Remove d_o and d_e, unlike in kappa, they have no meaning

Also, Wikipedia shows half values, as the table is symmetrical around
its diagonal, but the ratio stays the same.

Author: choroba

lib/Statistics/Krippendorff.pm

@@ -43,26 +43,20 @@ has _expected   => (is => 'lazy',
                     builder => '_build_expected');
 
 sub alpha($self) {
-    my $alpha = 1 - $self->d_o / $self->d_e;
-    return $alpha
-}
-
-sub d_o($self) {
-    return sum(map {
+    my $d_o = sum(map {
         my $v = $_;
         map {
             $self->coincidence->{$v}{$_} * $self->delta->($self, $v, $_)
         } $self->vals
-    } $self->vals)
-}
-
-sub d_e($self) {
-    return sum(map {
+    } $self->vals);
+    my $d_e = sum(map {
         my $v = $_;
         map {
             $self->_expected->{$v}{$_} * $self->delta->($self, $v, $_)
         } $self->vals
-    } $self->vals)
+    } $self->vals);
+    my $alpha = 1 - $d_o / $d_e;
+    return $alpha
 }
 
 sub vals($self) { @{ $self->_vals } }
@@ -294,14 +288,6 @@ frequencies).
 
 Returns a sorted list of all the possible values.
 
-=head2 d_o
-
-Returns the observed disagreement.
-
-=head2 d_e
-
-Returns the disagreement expected by chance.
-
 =head1 AUTHOR
 
 E. Choroba, C<< <choroba at cpan.org> >>

t/02-example.t

@@ -9,7 +9,7 @@ use Test2::Tools::Subtest qw{ subtest_buffered };
 plan 2;
 
 subtest_buffered wikipedia => sub {
-    plan 5;
+    plan 3;
     my @units_h = ({B=>2, C=>2}, {B=>1, C=>1}, {B=>3, C=>3}, {A=>3, B=>3, C=>4},
                    {A=>4, B=>4, C=>4}, {A=>1, B=>3}, {A=>2, C=>2}, {A=>1, C=>1},
                    {A=>1, C=>1}, {A=>3, C=>3}, {A=>3, C=>3}, {A=>3, C=>4});
@@ -19,8 +19,6 @@ subtest_buffered wikipedia => sub {
 
     is $sk1->alpha, float(0.691, precision => 3),
         'Hash units, default delta';
-    is $sk1->d_o, 6, 'd_o';
-    is $sk1->d_e, float(2 / 25 * (28 + 70 + 35 + 40 + 20 + 50)), 'd_e';
 
     my @units_a = ([undef, 2, 2],
                    [undef, 1, 1],