Operation Megabit Twin - Page 12

amphoria · 2010-08-13, 09:32

20T-40T complete to p=45T.

http://www.sendspace.com/file/a2hnsb

Flatlander · 2010-08-13, 10:26

60T-80T is complete. Just in time for the rally at NPLB

http://www.sendspace.com/file/ntnc0r

Merfighters · 2010-09-01, 14:08

I think NewPGen was saving results when the computer suddenly shut down.
After that, it got wrong and printed the results of n=1...

So I'm releasing 100T-120T.
The sieve file (with an error) is on:
http://www.sendspace.com/file/dp0zpe

kar_bon · 2010-09-01, 14:54

Quote:

Originally Posted by Merfighters

I think NewPGen was saving results when the computer suddenly shut down.
After that, it got wrong and printed the results of n=1...

So I'm releasing 100T-120T.

Next time you should use the option "Use two save files"!

Your file is only readable to k=100955363547885, the remaining is empty!

amphoria · 2010-09-01, 18:53

Quote:

Originally Posted by Merfighters

So I'm releasing 100T-120T.

I'll take 100T-120T. It should be finished in 15 days.

amphoria · 2010-09-18, 09:08

100T-120T is complete to p=45T and can downloaded here:

http://www.sendspace.com/file/u52nhx

I have also combined 0-120T together into a single file for the next stage. I had to use 7-Zip to compress the file to get it below the sendspace limit of 300MB, but I created a self-extracting file so you don't need to install 7-Zip. Warning - it is 220MB and uncompresses to 1.75GB!

http://www.sendspace.com/file/aydb2w

Finally I am reserving 45T-50T. It looks like it will take about 12 days on one 2.4GHz core.

Remember to Log Factors Removed for this stage.

Dougal · 2010-09-18, 14:27

how can i change the header on the file?it's too big to open.

amphoria · 2010-09-18, 17:36

Quote:

Originally Posted by Dougal

how can i change the header on the file?it's too big to open.

A very good question which I didn't think of! It is fairly easy under Linux as you could do what I did to create the large file in the first place.

What I will do is upload a new version without a header. Then all you need to do is create a header in a file called header.txt containing a line similar to the following but with the appropriate starting point:

50000000000000:T:0:2:3

Ensure that you press ENTER at the end of the line.

Open a Command prompt and then concatenate the files together with

copy header.txt+0-120T_noheader.txt 0-120T.txt

I have tested this under Windows at it is quick and works.

I will post another message with the link when the upload is complete.

mdettweiler · 2010-09-18, 17:50

Another thing that may be useful: try downloading TextPad for Windows. With it I've been able to open really big files in seconds; 1.75 GB should be within its realm of capability. (I'm not sure whether this will actually require 1.75 GB of RAM, though...I don't think I've ever tried a file that big myself.)

While amphoria's tip is another good way to do this, it is handy to have a text editor on hand that can open big files in case you don't have access to a header-less sieve file.

Also worth checking out is the XVI32 hex editor (not sure of the link but Google should turn it up), as originally recommended for the n=333333 sieve.

TimSorbet · 2010-09-18, 18:34

Would it be possible for a text or hex editor to only open the first x bytes/characters of a large file? Then let you change it, and save it back to the file? Or, similarly, a utility to split the file into manageable chunks, so you can edit it, then recombine them? (preferably allowing you to set different chunk sizes, e.g. put the first 100 bytes in their own file, then the rest in its own)
(if you could do the latter, you could do the former...but it would probably mean the former would be much slower than it might need to be, because it'd write to the hard drive for about twice the size of your unmanageable file)
Does anything like that exist?

kar_bon · 2010-09-18, 19:13

Here's another example to do it:

Create a batch-file called 'SetHead.bat' with following lines:

Code:

@echo off
ren %1 old_sieve.txt
echo %2 >%1
type old_sieve.txt | findstr /C:" " >>%1

Calling 'SetHead <File> <new_Head>' for example
'SetHead 0-120T.txt 50000000000000:T:0:2:3'
will create a new file (with the original name) with that new header line and the old file is renamed 'old_sieve.txt'.

