Measuring weight for a word on a page

Code for calculation weight for a word in its context on a page. This code is from Sphider project.

<?php
// Relative weight of a word in the title of a webpage
$title_weight  = 20;

// Relative weight of a word in the domain name
$domain_weight = 60;

// Relative weight of a word in the path name
$path_weight    = 10;

// Relative weight of a word in meta_keywords
$meta_weight    = 5;


function
calc_weight ($words_in_page, $word_in_title, $word_in_domain, $word_in_path, $path_depth, $meta_keyword) {
   global
$title_weight, $domain_weight, $path_weight,$meta_weight;
  
  
$weight = ($words_in_page + $word_in_title * $title_weight +
             
$word_in_domain * $domain_weight +
             
$word_in_path * $path_weight + $meta_keyword * $meta_weight) *10 / (0.8 +0.2*$path_depth);
  
   return
$weight;
}
?>

Source: Sphider project http://www.sphider.eu/

Knowledge keywords: