Ok so now where can I test a huge prime besides gimps
 

I used mprint5c and it printed a very large number, I don't wish to wait a year or so at gimps rather a few hours. So do you guys know if I can test super large primes online or is there other software say mprinttestprime?

[QUOTE=ONeil;485548]I used mprint5c and it printed a very large number, I don't wish to wait a year or so at gimps rather a few hours. So do you guys know if I can test super large primes online or is there other software say mprinttestprime?[/QUOTE]For Mersenne numbers Prime95/mprime is the fastest available software for your CPU. If you have a GPU or are running more complex hardware, there are other options.

You are barking up the wrong tree.

Why do you want different software? And in what range are you planning on checking?

I don't know why no one suggested Pari-GP (offline).
Download, setup, get the LL test code from the net or write your own and test your numbers.
Keep in mind that in the range you have hinted at, you will have to wait for days if not longer for the test to complete.

[QUOTE=a1call;485553]I don't know why no one suggested Pari-GP (offline).
Download, setup, get the LL test code from the net or write your own and test your numbers.
Keep in mind that in the range you have hinted at, you will have to wait for days if not longer for the test to complete.[/QUOTE]

Can you time 100 iterations of LL using PARI/GP for a random-sized input at ~43 million bits?

[QUOTE=ONeil;485548]I used mprint5c and it printed a very large number, I don't wish to wait a year or so at gimps rather a few hours. So do you guys know if I can test super large primes online or is there other software say mprinttestprime?[/QUOTE]

The fastest way I know of for someone with your knowledge to find out a number is not prime is to claim you've found a new prime, include the number, and wait a few hours for someone to tell you why you are wrong.

[QUOTE=paulunderwood;485555]Can you time 100 iterations of LL using PARI/GP for a random-sized input at ~43 million bits?[/QUOTE]

No, have no clue. I know it will be huge.
Will GIMPS be significantly faster?

[QUOTE=a1call;485557]No, have no clue. I know it will be huge.
Will GIMPS be significantly faster?[/QUOTE]

[CODE]? allocatemem(100000000)
*** Warning: new stack size = 100000000 (95.367 Mbytes).
? p=nextprime(43000000);n=2^p-1;s=Mod(random(n),n);print(gettime());for(k=1,100,s=s^2-2);print(gettime())
4
100656
[/CODE]

1 second per iteration, which is 43 million seconds or roughly 500 days. For sure, we can do better modular reductions. Call it 200 days. On a single core of a 4770k how long does it take using Prime95?

Before testing for primality, look for small primes that are factors.

After that use pfgw, which can take the decimal string and PRP test it. It uses the gwnum library (the math behind Prime95), but will likely take a long time to run since the number isn't of any special form (that we know of). But it is likely that it will only be a PRP and cannot be proven prime.

[QUOTE=paulunderwood;485558][CODE]? allocatemem(100000000)
*** Warning: new stack size = 100000000 (95.367 Mbytes).
? p=nextprime(43000000);n=2^p-1;s=Mod(random(n),n);print(gettime());for(k=1,100,s=s^2-2);print(gettime())
4
100656
[/CODE]

1 second per iteration, which is 43 million seconds or roughly 500 days. For sure, we can do better modular reductions. Call it 200 days. On a single core of 4770k how long does it take using Prime95?[/QUOTE]
I have never used prime95, so kindly answer your question.:smile:

[QUOTE=a1call;485561]I have never used prime95, so kindly answer your question.:smile:[/QUOTE]

I don't know. Maybe 7 days. Of course the leading edge of tests is now much bigger!

[QUOTE=rogue;485560]Before testing for primality, look for small primes that are factors.
[/QUOTE]
Thank you for posting the only non-cryptic and insightful reply to the OP.
And in case the OP is unaware, the factors of 2^p-1 will be of the form 2kp+1 (correct?) which should speed up the finding of the factors.