stv: fix ties

[appendix-a6.git] / stv

diff --git a/stv b/stv
index fbd7b41050b18f535931223c8b7e0d8534c9f095..dae5563dd79bfd6a46474a7c3e08a61d0b385d51 100755 (executable)
--- a/stv
+++ b/stv
@@ -84,7 +84,7 @@ sub equalpiles ($@) {
     return () unless @sorted;
     my $s = $sorted[0];
     my $eqtotal = $s->{Total};
-    my $count = 0;
+    my $count = 0/1;
     while ($count < @sorted && $sorted[$count]{Total} == $eqtotal) {
        printf "%7s %10s %s\n", $how, $sorted[$count]{Cand},
            pr $sorted[$count]{Total};
@@ -140,7 +140,7 @@ for (;;) {
     my $placesremain = $places - @elected;
 
     unless ($placesremain > 0) {
-       printf "Complete.\n";
+       printf "Complete: @elected\n";
        last;
     }
 
@@ -155,7 +155,7 @@ for (;;) {
     }
     foreach my $firstpref (sort keys %sorted) {
        foreach my $vote (@{ $sorted{$firstpref}{Votes} }) {
-           votelog $vote, "counted $vote->{Weight} for $firstpref";
+           votelog $vote, "counted for $firstpref ".pr $vote->{Weight};
        }
     }
     my @sorted;
@@ -171,7 +171,7 @@ for (;;) {
 
     push @stagerecord, { map { ($_->{Cand}, $_->{Total}) } @sorted };
 
-    my $totalvalid = 0;
+    my $totalvalid = 0/1;
     my $countvalid = sub {
        my ($l, $what) = @_;
        foreach my $s (@$l) {
@@ -194,6 +194,8 @@ for (;;) {
 
     my $need_to_transfer_surplus = 1;
 
+    my @newsurpluses;
+
     # Look for people to elect.
     # We elect as many as we can, rather than recomputing the (lower) quota
     # (ERS rules 5.4.9)
@@ -201,21 +203,57 @@ for (;;) {
        my $s = $sorted[0];
        my $topvoters = $s->{Total};
        my $surplus = $topvoters - $quota;
-       last unless $surplus > 0;
+       last unless $surplus >= 0;
+
+       my @elect = equalpiles 'elect?', @sorted;
+
+       if (@elect > $placesremain) {
+           # oh my god
+           @elect = historically_prefer +1, @elect;
+           printf "%7s %10s\n", 'tie!', $elect[0]{Cand};
+       }
 
-       printf "%7s %10s ***************\n", 'ELECTED', $s->{Cand};
-       push @elected, $s->{Cand};
+       foreach $s (@elect) {
+           printf "%7s %10s ***************\n", 'ELECTED', $s->{Cand};
+           push @elected, $s->{Cand};
 
-       my $derate = $topvoters / $surplus;
-       printf "%7s %10s %s\n", 'derate', $s->{Cand}, pr $derate;
+           foreach my $vote (@{ $s->{Votes} }) {
+               votelog $vote, "elected $s->{Cand}";
+           }
 
-       foreach my $vote (@{ $s->{Votes} }) {
-           votelog $vote, "elected $s->{Cand}, derated $derate";
-           $vote->{Weight} /= $derate;
+           $s->{Surplus} = $surplus;
+           push @newsurpluses, $s;
+           delete $sorted{ $s->{Cand} };
+           delete $continuing{ $s->{Cand} };
+       }
+
+       $things_update->();
+    }
+
+    foreach my $s (@newsurpluses) {
+       # calculate the transfer value of each surplus
+       # we do this simultaneously, but based on the number of
+       # continuing candidates (excluding all the ones elected already)
+       # ERS rule 5.3.3
+
+       my $votes = $s->{Votes};
+       my $surplus = $s->{Surplus};
+       my $transferrable =
+           sum0
+           map { $_->{Weight} }
+           grep { !!voteliveprefs $_ }
+           @$votes;
+
+       printf "%7s %10s %s\n", 'xfrable', $s->{Cand}, pr $transferrable;
+       if ($transferrable > $surplus) {
+           my $derate = $transferrable / $surplus;
+           printf "%7s %10s %s\n", 'derate', $s->{Cand}, pr $derate;
+           foreach my $vote (@{ $s->{Votes} }) {
+               votelog $vote, "part of surplus, derated ". pr $derate;
+               $vote->{Weight} /= $derate;
+           }
        }
        push @surpluses, $s;
-       delete $sorted{ $s->{Cand} };
-       delete $continuing{ $s->{Cand} };
 
        $things_update->();
        printf "%7s %10s %s\n", 'surplus', $s->{Cand}, pr $s->{Total};
@@ -231,7 +269,7 @@ for (;;) {
     # Look for people to eliminate
     # We eliminate before trying to transfer surpluses
     # ERS 5.2.5
-    my $elimvotebefore = 0;
+    my $elimvotebefore = 0/1;
     for (;;) {
        last unless @sorted;