my $widists= Graph::Undirected->new();
my $wiarchs= Graph::Undirected->new();
+my $wispr;
+my $dbspr;
my @wiarchlabels;
my %wiisland2node;
my %winode2island;
my %winode2lines;
my %wiccix2arch;
+my $wialldists;
my $dbdists= Graph::Undirected->new();
my %dbisland2arch;
-my %msgcount;
-sub perr ($$) { print STDERR "$_[0]: $_[1]\n"; $msgcount{$_[0]}++; }
-sub warning ($) { perr("warning",$_[0]); }
-sub error ($) { perr("error", $_[0]); }
-sub change ($) { perr("change", $_[0]); }
+my %msgs;
+sub pmsg ($$) { push @{ $msgs{$_[0]} }, "$_[0]: $_[1]\n"; }
+sub warning ($) { pmsg("warning",$_[0]); }
+sub error ($) { pmsg("error", $_[0]); }
+sub change ($) { pmsg("change", $_[0]); }
+sub print_messages () {
+ foreach my $k (qw(change warning error)) {
+ my $m= $msgs{$k};
+ next unless $m;
+ print sort @$m or die $!;
+ }
+}
+sub progress ($) { print "($_[0])\n"; }
if (@ARGV && $ARGV[0] eq '--debug') {
shift @ARGV;
return $n;
}
-sub parse_yppedia_map () {
+sub yppedia_chart_parse () {
# We don't even bother with tag soup; instead we do line-oriented parsing.
while (<>) {
$winode2island{$n}= $island;
$widists->add_vertex($n);
$wiarchs->add_vertex($n);
-#print "\$g->add_vertex('$n');\n";
printf DEBUG "%2d,%-2d island %s\n", $x,$y,$island;
} elsif (($solid,$x,$y,$dirn) =
m/^\{\{ chart\ league((?:\ solid)?) \|(\d+)\|(\d+)\|
elsif ($dirn eq '/') { $x++; $by++; }
else { die; }
- $widists->add_weighted_edge($nn->(), nn_xy($bx,$by), 1);
- $wiarchs->add_edge($nn->(), nn_xy($bx,$by)) if $solid;
- $wiarchs->add_edge($nn->(), nn_xy($bx,$by)) if $solid;
-#print "\$g->add_edge('".$nn->()."','".nn_xy($bx,$by)."');\n" if $solid;
+ my $nb= nn_xy($bx,$by);
+ $widists->add_weighted_edge($nn->(), $nb, 1);
+ $wiarchs->add_edge($nn->(), $nb) if $solid;
+ $wiarchs->add_edge($nn->(), $nb) if $solid;
- printf DEBUG "%2d,%-2d league %-6s %s\n", $x,$y,
- $solid?'solid':'dotted', $dirn;
+ printf DEBUG "%2d,%-2d league %-6s %s %s\n", $x,$y,
+ $solid?'solid':'dotted', $dirn, $nb;
} elsif (
m/^\{\{ chart\ head \}\}$/xi
) {
}
}
-sub parse_database_map () {
+sub database_fetch_ocean () {
my ($row,$sth);
$sth= $dbh->prepare('SELECT islandname, archipelago FROM islands');
$sth->execute();
}
}
-sub process_yppedia_graphs () {
+sub database_graph_spr () {
+ $dbspr= shortest_path_reduction('db',$dbdists);
+}
- # Prune the LP database by eliminating boring intermediate vertices
+sub yppedia_graphs_add_shortcuts () {
+ # We add edges between LPs we know about, as you can chart
+ # between them. Yppedia often lacks these edges.
