autodie

[appendix-a6.git] / parse

diff --git a/parse b/parse
index c9ebc344c98c4afa200f424d2ba208c3bc918830..16f09266a2471eff0551b4f25f31e5ba1a6951c8 100755 (executable)
--- a/parse
+++ b/parse
@@ -1,17 +1,20 @@
 #!/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;
 our @invotes;
 our $defcho;
+our $quorum = 0;
 
 sub addchoice {
     my $choname = shift @_;
@@ -34,6 +37,8 @@ while (<>) {
        }
     } elsif (m/^V:\s+(\S+)\s+(\S.*)/) {
        push @invotes, [ $1, $2 ];
+    } elsif (m/^quorum = ([0-9.]+)$/) {
+       $quorum = $1+0.0;
     } else {
        die "invalid input";
     }
@@ -46,7 +51,11 @@ if (!$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;
@@ -67,42 +76,123 @@ foreach my $iv (@invotes) {
            foreach my $ib ($ia+1..$#vs) {
                my $va = $vs[$ia];
                my $vb = $vs[$ib];
-               if ($va < $vb) { $vab[$ia][$ib]++; }
-               elsif ($vb < $va) { $vab[$ib][$ia]++; }
+               if ($va < $vb) { push @{ $vab[$ia][$ib] }, $voter }
+               elsif ($vb < $va) { push @{ $vab[$ib][$ia] }, $voter }
            }
        }
     };
     die "voter $voter $@" if $@;
 }
 
-foreach my $iy (-2..$#choices) {
-    foreach my $ix (-2..$#choices) {
+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] );
-           $$v += 0;
-           if ($$v) {
-               printf "%5d ", $$v or die $!;
+           $$v ||= [ ];
+           if (@$$v) {
+               printf "%5d ", (scalar @$$v);
            } else {
-               printf "%5s ", "" or die $!;
+               printf "%5s ", "";
            }
        }
     }
-    printf "\n" or die $!;
+    printf "\n";
+}
+
+sub drop ($$) {
+    my ($i,$why) = @_;
+    print "dropping $choices[$i]: $why\n";
+    $ch[$i]{Dropped} = $why;
+}
+
+print "# quorum A.6(2)\n";
+
+foreach my $i (0..$#choices) {
+    next if $ch[$i]{Dropped};
+    next if $i == $defi;
+    my $v = $vab[$i][$defi];
+    next if $v >= $quorum;
+    drop $i, "quorum ($v < $quorum)";
+}
+
+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]; # 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;