Select Code to Download

v1 * w1 + v2 * w2 + v3 * w3 + ... + vn * wn

  V * W
---------   = cos ( theta )
...
  VV * WW     VV * WW 
----------- = ------- = cos( theta )
|VV| * |WW|    1 * 1

$v = [ 1, 4, 7, 10, 13,  16, 19, 22 ];
$w = [ 1, 2, 4, 8, 16 ];

...
my $dot_product = dot_prod( $v, $w ) or die( "dot_prod error" );;
my $denom = (norm( $v ) * norm( $w );
my $cos_theta = $denom ? $dot_product / $denom : 0;