X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ian/git?p=appendix-a6.git;a=blobdiff_plain;f=compute-scottish-stv;h=43d3a7286f3158f8a09277aa6ca60042e9b96274;hp=e09f1ebcefb4430d7b8299afa0c27b8dcbd4d3e5;hb=49ea4a7c89f1a34aff1714a3dcbdc3a52f5990e6;hpb=4642960b13763e24dcb10ab40cd650e12e1f84fe

diff --git a/compute-scottish-stv b/compute-scottish-stv
index e09f1eb..43d3a72 100755
--- a/compute-scottish-stv
+++ b/compute-scottish-stv
@@ -31,6 +31,7 @@ our %cands;
 our $stage=0;
 our $quota;
 our %tie;
+our @elected;
 
 our $DIGS = 5;
 our $F = (new Math::BigRat 10)->bpow($DIGS);
@@ -57,6 +58,8 @@ $SIG{__DIE__} = sub {
     die $_[0];
 };
 
+sub total_history_cmp ();
+
 sub unkopt ($$) {
     my ($what,$opt) = @_;
     if ($opt =~ m/^[A-Z]/) {
@@ -66,6 +69,23 @@ sub unkopt ($$) {
     }
 }
 
+my $display_cmp = \&total_history_cmp;
+my $for_compare = 0;
+
+while (@ARGV && $ARGV[0] =~ m/^\-/) {
+    $_ = shift @ARGV;
+    if (m/^--$/) {
+	last;
+    } elsif (m/^--sort=alpha$/) {
+	$display_cmp = sub { $b->{Cand} cmp $a->{Cand} };
+    } elsif (m/^--for-compare$/) {
+	$for_compare = 1;
+	unshift @ARGV, '--sort=alpha';
+    } else {
+	die;
+    }
+}
+
 for (;;) {
     $_ = <>;
     if (m/^\| /) {
@@ -185,20 +205,28 @@ sub sv ($) {
 
 sub prf {
     my $fmt = shift;
-    printf "stage %d: ".$fmt, $stage, @_;
+    printf " ".$fmt, @_;
 }
 
 sub countballots () {
+    my @pr;
+
     foreach my $c (values %cands) {
 	next if $c->{NonCont};
 	$c->{Total} = 0/1;
 	$c->{Total} += $_->{Weight} foreach @{ $c->{Votes} };
 	print DEBUG "counted $c->{Cand} $c->{Total}\n";
 	$c->{History}[$stage-1] = $c->{Total};
+	push @pr, $c;
+    }
+
+    if ($for_compare) {
+	# for comparison with OpenSTV, which always prints
+	# the quota for every elected candidate
+	push @pr, { %$_, Total => $quota } foreach @elected;
     }
 
-    foreach my $c (reverse sort total_history_cmp
-		   grep { !$_->{NonCont} } values %cands) {
+    foreach my $c (reverse sort $display_cmp @pr) {
 	prf "candidate %-10s: %s votes\n", $c->{Cand}, sv $c->{Total};
     }
 }
@@ -206,8 +234,9 @@ sub countballots () {
 sub computequota () {
     my $totalvalid = 0/1;
     $totalvalid += $_->{Total} foreach values %cands;
-    $quota = floor($totalvalid / (1 + $seats));
-    prf "quota %s\n", sv $quota;
+    $quota = floor($totalvalid / (1 + $seats) + 1);
+    prf "total valid %s\n", sv $totalvalid;
+    prf "quota       %s\n", sv $quota;
 }
 
 sub total_history_cmp () {
@@ -288,22 +317,29 @@ sub elect_core ($) {
     my ($c) = @_;
     prf "*** ELECT %s \`%s' ***\n", $c->{Cand}, $c->{Desc};
     $c->{NonCont} = 'Elected';
+    push @elected, $c;
 }
 
 $stage = 0;
 
 for (;;) {
     $stage++;
+    printf "stage %3d:\n", $stage;
 
     sortballots @allvotes if $stage == 1;
 
-    my $seats_remain = $seats
-	- grep { ($_->{NonCont} // '') eq 'Elected' } values %cands;
+    my $seats_remain = $seats - @elected;
+
+    prf "seats remaining %d\n", $seats_remain;
+
+    last unless $seats_remain;
+
     if (continuing() <= $seats_remain) {
 	foreach my $c (continuing()) {
 	    prf "electing %s to fill remaining place(s)\n", $c->{Cand};
 	    elect_core $c;
 	}
+	countballots() if $for_compare;
 	last;
     }
 
@@ -328,6 +364,8 @@ for (;;) {
 	    next;
 	}
 
+	last if $seats_remain == 1; # don't bother doing more transfers
+
 	my $B = $c->{Total};
 	my %tspr;
 
@@ -348,7 +386,7 @@ for (;;) {
 		die unless $tspr{"@$previously"} == $xfervalue;
 	    } else {
 		$tspr{"@$previously"} = $xfervalue;
-		prf "transfer value of ballots %s: %s\n",
+		prf "transfer value of ballots %20s: %s\n",
 		    "@$previously", sv $xfervalue;
 	    }
 	}
@@ -375,4 +413,17 @@ for (;;) {
     die;
 }
 
-print "done.\n"; 
+print "Winners:\n"; 
+
+if ($for_compare) {
+    foreach my $c (sort { $a->{Cand} cmp $b->{Cand} } @elected) {
+	printf "  %s\n", $c->{Cand};
+    }
+} else {
+    foreach my $i (0..$#elected) {
+	my $c = $elected[$i];
+	printf " %3d. %-10s %s\n", $i+1, $c->{Cand}, $c->{Desc};
+    }
+}
+
+print "done.\n";