autodie

[appendix-a6.git] / parse

diff --git a/parse b/parse
index 8828deec85ee3542e80421a56ce13d2a3a034a6e..16f09266a2471eff0551b4f25f31e5ba1a6951c8 100755 (executable)
--- a/parse
+++ b/parse
@@ -1,12 +1,14 @@
 #!/usr/bin/perl -w
 use strict;
 use utf8;
+use autodie;
 
 use Data::Printer;
+use Graph::Directed;
 
-binmode STDIN, 'encoding(UTF-8)' or die;
-binmode STDOUT, 'encoding(UTF-8)' or die;
-binmode STDERR, 'encoding(UTF-8)' or die;
+binmode STDIN, 'encoding(UTF-8)';
+binmode STDOUT, 'encoding(UTF-8)';
+binmode STDERR, 'encoding(UTF-8)';
 
 our @choices;
 our %choices;
@@ -49,7 +51,11 @@ if (!$defcho) {
 my $defi = $defcho->{Index};
 die "FD has smaj?!" if $defcho->{Smaj};
 
-our @vab; # $vab[$ia][$ib] = V(A,B)
+our @vab;
+# $vab[$ia][$ib] = V(A,B)
+# Actually, it's a list of voters who prefer A to B (A.6(3)(1))
+
+# Go through the voters and construct V(A,B)
 
 foreach my $iv (@invotes) {
     my ($votestr,$voter) = @$iv;
@@ -80,33 +86,34 @@ foreach my $iv (@invotes) {
 
 our @ch = map { $choices{$_} } @choices;
 
+# Print the counts V(A,B)
 foreach my $iy (-2..$#ch) {
     foreach my $ix (-2..$#ch) {
        if ($iy==-1) {
            if ($ix==-1) {
-               printf "+" or die;
+               printf "+";
            } else {
-               printf "------" or die;
+               printf "------";
            }
        } elsif ($ix==-1) {
-           printf "|" or die;
+           printf "|";
        } elsif ($ix==-2 && $iy==-2) {
-           printf "V(Y,X)" or die;
+           printf "V(Y,X)";
        } elsif ($iy==-2) {
-           printf "%5s ", $choices[$ix] or die $!;
+           printf "%5s ", $choices[$ix];
        } elsif ($ix==-2) {
-           printf "%5s ", $choices[$iy] or die $!;
+           printf "%5s ", $choices[$iy];
        } else {
            my $v = \( $vab[$iy][$ix] );
            $$v ||= [ ];
            if (@$$v) {
-               printf "%5d ", (scalar @$$v) or die $!;
+               printf "%5d ", (scalar @$$v);
            } else {
-               printf "%5s ", "" or die $!;
+               printf "%5s ", "";
            }
        }
     }
-    printf "\n" or die $!;
+    printf "\n";
 }
 
 sub drop ($$) {
@@ -115,7 +122,7 @@ sub drop ($$) {
     $ch[$i]{Dropped} = $why;
 }
 
-print "# quorum\n" or die;
+print "# quorum A.6(2)\n";
 
 foreach my $i (0..$#choices) {
     next if $ch[$i]{Dropped};
@@ -125,19 +132,67 @@ foreach my $i (0..$#choices) {
     drop $i, "quorum ($v < $quorum)";
 }
 
-print "# maj. ratio\n" or die;
+print "# maj. ratio A.6(3)\n";
 
 foreach my $i (0..$#choices) {
     next if $ch[$i]{Dropped};
     next if $i == $defi;
     my $majr = $ch[$i]{Smaj};
-    $majr ||= [1,1];
+    $majr ||= [1,1]; # A.6(3)(3)
     my $vad = scalar @{ $vab[$i][$defi] };
     my $vda = scalar @{ $vab[$defi][$i] };
     next if $vad * $majr->[1] > $vda * $majr->[0];
     drop $i, "majority ratio ($vad * $majr->[1] <= $vda * $majr->[0])";
 }
 
+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];
+       next unless $vab > $vba;
+       print "defeat: $choices[$ia] beats $choices[$ib] ($vab > $vba)\n";
+       $defeats->add_vertex($ia,$ib);
+    }
+}
+
+print "# transitive closure A.6(5)\n";
+
+my $tdefeats = $defeats->transitive_closure();
+
+print "# schwartz set A.6(6)\n";
+
+my $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);
+       print "not in Schwartz set: $choices[$ia] because $choices[$ib]\n";
+       $schwartz->delete_vertex($ia);
+       last;
+    }
+}
+
+print "# dropping weakest defeats A.6(7)\n";
+
+my @weakest = ();
+
+foreach my $edge (@{ $schwartz->edges() }) {
+    if (!@weakest) {
+       # no weakest edges yet
+    } elsif (weaker($edge, $weakest[0])) {
+       # this edge is weaker than previous weakest, start new set
+       @weakest = ();
+    } elsif (weaker($weakest[0], $edge)) {
+       # weakest edge is weaker than this one, ignore this one
+       next;
+    } else {
+       # weakest edge is exactly as weak as this one, add this one
+    }
+    push @weakest, $edge;
+}
 
-#p %choices;
+b#p %choices;
 #p @vab;