2010-09-18, 18:34	#131
TimSorbet Account Deleted "Tim Sorbera" Aug 2006 San Antonio, TX USA 11·389 Posts	Would it be possible for a text or hex editor to only open the first x bytes/characters of a large file? Then let you change it, and save it back to the file? Or, similarly, a utility to split the file into manageable chunks, so you can edit it, then recombine them? (preferably allowing you to set different chunk sizes, e.g. put the first 100 bytes in their own file, then the rest in its own) (if you could do the latter, you could do the former...but it would probably mean the former would be much slower than it might need to be, because it'd write to the hard drive for about twice the size of your unmanageable file) Does anything like that exist? Last fiddled with by TimSorbet on 2010-09-18 at 18:38

2010-09-18, 19:13	#132
kar_bon Mar 2006 Germany 3062₁₀ Posts	Here's another example to do it: Create a batch-file called 'SetHead.bat' with following lines: Code: @echo off ren %1 old_sieve.txt echo %2 >%1 type old_sieve.txt \| findstr /C:" " >>%1 Calling 'SetHead <File> <new_Head>' for example 'SetHead 0-120T.txt 50000000000000:T:0:2:3' will create a new file (with the original name) with that new header line and the old file is renamed 'old_sieve.txt'.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
The Third Megabit Drive	pinhodecarlos	Riesel Prime Search	145	2023-01-20 11:23
Operation: Billion Digits	clowns789	Operation Billion Digits	575	2023-01-02 18:57
The Second Megabit Drive	Kosmaj	Riesel Prime Search	461	2022-04-10 09:08
modulo operation for polynomials?	smslca	Math	3	2011-04-18 17:18
The modulo operation, how is it computed?	eepiccolo	Math	7	2003-01-08 03:07

2010-08-13, 09:32	#122
amphoria "Dave" Sep 2005 UK 2³·347 Posts	20T-40T complete to p=45T. http://www.sendspace.com/file/a2hnsb

2010-08-13, 10:26	#123
Flatlander I quite division it "Chris" Feb 2005 England 31·67 Posts	60T-80T is complete. Just in time for the rally at NPLB http://www.sendspace.com/file/ntnc0r

2010-09-01, 14:08	#124
Merfighters Mar 2010 On front of my laptop 167₈ Posts	I think NewPGen was saving results when the computer suddenly shut down. After that, it got wrong and printed the results of n=1... So I'm releasing 100T-120T. The sieve file (with an error) is on: http://www.sendspace.com/file/dp0zpe

2010-09-18, 09:08	#127
amphoria "Dave" Sep 2005 UK 2³·347 Posts	100T-120T is complete to p=45T and can downloaded here: http://www.sendspace.com/file/u52nhx I have also combined 0-120T together into a single file for the next stage. I had to use 7-Zip to compress the file to get it below the sendspace limit of 300MB, but I created a self-extracting file so you don't need to install 7-Zip. Warning - it is 220MB and uncompresses to 1.75GB! http://www.sendspace.com/file/aydb2w Finally I am reserving 45T-50T. It looks like it will take about 12 days on one 2.4GHz core. Remember to Log Factors Removed for this stage.

2010-09-18, 14:27	#128
Dougal Jan 2009 Ireland 10111010₂ Posts	how can i change the header on the file?it's too big to open.

2010-09-18, 17:50	#130
mdettweiler A Sunny Moo Aug 2007 USA 6298₁₀ Posts	Another thing that may be useful: try downloading TextPad for Windows. With it I've been able to open really big files in seconds; 1.75 GB should be within its realm of capability. (I'm not sure whether this will actually require 1.75 GB of RAM, though...I don't think I've ever tried a file that big myself.) While amphoria's tip is another good way to do this, it is handy to have a text editor on hand that can open big files in case you don't have access to a header-less sieve file. Also worth checking out is the XVI32 hex editor (not sure of the link but Google should turn it up), as originally recommended for the n=333333 sieve.