[QUOTE=pinhodecarlos;461712]
Back to the topic, you can run only two cores, it won't generate a lot of heating and it will be safe to do it.[/QUOTE]

Another alternative is reduce the TDP of my cpu.

Hello,

I'd like to help on the project, but I'm afraid I'm not 100% certain how to proceed.

In particular I'm not sure how to start the C version of the program. Let's assume I pick 4000-4001. Should I run it this way?
[code]./gap -n1 4000000000000000000 -n2 4001000000000000000 -gap 1000 -delta 196 -sb 25 -bs 14 -mem 4 -t 8[/code]For reporting what minimum gap should I use? The default is 1346 which seems too high.

[QUOTE=ldesnogu;461746]Hello,

I'd like to help on the project, but I'm afraid I'm not 100% certain how to proceed.

In particular I'm not sure how to start the C version of the program. Let's assume I pick 4000-4001. Should I run it this way?
[code]./gap -n1 4000000000000000000 -n2 4001000000000000000 -gap 1000 -delta 196 -sb 25 -bs 14 -mem 4 -t 8[/code]For reporting what minimum gap should I use? The default is 1346 which seems too high.[/QUOTE]

I'm not a person who uses c. You will need to compile the version. There are various compiler script lines mentioned in the thread. In doing so you need to know your computer processor architecture, For example my Intel processor has Haswell architecture.

Maybe the best thing to do is to post what processor you are using and one of the hardware experts here can tell you the best compile script to use.

As far as settings are concerned, it is a matter of taste. I am not the expert on this, but you can use -gap 1346 safely knowing you will pick up all gaps equal or larger than this, and many gaps over 1000 will be reported (but not all). According to your computer's memory size, -sb, -bs and -mem can also be adjusted. I have 8 RAM and I use -sb 24 -bs 13 -mem 5.6. If your computer will not be used for anything else then -t8 is OK for a 4 core computer. -t4 for a 2 core. If you use the computer for work etc., you can scale back to -t4 and -t2 respectively.

Latest stats:

[CODE]

Searcher done resd

Thomas11 159 61
danaj 182 39
antonio 86 25
robert44444uk 79 19
pinhodecarlos 34 31
ET_ 7 0
mart_r 13 10
henryzz 1 9

Total 561 194


[/CODE]

[QUOTE=ldesnogu;461746]
In particular I'm not sure how to start the C version of the program. Let's assume I pick 4000-4001. Should I run it this way?
[code]./gap -n1 4000000000000000000 -n2 4001000000000000000 -gap 1000 -delta 196 -sb 25 -bs 14 -mem 4 -t 8[/code]For reporting what minimum gap should I use? The default is 1346 which seems too high.[/QUOTE]

You could safely run it using the following settings:
[CODE]./gap -n1 4.000e18 -n2 4.001e18 -gap 1250 -delta 155 -sb 24 -bs 16 -mem 4.0 -t 8[/CODE]

Depending on your actual amount of memory, this could be reduced down to 2.05.

I suggest to perform a few test runs to get the optimal settings for you particular system, by using a much smaller interval, e.g.:
[CODE]./gap -n1 4.000e18 -n2 4.000001e18 -gap 1250 -delta 155 -sb 24 -bs 16 -mem 2.05 -t 4[/CODE]

Watch for output lines containing something like "20.33e9 n/sec." and try to improve it by changing your settings.

Edit: Note that there is an internal parameter ([I]default_report_gap = 1000[/I]) which controls the output. The [I]gap[/I] given at the command line is more or less a performance parameter. In practice it means that you may miss a few gaps between [I]default_reporting_gap[/I] and [I]gap[/I].
Thus, with the settings given above you will find [I]all[/I] gaps above 1250 and [I]most[/I] of the gaps above 1000.

Thomas and Robert, thanks for your help!

Last question: how long should it take to sieve a range when I get about 15.04e9 n/sec? About 1 day?

[QUOTE=ldesnogu;461756]Thomas and Robert, thanks for your help!

Last question: how long should it take to sieve a range when I get about 15.04e9 n/sec? About 1 day?[/QUOTE]

Yes, somewhat less than a day. It takes me 2,3 days with 6.1e9 n/sec,

[QUOTE=ldesnogu;461756]
Last question: how long should it take to sieve a range when I get about 15.04e9 n/sec? About 1 day?[/QUOTE]

It's easily computed as: 1.0e15 / 15.04e9 = 66489 sec = 18.5 hours

[QUOTE=ldesnogu;461756]Thomas and Robert, thanks for your help!

Last question: how long should it take to sieve a range when I get about 15.04e9 n/sec? About 1 day?[/QUOTE]

Don't forget to reserve a range - see posts #1 and #3 for the available ranges. I suggest taking no more than 5 consecutive ranges at first to see how you get on.

[QUOTE=Thomas11;461758]It's easily computed as: 1.0e15 / 15.04e9 = 66489 sec = 18.5 hours[/QUOTE]

If you use your computer for other tasks (like I did), YMMV...

[QUOTE=Thomas11;461758]It's easily computed as: 1.0e15 / 15.04e9 = 66489 sec = 18.5 hours[/QUOTE]
That's what I did, I just wanted to be sure the output of the program was meaningful :smile:

Again thanks all for your help.