OddPerfect enthusiasts & others: ECM help needed!

[frmky]

NFS@Home is working its way up in difficulty toward a kilobit SNFS. We're at 285 digits now, and in about 1-2 months we will start a 290 digit number. sigma(3^606) = 3,607- is a very attractive number since it's simultaneously an OddPerfect roadblock, Cunningham 5th hole once the 3- extension is added (and 3,563- is finished, which will happen shortly), and a number with no known nontrivial factors. We would appreciate any help the OP community and others can provide. For now, the number needs more ECM. Currently a bit over 1*t55 has been completed, so it needs curves with B1 = 26e7.

The easiest way is to create a file containing the line

(3^607-1)/2

then run the command

ecm -c 10 26e7 < file.txt

Adjust 10 to the number of curves you wish to run. Just report the number of curves you have completed in this thread, and thanks in advance for any help you can provide!

All curves are included in the ECM Server at oddperfect.no-ip.com:8201

Post#     Curves
  4         10
 20         40
 28          4
 36          1
 41         15
 46        224
 49       3100 included in #72
 53        320
 57          3
 72       3508 included in ECM Server
 73       3393 new in ECM Server
 74        240
 75         10
 76        960
 77       6703
 87        883
 89       4594

Including directly reported curves, the ECM Server stands at 23785

including lower ECM curves (13875@43e6 & 18240@11e7), this is 4.90 t55 or 0.96 t60

[Andi47]

Originally Posted by frmky

The easiest way is to create a file containing the line

(3^607-1)/2

then run the command

ecm -nn -c 10 26e7 < file.txt

Adjust 10 to the number of curves you wish to run. Just report the number of curves you have completed in this thread, and thanks in advance for any help you can provide!

I would suggest a command line like

ecm -nn -c 10 26e7 <file.txt >>outputfile.out

with the -nn flag, ecm will run on lowest priority.

">>outputfile.out" redirects the output to an outputfile and thus prevents from data loss when a factor is found and the command line window (or bash window) is accidently closed (or the computer crashes for some reason).

If the PC is short on RAM, the command line flag -maxmem <number of MB to use> can be used. For example, -maxmem 500 uses not more than 500 MB RAM.

I will run a fistful of curves until my next GNFS (from aliquot sequence 10212) takes my ressources for a while.

[mdettweiler]

Originally Posted by Andi47

I would suggest a command line like

ecm -nn -c 10 26e7 <file.txt >>outputfile.out

with the -nn flag, ecm will run on lowest priority.

">>outputfile.out" redirects the output to an outputfile and thus prevents from data loss when a factor is found and the command line window (or bash window) is accidently closed (or the computer crashes for some reason).

Even better, if you're on Linux (or Windows w/Cygwin):

./ecm -nn -c 10 26e7 < file.txt | tee -a outputfile.out

That will send the screen output both to the file outputfile.out and to the screen, which is nicer for checking progress along the way.

Those on Windows without Cygwin can probably get tee in UnxUtils; just place tee.exe in the same directory as ecm.exe (or somewhere on your path, if you prefer).

[debrouxl]

Another way to output both to a file and to the screen:
ecm -nn -c 10 26e7 < file.txt >> outputfile.out &; tail -f outputfile.out
or
echo "(3^607-1)/2" | ecm -nn -c 10 26e7 >> outputfile.out &; tail -f outputfile.out
(CTRL + C to end)

I'm running 10 curves, 1 done so far without finding a factor. I won't repost if these curves run to completion without yielding a factor, so as not to clutter the topic

[Andi47]

P-1: B1=1e9, B2=1e14, no factor.

[Andi47]

Originally Posted by Andi47

I will run a fistful of curves until my next GNFS (from aliquot sequence 10212) takes my ressources for a while.

cancelled / crashed, no single curve finished.

In a windoze environment it seems that it is absolutely necessary to specify -maxmem 1800 (or smaller), even if you have plenty of free memory and you are using Win 64 bit and a 64 bit ECM binary.

(ECM crashed when it tried to use more than ~1.8 GB (or 2 GB??) RAM, and I am pretty sure to have downloaded the 64 bit binary of ecm-6.2.3 (how can I check if this is indeed a 64 bit binary?))

[10metreh]

Originally Posted by Andi47

(ECM crashed when it tried to use more than ~1.8 GB (or 2 GB??) RAM, and I am pretty sure to have downloaded the 64 bit binary of ecm-6.2.3 (how can I check if this is indeed a 64 bit binary?))

Run it (on something smaller so that it will run without crashing), and look in Task Manager. If it shows up as "ecm.exe *32" then it is 32-bit; if it is just "ecm.exe" then it is 64-bit.

[Andi47]

Originally Posted by 10metreh

Run it (on something smaller so that it will run without crashing), and look in Task Manager. If it shows up as "ecm.exe *32" then it is 32-bit; if it is just "ecm.exe" then it is 64-bit.

Thanks. And oops, it seems that something went wrong when I downloaded the binary (maybe I copied it into the wrong directory), as it says that the binary I'm using is 32 bit.

Edit: Just downloaded the 64 bit binary and started a large p-1: it is running happily with a memory useage of 3.3 GB.

[em99010pepe]

Anyone here wants to set up an ecmserver for this number?

[R.D. Silverman]

Originally Posted by frmky

NFS@Home is working its way up in difficulty toward a kilobit SNFS. We're at 285 digits now, and in about 1-2 months we will start a 290 digit number. sigma(3^606) = 3,607- is a very attractive number since it's simultaneously an OddPerfect roadblock, Cunningham 5th hole once the 3- extension is added (and 3,563- is finished, which will happen shortly), and a number with no known nontrivial factors. We would appreciate any help the OP community and others can provide. For now, the number needs more ECM. Currently a bit over 1*t55 has been completed, so it needs curves with B1 = 26e7.

The easiest way is to create a file containing the line

(3^607-1)/2

then run the command

ecm -c 10 26e7 < file.txt

Adjust 10 to the number of curves you wish to run. Just report the number of curves you have completed in this thread, and thanks in advance for any help you can provide!

My personal opinion is that doing a number from the extensions, when
the extensions still have not been officially added to the table is
ridiculous

There are many other suitable numbers, still undone, from the 1st printed
edition of the book. Let's work on finishing them.

[Andi47]

Originally Posted by Andi47

P-1: B1=1e9, B2=1e14, no factor.

extended B2 to 1e15, still no factor.