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All the Perl that's Practical to Extract and Report

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  • Cool it looks like I could build a funky vector space search engine using the mysql cosine function.

    Not quite. MySQL has a scalar cosine function, like Perl and damn near every other programming language you can name. Because this is a vector based search engine, you need to take the cosine of the two vectors, as the article clearly states:

    The formula for calculating the cosine is this:

    cos = ( V1 * V2 ) / ||V1|| x ||V2||

    Where V2 and V2 are our vectors, the vertical bars indicate the

    • I guessed it wouldn't be that easy ;)

      That confirms my initial concerns that it wouldn't scale well, as you would have to do a lot of mathematical grunt work in Perl (or more likely the C PDL library), as opposed to using a specialised tool like a relational database to the bulk of the processing.

      I don't think MySQL would manage the cosine math involved here. Oracle probably would using horrid PL/SQL perversions, but that would subtract rather from the initial elegance.

      It would be nice to be able to do


      @JAPH = qw(Hacker Perl Another Just);
      print reverse @JAPH;