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Thread: Greetings from Portugal!

  1. #21
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    Re: Greetings from Portugal!

    I'll be quoting NFS@Home administrator with a few explanations about the goal of this Boinc Project.

    The goal of NFS@Home is to factor large numbers using the Number Field Sieve algorithm. After setting up two polynomials and various parameters, the project participants "sieve" the polynomials to find values of two variables, called "relations," such that the values of both polynomials are completely factored. Each workunit finds a small number of relations, typically a bit less than 2,000, and returns them. Once these are returned, I combine all of the relations together into one large file then start the "postprocessing." The postprocessing involves combining primes from the relations to eliminate as many as possible, constructing a matrix from those remaining, solving this matrix, then performing square roots of the products of the relations indicated by the solutions to the matrix. The end result is the factors of the number. Currently, we are factoring about one number each week. All factors are linked from the status page.

    For a (much) more technical description of the NFS, see the Wikipedia article or Briggs' Master's thesis.
    My interest lies in the continued development of open source, publicly available tools for large integer factorization. Over the past couple of years, the capability of open source tools, in particular the lattice sieve of the GGNFS suite and the program msieve, have dramatically improved. My collaborators and I have factored quite a few large numbers using these tools.

    Integer factorization is interesting both mathematical and practical perspectives. Mathematically, for instance, the calculation of multiplicative functions in number theory for a particular number require the factors of the number. Likewise, the integer factorization of particular numbers can aid in the proof that an associated number is prime. Practically, many public key algorithms, including the RSA algorithm, rely on the fact that the publicly available modulus cannot be factored. If it is factored, the private key can be easily calculated. Until quite recently, RSA-512, which uses a 512-bit modulus (155 digits), was used. As recently demonstrated by factoring the Texas Instruments calculator keys, these are no longer secure.

    For most recent large factorizations, the work has been done primarily by large clusters at universities. There are two other public efforts, NFSNet and MersenneForum, in both of which I have participated, but the software used by NFSNet doesn't incorporate the latest developments and participation in the MersenneForum effort requires manual reservation and submission of work. I have been toying with the idea of trying a BOINC project for a while now to make it easy for the public to participate in state-of-the-art factorizations, and I found the time to do so. My interest in this project is to see how far we can push the envelope and perhaps become competitive with the larger university projects running on clusters, and perhaps even collaborating on a really large factorization.

    The numbers are chosen from the Cunningham project. The project is named after Allan Joseph Champneys Cunningham, who published the first version of the factor tables together with Herbert J. Woodall in 1925. This project is one of the oldest continuously ongoing projects in computational number theory, and is currently maintained by Sam Wagstaff at Purdue University. The third edition of the book, published by the American Mathematical Society in 2002, is available as a free download. All results obtained since the publication of the third edition are available on the Cunningham project website.

    Concerning target size, I started out somewhat "small" (small meaning that I can do it on our cluster in a few days), but it also took the contributors to this project only a few days as well. For our second project, I chose a target somewhat larger. I will continue to slowly increase the size. The real limit is the memory requirement. The current project requires a bit less than 512 MB of memory. As the size of the target increases, that will also increase somewhat. I will be keeping a close eye on that as we move forward.
    One of the goals of the project is to collaborate with other groups on record-size factorizations.
    Thanks to recent advances in the msieve postprocessing code, a significant barrier limiting the size of numbers that we can factor has been removed. Therefore, over the next few months, we will be factoring progressively larger numbers using the lasievef application. To reflect the increased importance of these larger work units, their credit has been adjusted.

    If your computer has at least 1.25 GB of memory per core and you are not running other memory-hungry applications in the background, please try disabling the lasievee application in your NFS@Home preferences. If your computer can successfully run the lasievef application, you will contribute to the largest NFS factorizations completed to date using open source software and will earn more credits per day. In the case of a quad-core computer with 4 GB of memory, you will earn more credit per day running three instances of lasievef and leaving one core idle than running four instances of lasievee.

    Do not worry if your computer does not have sufficient memory for the lasievef application or other background processes prevent you from using it. Work for lasievee will continue to be available over the long term.

  2. #22
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    Re: Greetings from Portugal!

    Applications available (sievers available) from http://escatter11.fullerton.edu/nfs/...ubset=project:

    lasieved - app for RSALS subproject, uses less than 0.5 GB memory: yes or no
    lasievee - work nearly always available, uses up to 0.5 GB memory: yes or no
    lasievef - used for huge factorizations, uses up to 1 GB memory: yes or no
    lasieve5f - used for huge factorizations, uses up to 1 GB memory: yes or no

    Credit per wu?

    lasieved - 36
    lasievee - 44
    lasievef - 65
    lasieve5f - 65

    Why the difference in credits?
    The more valuable calculation gets more credit. Especially for 16e (lasievef+lasieve5f), the extra credit also awards for the large memory usage.
    What project uses what application?

    lasieved - Oddperfect, n^n+(n+1)^(n+1), Fibonacci, Lucas, Cunningham, Cullen and Woodall for SNFS difficulty below 250.
    lasievee - Cunningham, Oddperfect or other for SNFS difficulty above 250 to ~280.
    lasievef - push the state of art for very difficulty factorizations, above SNFS difficulty of 280
    lasieve5f - push the state of art for very difficulty factorizations, above SNFS difficulty of 280

    The limits depends upon the boundaries chosen for the poly and characteristics of the number being factored. It's advanced math related.

