[Spambayes] Chi-squared perl port problems

[Tim Peters]

[Matt Sergeant]
>      for my $i (1 .. ($v >> 2)) {

Watch out for that too -- shifting right by 2 isn't dividing by 2, so 
you're systematically getting results (probably way) too small out of 
chi2Q.  The right range here is 1 .. ($v/2-1).

Suggestion:  use chi2.py's showscore() function to show the internal 
Python details on small artificial prob vectors.  Then you can check 
intermediates one-by-one against the Perl version.