Viewing a prime?

mmkstarr · 2019-10-14, 22:11

Is there a way to view the prime in decimal form that is trying to be calculated?
Michael

ATH · 2019-10-14, 22:56

There is this very old program but it still works in Windows 10 command prompt:
http://www.apfloat.org/apfloat/mprintc5.zip

If you want to print the full number of the exponent you are working on, lets say 2^90000049-1, just run in the command prompt:
mprint.exe 90000049 10 > 90000049.txt

and it will be written to the file 90000049.txt, it took 9 sec on 1-core of my 4 year old Haswell-E. The number 10 is the base (decimal) but you can change that between 2 and 36.

mmkstarr · 2019-10-14, 22:58

Thanks, I got it. I just didn't know what the prime # was and the formula.

What I did was actually plug in 2**(M)-1 into python. It's chugging as we speak.

Many thanks!

ATH · 2019-10-14, 23:55

You will not get a result in Python unless you add some arbitrary precision library like GMP or MPIR:
https://gmplib.org/
http://mpir.org/

These numbers are millions of digits long and no "normal" programming language has variables that can handle them.

mmkstarr · 2019-10-15, 00:25

Ah, okay. That explains why, hours later, it's not done yet.

I'll look into your advices.

Thanks.

pepi37 · 2019-10-15, 20:08

WIN PFGW64
pfgw -od -lname.txt -qnumber you tested

example

pfgw -od -lquasi-repdigit-k9.txt -q9*10^380734+1

mmkstarr · 2019-10-15, 20:08

The python crunch was successful but the DOS window clipped the result -_-.

hansl · 2019-10-15, 20:48

mmkstarr, you might be interested in learning PARI/GP, its a very fast general calculator/scripting language and good with large integers. It uses GMP internally.

Using ATH's example of 2^90000049-1, you can output to a file very easily with a single command:

Code:

write("M90000049.txt", 2^90000049-1)

Takes about 8.5s on my computer, to write a 27,092,716 digit decimal number to the file.

Just keep in mind if you write to the same file twice it will append the next output, not overwrite from scratch, so don't accidentally append more than one result to the same file.

There's also even a subforum here for it, if you want to learn more: https://mersenneforum.org/forumdisplay.php?f=155

CRGreathouse · 2019-10-16, 02:32

PARI/GP is a good language for messing around with big (or not so big) numbers like that. Stop by the forum if you want help, or alternatively join the mailing list (not a part of mersenneforum).

2019-10-14, 22:11	#1
mmkstarr Oct 2019 2² Posts	Viewing a prime? Is there a way to view the prime in decimal form that is trying to be calculated? Michael

2019-10-14, 22:56	#2
ATH Einyen Dec 2003 Denmark 2×1,579 Posts	There is this very old program but it still works in Windows 10 command prompt: http://www.apfloat.org/apfloat/mprintc5.zip If you want to print the full number of the exponent you are working on, lets say 2^90000049-1, just run in the command prompt: mprint.exe 90000049 10 > 90000049.txt and it will be written to the file 90000049.txt, it took 9 sec on 1-core of my 4 year old Haswell-E. The number 10 is the base (decimal) but you can change that between 2 and 36. Last fiddled with by ATH on 2019-10-14 at 22:58

2019-10-15, 20:08	#6
pepi37 Dec 2011 After milion nines:) 1,451 Posts	WIN PFGW64 pfgw -od -lname.txt -qnumber you tested example pfgw -od -lquasi-repdigit-k9.txt -q910^380734+1 Last fiddled with by pepi37 on 2019-10-15 at 20:08*

2019-10-15, 20:48	#8
hansl Apr 2019 5×41 Posts	mmkstarr, you might be interested in learning PARI/GP, its a very fast general calculator/scripting language and good with large integers. It uses GMP internally. Using ATH's example of 2^90000049-1, you can output to a file very easily with a single command: Code: write("M90000049.txt", 2^90000049-1) Takes about 8.5s on my computer, to write a 27,092,716 digit decimal number to the file. Just keep in mind if you write to the same file twice it will append the next output, not overwrite from scratch, so don't accidentally append more than one result to the same file. There's also even a subforum here for it, if you want to learn more: https://mersenneforum.org/forumdisplay.php?f=155

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2019-10-14, 22:58	#3
mmkstarr Oct 2019 4₈ Posts	Thanks, I got it. I just didn't know what the prime # was and the formula. What I did was actually plug in 2**(M)-1 into python. It's chugging as we speak. Many thanks!

2019-10-14, 23:55	#4
ATH Einyen Dec 2003 Denmark 2×1,579 Posts	You will not get a result in Python unless you add some arbitrary precision library like GMP or MPIR: https://gmplib.org/ http://mpir.org/ These numbers are millions of digits long and no "normal" programming language has variables that can handle them.

2019-10-15, 00:25	#5
mmkstarr Oct 2019 2² Posts	Ah, okay. That explains why, hours later, it's not done yet. I'll look into your advices. Thanks.

2019-10-16, 02:32	#9
CRGreathouse Aug 2006 3·1,993 Posts	PARI/GP is a good language for messing around with big (or not so big) numbers like that. Stop by the forum if you want help, or alternatively join the mailing list (not a part of mersenneforum).