I'm going to guess that this is a straight transfer of a C program to Perl --

First, you'd using a whole lot of for loops for tracking indexes to arrays:

for (my $i = 0; $i < $number_of_clusters; $i++) { ... }

In Perl, if you're just trying to iterate over a range, you can use the 'foreach' style loop, with the range operator:

for my $i ( 0 .. $number_of_clusters-1 ) { ... }

Even if we were doing this in C, for the type of loops you're dealing with (starting at 0, order of operations doesn't matter), I'd still change the code, to reduce the number of comparisons against non-0 values:

for (i = number_of_clusters; i--; ) { ... }

In some cases, we can use the 'foreach' style loops to eliminate the need for index values, but because you're using them to index multiple arrays within the loop, that's not possible in your case.

...

Another change I might make is in how you deal with undefined values -- if the value must be defined, and can't be 0, (eg, $number_of_clusters), you can use the '||=' operator:

$number_of_clusters ||= 2;

...

The only other thing is in how it's called -- if it were OO, you could inherit from it, and then replace the 'distance' function (or you could have it accept a coderef in for the distance function, if you didn't want to support inheritance), as some people prefer the manhatten distance when they're dealing with clusters:

sub distance {
  my ($vec1,$vec2) = @_;
  my $distance = 0;
  for my $i ( 0 .. (scalar @$vec1)-1 ) {
    $difference += abs( $vec1->[$i] - $vec2->[$i] );
  }
  return $difference;
}

[download]

In reply to Re: RFC: Fuzzy Clustering with Perl by jhourcle
in thread RFC: Fuzzy Clustering with Perl by lin0

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.