  3. #23
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    Re: Greetings from Portugal!

    Carlos

    Yes, I was not completely correct, I am sorry Carlos Pinho. You never said that the factorization would be cure for cancer. The study of factorization give the mathematical tools to the investigation of genetics. And genetics maybe connected to some types of cancer.

    Sorry for the fact that I am not a scientist and that doesn't help very much either. My understanding is to help making things easier for us the common people to understand things better.

    Thanks for crunching for the team at NFS, your daily output is very nice. NFS is quite a difficult project in credits. I am paying more attention to NFS and it seems that in a short time we could climb some positions at the Project. Pity that we are so involved for the moment in other projects.

    Ricardo Ferreira
    Friends are like diamonds and diamonds are forever



  4. #24
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    Re: Greetings from Portugal!

    Carlos I am very happy that you decided to be a team member.


    Welcome to our team



    Friends are like diamonds and diamonds are forever



  5. #25
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    Re: Greetings from Portugal!

    Quote Originally Posted by pinhodecarlos View Post
    Applications available (sievers available) from http://escatter11.fullerton.edu/nfs/...ubset=project:

    lasieved - app for RSALS subproject, uses less than 0.5 GB memory: yes or no
    lasievee - work nearly always available, uses up to 0.5 GB memory: yes or no
    lasievef - used for huge factorizations, uses up to 1 GB memory: yes or no
    lasieve5f - used for huge factorizations, uses up to 1 GB memory: yes or no

    Credit per wu?

    lasieved - 36
    lasievee - 44
    lasievef - 65
    lasieve5f - 65

    Why the difference in credits?

    What project uses what application?

    lasieved - Oddperfect, n^n+(n+1)^(n+1), Fibonacci, Lucas, Cunningham, Cullen and Woodall for SNFS difficulty below 250.
    lasievee - Cunningham, Oddperfect or other for SNFS difficulty above 250 to ~280.
    lasievef - push the state of art for very difficulty factorizations, above SNFS difficulty of 280
    lasieve5f - push the state of art for very difficulty factorizations, above SNFS difficulty of 280

    The limits depends upon the boundaries chosen for the poly and characteristics of the number being factored. It's advanced math related.

    Great to have you here Carlos and thank you for joining us.

    Great info on this project. One question, how long does it take to complete a work unit from the different projects on an I7? If you have that data available, if not I'll crunch some and post it.

    If you can post this in the NFS forum we'll make it a Sticky for all to view and understand.



  6. #26
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    Re: Greetings from Portugal!

    Thank you for the welcome.

  7. #27
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    Re: Greetings from Portugal!

    Just noticed that Mumps [MM] moved a few cores to NFS@Home. Just a quick note about how to manage the highest credits.
    If you have less than 4 GB of memory it's better to run 3 threads of lasieve5f or lasievef and leave the last thread to another project in case you will be running NFS on a quad machine.
    If more than 2GB of memory available per thread you should always choose lasieve5f or lasievef as the siever application.

    Carlos

  8. #28
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    Re: Greetings from Portugal!

    Quote Originally Posted by Mike029 View Post

    Great info on this project. One question, how long does it take to complete a work unit from the different projects on an I7? If you have that data available, if not I'll crunch some and post it.
    Depends on the position of the Q range you are sieving, as you get closer to the end it goes harder and slower, and also depends on the size of the wu. Example, I am using lasieved on my core i5 750 @3.4Ghz (linux 64 bits) and wu are sized "-c 16000 special q" and they are taking ~1900 secs. This wu only gets me 36 credits.
    I think you should do a test on an i7 for lasievef or lasieve5f. Another way to see how fast are machines is to search for the top computers and if computers as not hidden then you can check the timings for the wu's. The only issue is that you can't check if the processor is overclocked or not. The lasievef or lasieve5f applications have sized of 1000 special q.

    Warning: only run this project if you have linux 64 bits, no windows because the applications are 70 % slower. They are not optimized for windows. Example, my T7250 @ 2.00GHz windows laptop is taking ~13,000 seconds to do a wu.

    [quote]Q range: Sieving range, indicating the total number of workunits, each one managing 16k Q values[quote]

    Carlos

  9. #29
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    Re: Greetings from Portugal!

    Carlos

    I think that those who can will crunch a bit NFS. We have not a good position at the project and that can be rectified at least for 3 or 4 places up.

    Mumps, well Mumps is Mumps he is like the cookie monster instead of eating cookies he crunches CPU tasks. Thanks for the help Mumps.



    Carlos we are waiting for your and NFS Administrators to give us some more detailed explanation on the project.

    Do as Mike said start a new thread at our Forum NFS. People will have questions of course.

    We are here in case you need any help with the articles. I am always around but jumping from one task to another.
    I promise to make a lot of confusion with the articles. This way we all learn what is really in there.

    Your friend
    Ric
    Last edited by Duke of Buckingham; 09-19-12 at 09:42 AM.
    Friends are like diamonds and diamonds are forever



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