From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Mon, 1 Aug 2016 14:44:11 +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=24bf2bad96f040aacd4dd9ccdab7a300e812513b

stv: wip debug
---

diff --git a/stv b/stv
index 47984e8..bd95262 100755
--- a/stv
+++ b/stv
@@ -6,9 +6,10 @@
 use strict;
 use utf8;
 use autodie;
-#use bigrat;
+use bigrat;
+use Carp;
 use Data::Dumper;
-use List::Util qw(sum);
+use List::Util qw(sum0);
 use List::MoreUtils qw(nsort_by);
 
 # vote is
@@ -27,7 +28,7 @@ open DEBUG, ">.stv.log" or die $!;
 while (<>) {
     next if m/^\w+$/;
     m/^(\w+) ([A-Z]+)$/ or die "$_ ?";
-    my $prefs = $1;
+    my $prefs = $2;
     my $vote = {
         Voter => $1,
     	Weight => 1.0,
@@ -38,7 +39,8 @@ while (<>) {
 
 sub pr ($) {
     my ($f) = @_;
-    return sprintf "%10.6f=%-10s", $f, $f;
+    confess unless defined $f;
+    return sprintf "%10.6f = %-10s", $f, $f;
 }
 
 sub votelog ($$) {
@@ -83,7 +85,8 @@ sub equalpiles ($@) {
     my $eqtotal = $s->{Total};
     my $count = 0;
     while ($count < @sorted && $sorted[$count]{Total} == $eqtotal) {
-	printf "%7s %10s\n", $how, $sorted[$count]{Cand};
+	printf "%7s %10s %s\n", $how, $sorted[$count]{Cand},
+	    pr $sorted[$count]{Total};
 	$count++;
     }
     return @sorted[ 0 .. $count-1 ];
@@ -118,6 +121,8 @@ sub historically_prefer ($@) {
 for (;;) {
     $stage++;
 
+    printf "----- stage %d -----\n", $stage;
+
     print DEBUG "#################### $stage ####################\n",
 	Data::Dumper->Dump(
 [ \@stagerecord, \@elected, \@unsorted, \%sorted, \@surpluses, \%continuing ],
@@ -135,6 +140,7 @@ for (;;) {
     }
     $sorted{$_}{Cand} = $_ foreach keys %sorted;
     foreach my $firstpref (sort keys %sorted) {
+	$sorted{$firstpref}{Total} = 0; # recount
 	foreach my $vote (@{ $sorted{$firstpref}{Votes} }) {
 	    votelog $vote, "counted $vote->{Weight} for $firstpref";
 	    $sorted{$firstpref}{Total} += $vote->{Weight};
@@ -146,6 +152,8 @@ for (;;) {
     };
     $sort_update->();
 
+    print DEBUG "SORTED\n", Dumper(\@sorted);
+
     push @stagerecord, { map { ($_->{Cand}, $_->{Total}) } @sorted };
 
     my $totalvalid = 0;
@@ -159,7 +167,7 @@ for (;;) {
     $countvalid->(\@sorted,    '1stpref');
     $countvalid->(\@surpluses, 'surplus');
 
-    printf "%7s %10s %s\n", 'TOTAL', '', pr $totalvalid;
+    printf "%7s %10s %s\n", 'TOTAL', '-----', pr $totalvalid;
 
     unless ($totalvalid > 0) {
 	printf "No more votes!\n";
@@ -174,7 +182,7 @@ for (;;) {
     }
 
     my $quota = $totalvalid / ($placesremain + 1);
-    printf "%7s %10s %s\n", '', 'quota', pr $quota;
+    printf "%7s %10s %s\n", 'quota', '', pr $quota;
 
     my $need_to_transfer_surplus = 1;
 
@@ -183,15 +191,15 @@ for (;;) {
     # (ERS rules 5.4.9)
     for (;;) {
 	my $s = $sorted[0];
-	my $topvoters = $s->{Weight};
+	my $topvoters = $s->{Total};
 	my $surplus = $topvoters - $quota;
 	last unless $surplus > 0;
 
-	printf "%7s %10s\n", 'ELECTED', $s->{Cand};
+	printf "%7s %10s ***************\n", 'ELECTED', $s->{Cand};
 	push @elected, $s->{Cand};
 
 	my $derate = $topvoters / $surplus;
-	printf "%7s %10s\n", 'derate', $s->{Cand}, pr $derate;
+	printf "%7s %10s %s\n", 'derate', $s->{Cand}, pr $derate;
 
 	foreach my $vote (@{ $s->{Votes} }) {
 	    votelog $vote, "elected $s->{Cand}, derated $derate";
@@ -207,8 +215,8 @@ for (;;) {
 	# eliminating, and then reconsider with a lower quota
     }
 
-    my $deferredsurplus = sum map { $_->{Total} } @surpluses;
-    printf "%7s %10s %s\n", 'def.srp', 'total', pr $deferredsurplus;
+    my $deferredsurplus = sum0 map { $_->{Total} } @surpluses;
+    printf "%18s %s\n", 'deferred surplus', pr $deferredsurplus;
 
     # Look for people to eliminate
     # We eliminate before trying to transfer surpluses
@@ -216,13 +224,25 @@ for (;;) {
     for (;;) {
 	last unless @sorted;
 
-	my @elim = equalpiles 'elim?', reverse @sorted;
-	my $elimvote = sum map { $_->{Total} } @elim;
-	my $elimvotetotal = $elimvote * scalar @elim;
+	printf "%18s\n", 'elimination round';
 
-	if (@surpluses and $elimvotetotal > $deferredsurplus) {
-	    printf "no-elim, un-defer\n";
-	    last;
+	my @elim = equalpiles 'elim?', reverse @sorted;
+	my $elimvotetotal = sum0 map { $_->{Total} } @elim;
+
+	if (@surpluses) {
+	    if (@sorted == @elim) {
+		printf "%18s\n", 'no-elim, un-defer, (all-equal)';
+		last;
+	    }
+	    my $nextup = $sorted[ $#sorted - @elim ];
+	    printf "%7s %10s %s\n", 'nextup', $nextup->{Cand},
+		pr $nextup->{Total};
+	    my $aheadby = $nextup->{Total} - $elimvotetotal;
+	    unless ($deferredsurplus <= $aheadby) {
+		# rule 5.2.2 (b)
+		printf "%18s %s\n", 'no-elim, un-defer', pr $aheadby;
+		last;
+	    }
 	}
 
 	if ((scalar keys %continuing) - (scalar @elim) < $placesremain) {
@@ -233,7 +253,7 @@ for (;;) {
 
 	foreach my $s (@elim) {
 	    my $c = $s->{Cand};
-	    printf "%7s %10s\n", 'ELIM', $c;
+	    printf "%7s %10s %s\n", 'ELIM', $c, '----------';
 	    my $votes = $s->{Votes};
 	    votelog $_, "failed to stop $c elimination" foreach @$votes;
 	    delete $continuing{$c};
@@ -247,7 +267,7 @@ for (;;) {
     
     next unless $need_to_transfer_surplus;
 
-    @surpluses = nsort_by { $_->{Total} }, @surpluses;
+    @surpluses = nsort_by { $_->{Total} } @surpluses;
     my @surplusxfer = equalpiles 'xfer?', @surpluses;
     die unless @surplusxfer;