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drummers-lowrise
1) Message boards : Number crunching : Primeform's pseudoprimes? (Message 24827)
Posted 4422 days ago by Kevin
I was running Pform, looking for some primorial-based primes. After it reached k * 11# +1, I noticed the following message:
378*p(5)#+1 is probable prime! (a = 1871) (digits:6)
Verification failed !? (a = 1889)


The number was 873181, which turned out to be 661 * 1321. I doubt that it is a Pform pseudoprime. I'll run some more tests to either prove or disprove that it is a psedudoprime.
2) Message boards : Proth Prime Search : Lone Proth hunter: (Message 24522)
Posted 4438 days ago by Kevin
Hmm..
Again, use PFGW. You are wasting your time with Proth. Take the output file from NewPGen and pass as the lone parameter to PFGW. It can read NewPGen formatted files.


I have tried this.. But it turns out LLR is many times faster. Albeit for the numbers I am looking for, it seems as if it takes approximately 5 minutes to test for each number. Anyway, this is a big reason why I am continually sieving. To reduce the time needed for the tests. 4 months is an unacceptable timeframe. And, it turns out I can't improve that timeframe by much. Since NewPGen employs progressive trial division for its sieving mechanism, it would take trial division to about 10^41820, which would take about 10^41750 to 10^41800 years to finish off completely. (And that is an estimate that is at least 10 orders of magnitude too generous.) Since a reasonable timeframe can't be reached, stopping now, going to see how long it takes to test.. 116 days.
3) Message boards : Proth Prime Search : Lone Proth hunter: (Message 24520)
Posted 4438 days ago by Kevin
The Prime Pages' article for the applet NewPGen makes the following suggestion:

This program, NewPGen, performs this type of sieving. NewPGen should be used to throw out candidate k's until the rate at which it is removing them exceeds the rate at which Proth.exe can perform a power test. At that point Proth.exe should be used to complete the search, with PMax=0 (as trial factoring has already been performed by NewPGen).


I guessed that the candidates to be tested would be the file that NewPGen generates after sieving. If so, where should the file be located in order for the Proth app to recognize the file and perform power tests? I crated a new directory and stored the Proth app in that directory, in case the file and Proth need a similar or identical directory path. It seems that it cannot open the file. Any tips regarding this?
4) Message boards : Proth Prime Search : Lone Proth hunter: (Message 24518)
Posted 4438 days ago by Kevin
Update: I sieved up to 256B, and it turned out to be insufficient. Based on LLR taking nearly 5 minutes to test an 83641-digit number, it would take 4 months to finish testing. And, who has that kind of time? I certainly don't. Sieving raised to 1.6 * 10^13.
5) Message boards : Proth Prime Search : Lone Proth hunter: (Message 24510)
Posted 4438 days ago by Kevin
Update: The odds of a number in the ranges I selected of being prime is only 19.33% (After sieving for up to about 2 to 4 * 10^10). Must update the ranges, unless sieving actually improves probability.
6) Message boards : Proth Prime Search : Lone Proth hunter: (Message 24507)
Posted 4438 days ago by Kevin
Of course I did. I named it workA.txt.Update: Got the pesky text file. Thanks for the help, all. All I need to do is make in an input in LLR, correct? Update 2: Got LLR working on the candidates that were sieved up to 16 billion. By the way, for sieving: Does it perform either:
1. Ex: Sieve up to 11 --> Eliminate multiples of 2, 3, 5, 7, 11
2. Eliminate only multiples of 11.

Also: Prime found! 9731 * 1296^2600 + 1 (Approx. 8097 digits) + Generalized Proth prime.
Another: 12472 * 1296^2600 + 1 (Approx. 8098 digits)
Also: On the search for a new personal record, Range: 83641 or 83642 decimal digits, breaking the previous personal record by a factor of three. Sieving up to 256B. So far, only 7.3% of the candidates remain. Also, if I do find an 83641-digit prime, it's going to be a prime-numbered amount of digits in length. Tips?
7) Message boards : Proth Prime Search : Lone Proth hunter: (Message 24503)
Posted 4439 days ago by Kevin
A question about NewPGen... where is it that you can find the output file it generates after sieving is finished?
It gives the message: "Output file '<filename>.txt' generated, contains <n>k's"
I then proceed to search for the file, and.. find that it does not exist. It's basically saving the results onto a file that does not exist. This must be fixed.
8) Message boards : Proth Prime Search : Lone Proth hunter: (Message 24494)
Posted 4439 days ago by Kevin
Woah. I didn't notice your post. And, was I correct in assuming 1 digit occupies 8 bits?
9) Message boards : Proth Prime Search : Lone Proth hunter: (Message 24492)
Posted 4439 days ago by Kevin
284 GB?!? How would that ever sum to 284 GB? It's testing 15.625 billion candidates in total. 15.625 billion would sum to.. only about 10-20 GB, if I remember correctly. Although I do not have any text editor willing to store 20 GB of digits. (Update: Assuming 8 bits/digit, 15625000000 digits would sum to 125000000000 bits. 125000000000 bits = 15625000000 bytes, assuming 8 bits = 1 byte. 1024 bytes = 1 KB, so 15258789.0625 KB, and 1024 KB = 1 MB, That would be 14901.1611 MB, and 1024 MB = 1 GB, so that would be 14.55191 GB, assuming only one character per line. Multiply the figure by about 14 (The average amount of characters in my ranges, that would be 203.7268 GB.
10) Message boards : Proth Prime Search : Lone Proth hunter: (Message 24490)
Posted 4439 days ago by Kevin
Hmm.. You can't get it to test a range.. So I have to manually list all candidates myself. Using an advanced text editor, this will be relatively simple. I guess a few extra seconds to a minute of work beforehand isn't too much work. Concerning the prime tests to use: I'll set up an experiment to see whether N-1 or PRP works faster. The command I use? I simply use the filename itself. To get to work on setting up my ranges:
k * p(n)#^x + 1, where k is between.. 6250 and 31250; n is between 250 and 1250; x is between 1 and 625. The digit range: 4382 to 2738750.


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