#!/usr/bin/perl
print "Content-Type: text/html\n\n<pre>\n";
$damp = 0.85;
$a = $b = $c = $d = $e = $f = $g = $h = 0;
$iterate = 40; # loop 40 times
# forward links
# a -> b,c,d - 3 outgoing links - home
# b -> a - 1 outgoing link - about
# c -> a - 1 outgoing link - products
# d -> a,e,f,g,h,i,j,k,l - 9 outgoing links
# e,f,g,h - nothing - external sites
# i -> a - 1 link - review of e
# j -> a - 1 link - review of f
# k -> a - 1 link - review of g
# l -> a - 1 link - review of h
# i.e. "backward" links (what's pointing to me?)
# a <= b,c,d/9,i,j,k,l
# b,c,d <= a/3
# e,f,g,h,i,j,k,l <= d/9
while ($iterate--) {
printf("a: %.5f b: %.5f c: %.5f d: %.5f e=f=g=h: %.5f i=j=k=l: %.5f\n",
$a, $b, $c, $d, $e, $i);
$a = 1 - $damp + $damp * ($b + $c + $d/9 + $i + $j + $k + $l);
$b = $c = $d = 1 - $damp + $damp * ($a/3);
$e = $f = $g = $h = $i = $j = $k = $l = 1 - $damp + $damp * ($d/9);
}
printf("Average pagerank = %.4f\n", ($a + $b + $c + $d + $e*4 + $i*4) / 12);
print("</pre><a href=http://www.ianrogers.net/google-page-rank/#ex4>Back to example 4</a>");
