#!/usr/bin/perl -w
+#
+# parses some input about ballots and computes the result according
+# to Debian Constitution A.6.
+#
+# usage: .../compute [<input files>...]
+# (uses stdin if none supplied)
+#
+# input files can be in any order and should contain lines like:
+#
+# <votername> :: <PREF>, (<PREF>=<PREF>), <PREF>, ....
+# V: <tallyprefs> <votername>
+# <ABBREV> = <description...>
+# <ABBREV> = <description...> [<rat>:<io>]
+# <ABBREV> = <description...> [default]
+# nodefault
+# quorum = <quorum>
+#
+# where
+#
+# <votername> is any non-whitespace characters
+#
+# <ABBREV> and <PREF> are abbreviations for choices on the ballot.
+# They must be ASCII alphanumeric. Numeric preferences are
+# not recommended as they are confusing (particularly when
+# tally sheets are in use).
+#
+# It is best to avoid FD, SQ and NOTA except for the default
+# option; if no default option is specified, it will default
+# to one of these unless a "nodefault" line is found.
+#
+# In the "::" form, the commas are optional. Either ( ) or = may
+# be used to indicate a set of equal preferences.
+#
+# <tallyprefs> is a tally sheet preference order: that is,
+# a single uppercase base36 digit for each ballot choice,
+# (in the order they were specified by "=" lines), giving
+# the voter's preference rank for that option. The numbers
+# need not be distinct or contiguous. "-" may be used for
+# unranked preferences.
+#
+# <rat>:<io> is the majority ratio for the option
+#
+# <quorum> is the quorum
+#
+# and also allowed are
+#
+# #-comments } all
+# blank lines } ignored
+# lines starting with whitespace }
+
use strict;
use utf8;
use autodie;
-use Data::Printer;
use Graph::Directed;
+use Graph::Writer::GraphViz;
binmode STDIN, 'encoding(UTF-8)';
binmode STDOUT, 'encoding(UTF-8)';
our $defcho;
our $quorum = 0;
+our $gfile;
+
+while (@ARGV && $ARGV[0] =~ /^-/) {
+ local $_ = shift @ARGV;
+ if (m/^--?$/) {
+ last;
+ } elsif (s/^-g//) {
+ $gfile = $_;
+ } else {
+ die "bad usage\n";
+ }
+}
+
sub addchoice {
my $choname = shift @_;
- my $cho = $choices{$choname} = { @_, Index => (scalar @choices) };
+ my $cho = $choices{$choname} = {
+ @_, Index => (scalar @choices)
+ };
push @choices, $choname;
return $cho;
}
next if m/^\s*\#/;
next unless m/\S/;
next if m/^\s/;
- if (m/^([A-Z]+)\s*\=\s*(\S.*)$/) {
+ if (m/^([A-Z0-9]+)\s*\=\s*(\S.*)$/) {
my ($choname, $desc) = ($1,$2);
my $cho = addchoice($choname, Desc => $desc);
if ($desc =~ m/\[(\d+):(\d+)\]/) {
push @invotes_cc, [ $1, "$'" ];
} elsif (m/^quorum = ([0-9.]+)$/) {
$quorum = $1+0.0;
+ } elsif (m/^nodefault$/) {
+ $defcho = { Index => -1 }
} else {
die "invalid input";
}
}
-$defcho ||= $choices{FD};
-if (!$defcho) {
- $defcho = addchoice('FD', Desc => "Further Discussion");
-}
-my $defi = $defcho->{Index};
-die "FD has smaj?!" if $defcho->{Smaj};
-
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)
-print "\nPreference matrix\n";
+print "\nParsing \`simple' style ballots\n# devotee-tally-begin\n"
+ if @invotes_cc;
+# actually, we pre-parse them into @invotes_v
+# since we want to show them as a tally sheet anyway
foreach my $iv (@invotes_cc) {
$_ = uc $iv->[1];
foreach my $chn (m/\b\w+\b/g) {
- $choices{$chn} or addchoice($chn, Desc => "($chn from voter ballot)");
+ next if $choices{$chn};
+ addchoice($chn, Desc => "($chn from voter ballot)");
}
}
foreach (split /\s+/) {
foreach (split /=/) {
my $cho = $choices{$_};
- $cho or die "unknown option $_ ($voter)";
+ $cho or die "unknown choice $_ ($voter)";
my $ix = $cho->{Index};
$ranks[$ix] = $rank;
}
push @invotes_v, [ $vstr, $voter ];
}
+print "# devotee-tally-end\n"
+ if @invotes_cc;
+
+print "\nDetermining default option\n";
+
+if ($defcho && $defcho->{Index} > -1) {
+ print "default option was specified: $choices[$defcho->{Index}]\n";
+} elsif ($defcho) {
+ print "no default option\n";
+} else {
+ foreach my $try (qw(FD SQ NOTA)) {
+ $defcho = $choices{$try};
+ last if $defcho;
+ }
+ if ($defcho) {
+ print "guessed default option: $choices[$defcho->{Index}]\n";
+ } else {
+ print "could not guess default option, assuming there is none\n";
+ }
+}
+
+my $defi = $defcho->{Index};
+die "FD has smaj?!" if $defcho->{Smaj};
+
+print "\nParsing devotee tally sheet ballots\n"
+ if @invotes_v > @invotes_cc;
+
foreach my $iv (@invotes_v) {
my ($votestr,$voter) = @$iv;
eval {
die "voter $voter $@" if $@;
}
+print "\nPreference matrix\n";
+
our @ch = map { $choices{$_} } @choices;
# Print the counts V(A,B)
$ch[$i]{Dropped} = $why;
}
-print "\nQuorum A.6(2) (quorum is $quorum)\n";
+if (defined $defi) {
+ print "\nQuorum A.6(2) (quorum is $quorum)\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)";
-}
+ 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 "\nMajority 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])";
+ print "\nMajority 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:$vda <= $majr->[1]:$majr->[0])";
+ }
}
print "\nDefeats A.6(4)\n";
return 0;
}
+our $showg = $defeats->deep_copy();
+
our $schwartz;
for (;;) {
my $tdefeats = $defeats->transitive_closure();
+ # this makes the debugging output prettier
+ foreach my $ch (@choices) {
+ $tdefeats->delete_edge($ch,$ch);
+ }
print "closure graph: $tdefeats\n";
print "\nSchwartz set A.6(6)\n";
printf " %-5s %s\n", $_, $choices{$_}{Desc}
foreach ($schwartz->vertices());
+if (defined $gfile) {
+ foreach my $cho (values %choices) {
+ my $chn = $choices[$cho->{Index}];
+ my $label = "\\N\n$cho->{Desc}";
+ if ($cho->{Dropped}) {
+ $label .= "\nDropped: $cho->{Dropped}";
+ }
+ $showg->set_vertex_attribute($chn, 'label', $label);
+ }
+
+ my $gwriter = new Graph::Writer::GraphViz -format => 'ps';
+ $gwriter->write_graph($showg, $gfile);
+}
+
print ".\n";
#p %choices;
~ian / appendix-a6.git / blobdiff