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Dana Jacobsen

  • About: I've been using Perl since 1991 (4.010 or so). At some point I realized that while I have used many languages, I enjoy using Perl more than any others.
  • Commented on Perl6 Pi and continued fractions
    This is tangentially related as it isn't looking at rationals. I've seen a few places that use something like: Pi(n) that gives n digits of Pi. I added that to the Perl5 ntheory library a couple months ago, though I'm...
  • Posted Partitions of an Integer to Dana Jacobsen

    integer partitions comes up regularly, with multiple threads over the years at PerlMonks, a big chunk of ="http://hop.perl.plover.com/book/pdf/05FromRecursionToItera…

  • Commented on Learning Perl 6 - Find in a Large File
    I was having a similar issue, but on a larger file (32M 64-bit integers, about 120x larger than /usr/share/dict/words on my machine). This is more than I'd like to pull into an array, as it uses 13.5GB of memory. Using...
  • Commented on A comparison of memory use for primality modules
    I had tried adding trial division with no better performance, but that last was the clue. For small sizes, when not using Montgomery math, I have trial division using unsigned ints. This almost halves the time on the AIX/Power7 machine...
  • Commented on A comparison of memory use for primality modules
    Perl 5.21.3 built on AIX 7.1 Power 7, 64-bit. Unfortunately building things on AIX is a PITA -- I gave up trying to get GMP, Math::Pari, or ExtUtils::CppGuess (used by Math::Prime::FastSieve) to work. Measuring memory use is non-obvious for fast-running...
  • Commented on Link to public version control system (GitHub or otherwise)
    Thanks for the reminder. It looks like two modules I updated for CPAN day aren't showing up because I forgot to add the meta-spec entry. I made sure I added the repository, but it seems without that it just tosses...
  • Commented on A comparison of memory use for primality modules
    Brian, that's really a different question. This started out as just a "how much memory is used just to load the module without doing anything" but then I figured I should call a single function. Then figured I may as...
  • Posted A comparison of memory use for primality modules to Dana Jacobsen

    Performance and memory use are two areas of concern for many libraries. to reduce memory use, and bulk88 helped really tweak some of the XS. I thought I'd pick a simple …

  • Commented on Perfect Hashes and faster than memcmp
    Very nice. Thanks for making useful open source software and writing about it....
  • Commented on Classify your RT tickets on CPAN Day!
    First a big thanks for all this blogging. I think it is fantastic that you're doing this! Math::Pari probably needs a co-maintainer with lots of time. So far I don't think anyone qualified has wanted to step up. It's a...
  • Commented on vec is slow, little-endian and limited
    When making my Data::BitStream and Data::BitStream::XS modules I did a bunch of vec() manipulation, including versions using Bit::Vector, strings, and my own XS. In many cases what I found was that often just using string storage was faster than Bit::Vector,...
  • Commented on Give your modules a good SYNOPSIS
    Toby, thank you very much!...
  • Commented on Give your modules a good SYNOPSIS
    Thanks for the reference to Test::Synopsis. Is there an easy way to get it to load feature say? It's unhappy with lots of my examples: "Do you need to predeclare say?" One thing I ended up adding to my test...
  • Commented on Giving up on weekly neoCPANisms
    * Anything that involves fixing existing modules instead of creating more. Could even be weighted by # reverse dependencies or ++'s (so an applied bug fix to a common module would be worth lots of points). * Longest chain of...
  • Commented on Math::Prime::Util, May update
    Nate, if your platform has GMP, then Math::GMPz or Math::GMP are great. Similarly, if you're using the right platform then Math::Int128 is nice. But those modules don't work on lots of machines out there. I am going to do a...
  • Posted Math::Prime::Util, May update to Dana Jacobsen

    Math::Prime::Util 0.41 was released, with new functions (valuation, invmod, vecsum, binomial, forpart), and the usual crop of performance improvements. In particular, primality testing on x86_64 got another big speedup.

  • Posted Fun with binomials to Dana Jacobsen

    I decided to add a binomial(n,k) function to Math::Prime::Util, and found some interesting things while doing it. Overflow detection and mitigation in C and Perl were the first thing. Next was looking at negative arguments, which led to…

  • Posted Math::Prime::Util, April update to Dana Jacobsen

    Math::Prime::Util, and the optional Math::Prime::Util::GMP back end, are a set of modules for number theory in Perl, with a large overlap of functionality with

  • Commented on The CPAN new dist a month contest
    I like these, but I wish we would have as many drives to fix open CPAN issues, especially in core or heavily-used modules. I use a lot of modules that have open defects with submitted patches that just sit there....
  • Commented on The 2013 White Camels
    As someone new to going to YAPC's, I want to also say a big congrats to Wendy, Liz, and the Brasilian Perl community. You deserve the recognition, and I hope you see you this summer!...
  • Commented on Wikipedia linking to CPAN
    From the blog: "[...]it would be also interesting to see subjects in Wikipedia that have implementations in Perl and linking to that implementation." The last time I tried that, someone removed *all* the implementation links claiming "Wikipedia is not a...
  • Commented on Rakudo and NQP Internals Workshop (14/15 Sep)
    Very cool indeed. Wish I could come....
  • Commented on CPAN candidates for adoption
    A suggestion for additional scoring is add a point for modules that are mentioned in the core documentation. Perhaps one for modules that are included in core. This came to mind when wondering why Math::TrulyRandom wasn't on the list. It's...
  • Commented on My Love/Hate Relationship with CPAN Testers
    I love CPAN Testers and try to contribute. I've been thinking about firing up some oddball box for more smoking (it's easy and fast to do yet another x86/gcc/Linux tester, but that's well covered). Having the ability for a tester...
  • Commented on Common reasons a module won't install
    Aristotle, you have a point that for hash-randomization breakage the code was wrong (and was *always* wrong, on every platform), but it is an example where an old module, perhaps not updated in many years, now fails to work. Another...
  • Commented on Common reasons a module won't install
    Perl version too high (obvious topical example is hash randomization, but I've seen this sort of thing as well on really old modules). Broken dependency. Mirod already said it, but it's so common. Incompatible operating system I might generalize to...
  • Commented on Factoring integers in Perl
    For clarification, this is looking at prime factors. A table for modules and prime factors vs. divisors: Module prime factors divisors ------------------ ------------- ----------- Math::Big::Factors factors_wheel - Math::Factor::XS prime_factors factors Math::Factoring factor - Math::Prime::Util factor all_factors Math::Pari factorint divisors Pari...
  • Commented on Site Front Page
    I think it has to be automatic, as some of the people doing it seem to be using cross-posting solutions that will clearly ignore any text suggestions. This has also come up often enough that others who are doing walls...
  • Posted Factoring integers in Perl to Dana Jacobsen

    Recently I've been working on factoring and primality proofs (with certificates) for Math::Prime::Util. I thought I'd give a brief summary and comparison of the modules I know of for factoring integers from Perl.

  • Commented on I love CPANtesters and Travis-CI
    I’ll second this. I love CPANTesters, and thanks to LETO for turning me onto Travis-CI....
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