X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ian/git?p=appendix-a6.git;a=blobdiff_plain;f=parse;h=a1ce9c587747aa906135ea656f98b04ccb3257fe;hp=c04d33b0083cea24f5495e5b35d9e2318083fe1e;hb=0651d6b71fb087495c174faac376b5c9c60c0bfc;hpb=0627d3e30d981724e0f97939b551d59a8e167d79

diff --git a/parse b/parse
index c04d33b..a1ce9c5 100755
--- a/parse
+++ b/parse
@@ -57,6 +57,8 @@ our @vab;
 
 # Go through the voters and construct V(A,B)
 
+print "\nDefeats matrix\n";
+
 foreach my $iv (@invotes) {
     my ($votestr,$voter) = @$iv;
     eval {
@@ -122,7 +124,7 @@ sub drop ($$) {
     $ch[$i]{Dropped} = $why;
 }
 
-print "# quorum A.6(2)\n";
+print "\nQuorum A.6(2) (quorum is $quorum)\n";
 
 foreach my $i (0..$#choices) {
     next if $ch[$i]{Dropped};
@@ -132,7 +134,7 @@ foreach my $i (0..$#choices) {
     drop $i, "quorum ($v < $quorum)";
 }
 
-print "# maj. ratio A.6(3)\n";
+print "\nMajority ratio A.6(3)\n";
 
 foreach my $i (0..$#choices) {
     next if $ch[$i]{Dropped};
@@ -147,24 +149,34 @@ foreach my $i (0..$#choices) {
 
 my $defeats = Graph::Directed->new; # A.6(4)
 
-foreach my $ia (0..$#ch) {
-    foreach my $ib (0..$#ch) {
-	my $vab = $vab[$ia][$ib];
-	my $vba = $vab[$ib][$ia];
+sub chremain () {
+    return grep { !$ch[$_]{Dropped} } (0..$#ch);
+}
+
+foreach my $ia (chremain()) {
+    $defeats->add_vertex($choices[$ia]);
+    foreach my $ib (chremain()) {
+	my $vab = scalar @{ $vab[$ia][$ib] };
+	my $vba = scalar @{ $vab[$ib][$ia] };
 	next unless $vab > $vba;
 	print "defeat: $choices[$ia] beats $choices[$ib] ($vab > $vba)\n";
-	$defeats->add_vertex($ia,$ib);
+	$defeats->add_vertex($choices[$ia],$choices[$ib]);
     }
 }
 
+sub chvab ($$) {
+    my ($ca,$cb) = @_;
+    return $vab[ $choices{$ca}{Index} ][ $choices{$cb}{Index} ];
+}
+
 sub weaker ($$) {
     # A.6(7)(1)
     my ($def1,$def2) = @_;
-    my ($ia,$ix) = @$def1;
-    my ($ib,$iy) = @$def1;
-    return 1 if $vab[$ia][$ix] < $vab[$ib][$iy];
-    return 1 if $vab[$ia][$ix] == $vab[$ib][$iy]
-	&& $vab[$ix][$ia] > $vab[$iy][$ib];
+    my ($ca,$cx) = @$def1;
+    my ($cb,$cy) = @$def1;
+    return 1 if chvab($ca, $cx) < chvab($cb, $cy);
+    return 1 if chvab($ca, $cx) == chvab($cb, $cy)
+	&& chvab($cx, $ca) > chvab($cy, $cb);
     return 0;
 }
 
@@ -173,29 +185,33 @@ our $schwartz;
 for (;;) {
     # loop from A6(5)
 
-    print "# transitive closure A.6(5)\n";
+    print "defeats graph: $defeats\n";
+
+    print "\nTransitive closure A.6(5)\n";
 
     my $tdefeats = $defeats->transitive_closure();
 
-    print "# schwartz set A.6(6)\n";
+    print "closure graph: $tdefeats\n";
+
+    print "\nSchwartz set A.6(6)\n";
     
     $schwartz = $defeats->copy();
 
-    foreach my $ia (0..$#ch) {
-	foreach my $ib (0..$#ch) {
-	    next if $tdefeats->has_edge($ia,$b);
-	    next if !$tdefeats->has_edge($b,$ia);
+    foreach my $ia (chremain()) {
+	foreach my $ib (chremain()) {
+	    next if $tdefeats->has_edge($choices[$ia],$choices[$ib]);
+	    next if !$tdefeats->has_edge($choices[$ib],$choices[$ia]);
 	    print "not in Schwartz set: $choices[$ia] because $choices[$ib]\n";
 	    $schwartz->delete_vertex($ia);
 	    last;
 	}
     }
 
-    print "# dropping weakest defeats A.6(7)\n";
+    print "\nDropping weakest defeats A.6(7)\n";
 
     our @weakest = ();
 
-    foreach my $edge (@{ $schwartz->edges() }) {
+    foreach my $edge ($schwartz->edges()) {
 	if (!@weakest) {
 	    # no weakest edges yet
 	} elsif (weaker($edge, $weakest[0])) {
@@ -213,21 +229,28 @@ for (;;) {
     last unless @weakest;
     
     printf "weakest defeats %d > %d", 
-	(scalar @{ $vab[$_->[0]][$_->[1]]) },
-	(scalar @{ $vab[$_->[1]][$_->[0]]) };
+	(scalar @{ $vab[$_->[0]][$_->[1]] }),
+	(scalar @{ $vab[$_->[1]][$_->[0]] });
     foreach my $weakest (@weakest) {
 	my ($ia,$ib) = @$weakest;
 	print "weakest defeat $choices[$ia] > $choices[$ib]\n";
-	$defeats->delete_edge($ia,$ib);
+	$defeats->delete_edge($choices[$ia],$choices[$ib]);
     }
 
-    print "# defeats within the Schwartz set, round again\n";
+    print "defeats within the Schwartz set, round again\n";
 }
 
-print "# no defeats within the Schwartz set\n";
-print "FINAL SCHWARTZ SET:\n";
+print "no defeats within the Schwartz set\n";
+print "final schwartz set:\n\n";
+
+if ($schwartz->vertices() == 1) {
+    print "WINNER IS:\n";
+} else {
+    print "WINNER IS ONE OF (CASTING VOTE DECIDES):\n";
+}
 
-print $choices[$_] foreach (@{ $schwartz->nodes() });
+printf "    %-5s %s\n", $_, $choices{$_}{Desc}
+    foreach ($schwartz->vertices());
 
 print ".\n";