Optimal depth?

[vjs]

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We are probably no where near 5% of the total projects resources spent on sieve. If we have spent 1% of our computational effort thus far on sieve I'd amazed.

[Matt]

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We are probably no where near 5% of the total projects resources spent on sieve. If we have spent 1% of our computational effort thus far on sieve I'd amazed.

Are you considering the contribution of PrimeGrid to sieving? They have added a significant boost to the sieve effort. Do we have any figures to compare?

[engracio]

Are you considering the contribution of PrimeGrid to sieving? They have added a significant boost to the sieve effort. Do we have any figures to compare?

Ya vjs, got any figures or is that just your best wag?

I would not consider Primegrid contribution not significant. Individual contribution previous to Primegrid were definitely less than 1% compare to prp individual contributions. Primegrid changes that.

[vjs]

A bit of a wag LOL...

But I took some offense to axn's post. ( sorry to point a finger directly that's not my intent).

As a reality check: sieving from 25P to 200P will eliminate roughly 1-ln(25P)/ln(200P) = 5.2% candidates only. So as a rule of thumb, no more than 5% of resource should be spent in sieving.

So as a reality check could someone run some numbers for me.

1-ln(50P)/ln(200P) =
1-ln(100P)/ln(200P) =
1-ln(150P)/ln(200P) =



and

1-ln(400T)/ln(1P) =
1-ln(500T)/ln(1P) =
1-ln(400T)/ln(600T) =




Also as to

: Prime Grid

[Bananaman42]

So as a reality check could someone run some numbers for me.

1-ln(50P)/ln(200P) =
1-ln(100P)/ln(200P) =
1-ln(150P)/ln(200P) =



and

1-ln(400T)/ln(1P) =
1-ln(500T)/ln(1P) =
1-ln(400T)/ln(600T) =

1-ln(50P)/ln(200P) = 0.0348
1-ln(100P)/ln(200P) = 0.0174
1-ln(150P)/ln(200P) = 0.0072

1-ln(400T)/ln(1P) = 0.0265
1-ln(500T)/ln(1P) = 0.0201
1-ln(400T)/ln(600T) = 0.0119

The above results are rounded to 4 decimal places.

[vjs]

1-ln(400T)/ln(600T) = 0.0119

So if we currently sieved to 400T and were thinking about sieving to 600T we should only devote <3% of our total resources? Just checking... on the logic.

[Freeze_XJ]

I can see the logic of all the logaritms, but i prefer a faster way to calculate efficiency :
Right now i'm popping out a factor a day or so when sieving, and a full PRP-test takes about a month or more. (running 4core, so should correct for that... let's say a week) That means that sieving is about 7 times as efficient as is, so i'll continue sieving :P

@vjs : just a bit more than 1% of total resources... and probably not worth the effort... But hey, we're not even close yet Once sieving reaches 50T we reevaluate, can always switch, but it'd be much better if the PRP-ers switch to us first