Yafu

[swellman]

FWIW this happens on several of my machines. I’ve never hunted down what causes it but so far no problems. The behavior does seem related to line length, e.g. when the ETA drops a digit the behavior stops. Mostly...

[storm5510]

This is a fascinating program, once I learned to use it. There is one simple thing lacking. Regardless of what you run, you get "ans = x." It would be nice if this were added to the session.log file. As far as I can tell, this is not recorded anywhere, and I cannot find a way to do it.

[EdH]

Originally Posted by storm5510

This is a fascinating program, once I learned to use it. There is one simple thing lacking. Regardless of what you run, you get "ans = x." It would be nice if this were added to the session.log file. As far as I can tell, this is not recorded anywhere, and I cannot find a way to do it.

You do realize the factors are in factor.log, yes? You can use:

 cat factor.log >> session.log

to add the whole factor.log file to the end of session.log, or:

cat factor.log | egrep -i 'factor|prp' >> session.log

to add just the lines with factors, or you can further parse the lines with factors to modify the factor lines.

[bsquared]

Originally Posted by EdH

You do realize the factors are in factor.log, yes? You can use:

 cat factor.log >> session.log

to add the whole factor.log file to the end of session.log, or:

cat factor.log | egrep -i 'factor|prp' >> session.log

to add just the lines with factors, or you can further parse the lines with factors to modify the factor lines.

If what he is after is factors then yeah, these and other ways work. I'm sure that's what 99.99% of people that use yafu are after. But if one is running in interactive mode, using it as a bigint calculator or whatever, then all of the "answers" disappear once they scroll out of your window buffer. Storm's suggestion would indeed be nice in that case.

Although it seems the wip version of yafu has lost the ability to record interactive sessions... I'll have to look into that.

[storm5510]

Originally Posted by bsquared

If what he is after is factors then yeah, these and other ways work. I'm sure that's what 99.99% of people that use yafu are after. But if one is running in interactive mode, using it as a bigint calculator or whatever, then all of the "answers" disappear once they scroll out of your window buffer. Storm's suggestion would indeed be nice in that case.

Although it seems the wip version of yafu has lost the ability to record interactive sessions... I'll have to look into that.

This was just a passing thought, and for the benefit of others who use it far more than I do.

Off-topic, a little. At the bottom of the readme file, there is a suggestion to run a factor on a huge number.

factor(2056802480868100646375721251575555494408897387375737955882170045672576386016591560879707933101909539325829251496440620798637813)

I thought to myself that this might take a while. I was astonished when it took less than 30 seconds.

[bsquared]

Originally Posted by storm5510

This was just a passing thought, and for the benefit of others who use it far more than I do.

Off-topic, a little. At the bottom of the readme file, there is a suggestion to run a factor on a huge number.
I thought to myself that this might take a while. I was astonished when it took less than 30 seconds.

Thanks! That number was carefully constructed so that factor's various methods (rho, pm1, ecm) all are able chip away pieces of it, thus enabling QS to quickly finish it off. It highlights what "factor" was designed to do, and is relatively good at.

[storm5510]

Originally Posted by bsquared

Thanks! That number was carefully constructed so that factor's various methods (rho, pm1, ecm) all are able chip away pieces of it, thus enabling QS to quickly finish it off. It highlights what "factor" was designed to do, and is relatively good at.

You're welcome!

Below is something you may be able to help me with. I gave it a factor to do in the form commonly used here, 2^p-1. It seems to drop out too soon. Perhaps, I need to format this expression differently if I want it to go farther?

It also says something about no tune info. I ran it as described in docfile.txt It must not be looking in the right place.

Finally, there is a large file called YAFU, with not file extension. What is it?

[VictordeHolland]

Originally Posted by storm5510

Below is something you may be able to help me with. I gave it a factor to do in the form commonly used here, 2^p-1. It seems to drop out too soon. Perhaps, I need to format this expression differently if I want it to go farther?it?

You're giving YAFU a number with millions of digits, it is not designed to handle such big numbers.

[LaurV]

Actually not. He is giving yafu a number of 9 digits (295598220), which yafu factors promptly, properly, and correctly. That is because the caret in windows has a special signification, and it is purged out by the powershell from the command line. You need to add between one and 4 carets (depending of what you want). I have somewhere a post about this.

However, assuming the expression would be passed to yafu right, it would still not work, because of what Victor said, yafu is designed to factor numbers of few hundred digits maximum, and its best use is to factor aliquots, or other stuff under 200 digits.

[storm5510]

Originally Posted by VictordeHolland

You're giving YAFU a number with millions of digits, it is not designed to handle such big numbers.

This is all I needed to know. Thank you!

[MisterBitcoin]

Originally Posted by LaurV

Actually not. He is giving yafu a number of 9 digits (295598220), which yafu factors promptly, properly, and correctly. That is because the caret in windows has a special signification, and it is purged out by the powershell from the command line. You need to add between one and 4 carets (depending of what you want). I have somewhere a post about this.

However, assuming the expression would be passed to yafu right, it would still not work, because of what Victor said, yafu is designed to factor numbers of few hundred digits maximum, and its best use is to factor aliquots, or other stuff under 200 digits.

I can recommend to use an file to input numbers into yafu..
Just use

factor(n)

in a file. I use "n.in" as file name. You only need to use

yafu.exe < n.in

in PowerShell or CMD. (Windows)

About max. digits. It depends on your system (I would guess so), talking of me:
Windows 10, medium notebook

Max 1500 digits for special form numbers like m^n+/-1. Numbers without short expression will only work up to ~1300 digits; over that value I´ll get an error.

My Linux Server:
Anything under 10,4K digits works fine; not tested any higher values; no needs.