of TF should make our Mexponent the single most
likely to be prime. Poaching excepted.

David

[QUOTE=davieddy;264636]BTW Prime95 says the probability of being prime is 1/378756,
but I'm not sure whether this takes P-1 into account. George?[/QUOTE]

If it does at all, it could only be in roughest terms, since Prime95 doesn't keep track of what bounds were used in P-1 when you doublecheck/LL, just a 0 for "not-done" and a 1 for "done". So if it was done with generous bounds, you can expect it to be significantly more likely to be prime than stated.

From my "results.txt":
no factor for M45705851 from 2^68 to 2^69 [mfaktc 0.17 barrett79_mul32]
no factor for M45705851 from 2^69 to 2^70 [mfaktc 0.17 barrett79_mul32]
no factor for M45705851 from 2^70 to 2^71 [mfaktc 0.17 barrett79_mul32]

From my "worktodo.txt":
Factor=0,45705851,71,72
Factor=0,45705851,72,73

From my console, just a few minutes before this post:
no factor for M45705851 from 2^70 to 2^71 [mfaktc 0.17 barrett79_mul32]
tf(): total time spent: 2h 45m 42.719s

tf(45705851, 71, 72, ...);
k_min = 25830207618600
k_max = 51660415237314
Using GPU kernel "barrett79_mul32"
......
class | candidates | time | avg. rate | SievePrimes | ETA | avg. wait
193/4620 | 1.12G | 22.696s | 49.43M/s | 56419 | 5h47m | 234us


From my calculations:
5 factor candidates at ~70 bits =~ 5/70 = 1/14 chance of finding a factor, thus saving you the LL testing. Cost of test will be ~20 hours, for about 30GHz days credit. This improves your odds of having M48 insignificantly, from miniscule to miniscule.
Mersenne-aries.sili.net tells us:
73.3GHz days for the LL (so 146.6 days work will need to be done if no factor is found)
40.5Ghz days for TF(68,73).
The classical calculaton says we are well above optimum TF for GHz-Days granted, even ignoring any P-1. An argument could be made for TF to 74 bits, assuming my GPU effort for a GHz-Day is 1/10th the effort of a CPU GHz-day. (This is based on the idea that it is a mid-range card. Someone who has a top-end card could carry out another 2-3 bits for the same wall-calendar effort.)

Many thanks
 

[QUOTE=Christenson;264641]
From my calculations:
5 factor candidates at ~70 bits =~ 5/70 = 1/14 chance of finding a factor, thus saving you the LL testing. Cost of test will be ~20 hours, for about 30GHz days credit. This improves your odds of having M48 insignificantly, from miniscule to miniscule.[/QUOTE]

From [B]my[/B] calculations:
Ignoring P-1 (see Minigeek's post) and assuming
that the probability of finding one or more factors between
2^X and 2^(X+1) is 1/X:

Probability of no factor between 2^X and 2^(X+1) is (X-1)/X.
Probability of no factor between 2^68 and 2^73 is 67/72.

oldminiscule = 1/378756 = 67/72 * newminiscule

newminiscule = 1/352454

Us toilers derive encouragement from such things:smile:

David

[QUOTE=davieddy;264648]Probability of no factor between 2^X and 2^(X+1) is (X-1)/X.[/QUOTE]

[TEX]\sum{k((x-1)/x)} [/TEX] where k is 2^(x-original x) should give the value between any 2 x then no ?