From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Mon, 1 Aug 2016 15:11:25 +0000 (+0100)
Subject: stv: wip debug
X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ian/git?p=appendix-a6.git;a=commitdiff_plain;h=79268be36a253e1396688eb9956e021bbfca53ef;hp=fa0279b26ffd9237060ac96f2a50e5e23daa246d

stv: wip debug
---

diff --git a/stv b/stv
index 7059906..a963609 100755
--- a/stv
+++ b/stv
@@ -118,6 +118,13 @@ sub historically_prefer ($@) {
     return $choices[0];
 }
 
+foreach my $c (keys %continuing) {
+    $sorted{$c} = {
+        Cand => $c,
+        Votes => [],
+    };
+}
+
 for (;;) {
     $stage++;
 
@@ -129,6 +136,13 @@ for (;;) {
 [qw( _@stagerecord _@elected _@unsorted _%sorted _@surpluses _%continuing )]
 	   );
 
+    my $placesremain = $places - @elected;
+
+    unless ($placesremain > 0) {
+	printf "Complete.\n";
+	last;
+    }
+
     while (my $vote = shift @unsorted) {
 	my ($firstpref) = grep { $continuing{$_} } @{ $vote->{Prefs} };
 	if (!defined $firstpref) {
@@ -138,7 +152,6 @@ for (;;) {
 	    push @{ $sorted{$firstpref}{Votes} }, $vote;
 	}
     }
-    $sorted{$_}{Cand} = $_ foreach keys %sorted;
     foreach my $firstpref (sort keys %sorted) {
 	foreach my $vote (@{ $sorted{$firstpref}{Votes} }) {
 	    votelog $vote, "counted $vote->{Weight} for $firstpref";
@@ -175,13 +188,6 @@ for (;;) {
 	last;
     }
 
-    my $placesremain = $places - @elected;
-
-    unless ($placesremain > 0) {
-	printf "Complete.\n";
-	last;
-    }
-
     my $quota = $totalvalid / ($placesremain + 1);
     printf "%7s %10s %s\n", 'quota', '', pr $quota;
 
@@ -224,31 +230,42 @@ for (;;) {
     # Look for people to eliminate
     # We eliminate before trying to transfer surpluses
     # ERS 5.2.5
+    my $elimvotebefore = 0;
     for (;;) {
 	last unless @sorted;
 
-	printf "%18s\n", 'elimination round';
+	if ($elimvotebefore) {
+	    printf "%18s %s\n", 'elimination, sofar', pr $elimvotebefore;
+	} elsif (@surpluses) {
+	    printf "%18s\n", 'elimination, maybe';
+	} else {
+	    printf "%18s\n", 'elimination, starts';
+	}
 
 	my @elim = equalpiles 'elim?', reverse @sorted;
-	my $elimvotetotal = sum0 map { $_->{Total} } @elim;
+	my $elimvotenow = sum0 map { $_->{Total} } @elim;
 
-	if (@surpluses) {
+	if (@surpluses || $elimvotebefore) {
+	    # rule 5.2.2
 	    if (@sorted == @elim) {
-		printf "%18s\n", 'no-elim, un-defer, (all-equal)';
+		printf "%18s\n", 'no-elim (all-equal)';
 		last;
 	    }
 	    my $nextup = $sorted[ $#sorted - @elim ];
 	    printf "%7s %10s %s\n", 'nextup', $nextup->{Cand},
 		pr $nextup->{Total};
-	    my $aheadby = $nextup->{Total} - $elimvotetotal;
+	    my $aheadby = $nextup->{Total} - ($elimvotenow + $elimvotebefore);
 	    unless ($deferredsurplus <= $aheadby) {
 		# rule 5.2.2 (b)
-		printf "%18s %s\n", 'no-elim, un-defer', pr $aheadby;
+		printf "%18s %s\n", 'no-elim (nextup)', pr $aheadby;
 		last;
 	    }
 	}
 
-	if ((scalar keys %continuing) - (scalar @elim) < $placesremain) {
+	my $elim_tie =
+	    @elim > 1 &&
+	    (scalar keys %continuing) - (scalar @elim) < $placesremain;
+	if ($elim_tie) {
 	    # eliminate only one then, and try again
 	    printf "elim-tie!\n";
 	    @elim = historically_prefer -1, @elim;
@@ -259,6 +276,7 @@ for (;;) {
 	    printf "%7s %10s %s\n", 'ELIM', $c, '----------';
 	    my $votes = $s->{Votes};
 	    votelog $_, "failed to stop $c elimination" foreach @$votes;
+	    $elimvotebefore += $s->{Total};
 	    delete $continuing{$c};
 	    delete $sorted{$c};
 	    push @unsorted, @$votes;
@@ -266,6 +284,7 @@ for (;;) {
 	
 	$things_update->();
 	$need_to_transfer_surplus = 0;
+	last if $elim_tie; # no more, then!
     }
     
     next unless $need_to_transfer_surplus;