X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ian/git?p=appendix-a6.git;a=blobdiff_plain;f=compute-scottish-stv;h=d92db96382bddeac989202ad6e937ca8f52f6ce6;hp=6fde10308b409753d9f877e1df709300d2558fa3;hb=5fc4bc0993f2f2dc97c43217b3c0bfc51cdf9415;hpb=a4f2fc687bb9e16c33a59619acafe2cc21833ee1

diff --git a/compute-scottish-stv b/compute-scottish-stv
index 6fde103..d92db96 100755
--- a/compute-scottish-stv
+++ b/compute-scottish-stv
@@ -35,15 +35,25 @@ our %tie;
 open DEBUG, ">.compute.log" or die $!;
 DEBUG->autoflush(1);
 
-$SIG{__WARN__} = sub {
+sub debug_dump () {
     print DEBUG Dumper(\%tie,
 		       \@non_transferable,
 		       \%cands,
 		       \@allvotes,
 		       $stage, $quota);
+}
+
+$SIG{__WARN__} = sub {
+    $SIG{__DIE__} = undef;
+    debug_dump;
     confess $_[0];
 };
 
+$SIG{__DIE__} = sub {
+    debug_dump;
+    die $_[0];
+};
+
 sub unkopt ($$) {
     my ($what,$opt) = @_;
     if ($opt =~ m/^[A-Z]/) {
@@ -98,6 +108,7 @@ for (;;) {
 $cands{$_}{Cand} = $_ foreach keys %cands;
 $_->{Weight} //= 1/1 foreach @allvotes;
 $_->{TransferredSurplus} //= [ ] foreach @allvotes;
+$_->{OrigPrefs} //= [ @{ $_->{Prefs} } ] foreach @allvotes;
 
 sub votelog ($$) {
     my ($vote,$m) = @_;
@@ -111,6 +122,7 @@ sub sortballots (@) {
     # Strips that first preference from the ballot.
     # If the first preference has been eliminated, strips it
     # and looks for further preferences.
+    print DEBUG "sortballots ".(scalar @_)."...\n";
     foreach my $v (@_) {
 	my $firstprefs = shift @{ $v->{Prefs} };
 	my $w = $v->{Weight};
@@ -150,18 +162,22 @@ sub prf {
 }
 
 sub countballots () {
-    foreach my $cand (sort keys %cands) {
-	my $c = $cands{$cand};
+    foreach my $c (values %cands) {
 	next if $c->{NonCont};
-	$c->{Total} = 0;
+	$c->{Total} = 0/1;
 	$c->{Total} += $_->{Weight} foreach @{ $c->{Votes} };
-	prf "candidate %-10s: %10s votes\n", $cand, $c->{Total};
+	print DEBUG "counted $c->{Cand} $c->{Total}\n";
 	$c->{History}[$stage-1] = $c->{Total};
     }
+
+    foreach my $c (reverse sort total_history_cmp
+		   grep { !$_->{NonCont} } values %cands) {
+	prf "candidate %-10s: %10s votes\n", $c->{Cand}, $c->{Total};
+    }
 }
 
 sub computequota () {
-    my $totalvalid = 0;
+    my $totalvalid = 0/1;
     $totalvalid += $_->{Total} foreach values %cands;
     $quota = ($totalvalid / (1 + $seats)) -> bfloor();
     prf "quota %10s\n", $quota;
@@ -170,13 +186,15 @@ sub computequota () {
 sub total_history_cmp () {
     my $ha = $a->{History};
     my $hb = $b->{History};
+    my $m = "stage $stage history cmp $a->{Cand} $b->{Cand}";
+    print DEBUG  "$m...\n";
     foreach my $s (reverse 0 .. $stage-1) {
 	my $d = $ha->[$s] <=> $hb->[$s];
 	next unless $d;
-	print DEBUG "history cmp $a->{Cand} $b->{Cand}".
-	    " => $d (#$s $ha->[$s] $hb->[$s])\n";
+	print DEBUG "$m => $d (#$s $ha->[$s] $hb->[$s])\n";
 	return $d;
     }
+    print DEBUG "$m => 0\n";
     return 0;
 }
 
@@ -205,13 +223,14 @@ sub select_best_worst ($$$$) {
 
     for (;;) {
 	my $nextc = $maybe[$nequal];
+	last unless $nextc;
 
 	# Only interested in those who compare equal according to the
 	# history (SLGEO 49(2)); NB our history includes the current
 	# round.
 	
 	last if $signum*($a = $maybe[0], $b = $nextc, total_history_cmp) > 0;
-	$nextc++;
+	$nequal++;
     }
 
     if ($nequal > 1 && !$wanttiebreak->($maybe[0]{Total})) {
@@ -244,15 +263,13 @@ sub elect_core ($) {
     $c->{NonCont} = 'Elected';
 }
 
-$stage = 1;
-
-sortballots @allvotes;
-countballots();
-computequota();
+$stage = 0;
 
 for (;;) {
     $stage++;
 
+    sortballots @allvotes if $stage == 1;
+
     my $seats_remain = $seats
 	- grep { ($_->{NonCont} // '') eq 'Elected' } values %cands;
     if (continuing() <= $seats_remain) {
@@ -265,6 +282,8 @@ for (;;) {
 
     countballots();
 
+    computequota if $stage == 1;
+
     my $c = select_best_worst
 	sub { $_->{Total} >= $quota },
 	sub { $_ > $quota },
@@ -277,7 +296,7 @@ for (;;) {
 	# SLGEO 48
 	my $surplus = $c->{Total} - $quota;
 
-	if ($surplus <= 0) {
+	if ($surplus <= 0/1) {
 	    prf "no surplus\n";
 	    next;
 	}
@@ -306,8 +325,9 @@ for (;;) {
 		prf "transfer value of ballots %s: %10s\n",
 		    "@$previously", $xfervalue;
 	    }
-	    sortballots $v;
 	}
+	sortballots @{ $c->{Votes} };
+
 	$c->{Votes} = { }; # will crash if we access it again
 	next;
     }
@@ -319,8 +339,10 @@ for (;;) {
 	-1, 'eliminating';
 
     if ($c) {
-	prf "=== eliminating %s (%s) ===\n", $c->{Cand}, $c->{Desc};
+	prf "=== eliminating %s \`%s' ===\n", $c->{Cand}, $c->{Desc};
 	$c->{NonCont} = 'Eliminated';
+
+	sortballots @{ $c->{Votes} };
 	next;
     }