#
+ foreach my $p ($widists->vertices) {
+ my ($ax,$ay) = $p =~ m/^(\d+)\,(\d+)$/ or die;
+ my $add_shortcut= sub {
+ my $q= sprintf "%d,%d", $ax+$_[0], $ay+$_[1];
+ return unless $widists->has_vertex($q);
+ return if $widists->has_edge($p,$q);
+ printf DEBUG "%-5s league-shortcut %-5s\n", $p, $q;
+ $widists->add_weighted_edge($p,$q,1);
+ };
+ $add_shortcut->( 2,0);
+ $add_shortcut->(+1,1);
+ $add_shortcut->(-1,1);
+ }
+}
+
+sub yppedia_graphs_prune_boring () {
+ # Prune the LP database by eliminating boring intermediate vertices
foreach my $delete ($widists->vertices()) {
next if exists $winode2island{$delete};
my @neigh= $widists->neighbours($delete);
next unless @neigh==2;
-# my @aneigh= $wiarchs->has_vertex($delete)
-# ? $wiarchs->neighbours($delete) : ();
-# next unless @aneigh==0 || @aneigh==2;
my $weight= 0;
map { $weight += $widists->get_edge_weight($delete, $_) } @neigh;
$widists->add_weighted_edge(@neigh, $weight);
$widists->delete_vertex($delete);
printf DEBUG "%-5s elide %5s %-5s %2d\n", $delete, @neigh, $weight;
}
+}
+sub yppedia_graphs_check () {
# Check that it's connected.
- #
foreach my $cc ($widists->connected_components()) {
next if 2*@$cc > $widists->vertices();
my $m= "disconnected league point(s):";
}
warning($m);
}
+}
+sub yppedia_archs_sourceinfo () {
# Assign archipelagoes according to the source-info file
- #
foreach my $arch (sort keys %{ $oceans{$ocean} }) {
foreach my $islename (sort keys %{ $oceans{$ocean}{$arch} }) {
my $islenode= $wiisland2node{$islename};
$wiccix2arch{$ccix}= $arch;
}
}
+}
- # Compute all-pairs-shortest-paths on dist, which is the
- # actual distances between all LPs.
- #
- my $wialldists= $widists->APSP_Floyd_Warshall();
-
+sub yppedia_archs_chart_labels () {
# Assign archipelago labels to groups of islands
#
foreach my $label (@wiarchlabels) {
$wiccix2arch{$ccix}= $arch;
# print "$ccix $arch ::\n$desc\n";
}
+}
+sub yppedia_archs_fillbynearest() {
# Assign islands not labelled above to archipelagoes.
#
# We do this by, for each connected component (set of islands
next unless $ccs_useful[$targetccix];
foreach my $target ($wiarchs->
connected_component_by_index($targetccix)) {
+ next unless $widists->has_vertex($target);
foreach my $source (@sourcecc) {
- my $target_dist= $wialldists->path_length($target,$source);
+ my $target_dist= widist($target,$source);
next unless defined $target_dist;
next if $target_dist >= $best_dist;
$best_dist= $target_dist;
}
}
+sub yppedia_graph_shortest_paths () {
+ $wialldists= $widists->APSP_Floyd_Warshall();
+}
+
+sub widist ($$) {
+ my ($p,$q) = @_;
+ my $pl= $wialldists->path_length($p,$q);
+# die "$p $q" unless defined $pl;
+# my @pv= $wialldists->path_vertices($p,$q);
+# if (@pv == $pl) { return $pl; }
+# printf DEBUG "%-5s PATHLENGTH %-5s pl=%s pv=%s\n", $p,$q,$pl,join('|',@pv);
+ return $pl;
+}
+
sub winode2arch ($) {
my ($node) = @_;
my $ccix= $wiarchs->connected_component_by_vertex($node);
}
my $dbarch= $dbisland2arch{$island};
if ($wiarch ne $dbarch) {
- change("change archipelago from $dbarch to $wiarch".
+ change("archipelago change from $dbarch to $wiarch".
" for island $island");
}
}
next;
# We check arches of non-new islands above
}
- change("new island in $wiarch: $island");
+ change("island new in $wiarch: $island");
+ }
+ }
+}
+
+sub shortest_path_reduction ($$) {
+ my ($what,$g) = @_;
+ #
+ # Takes a graph $g (and a string for messages $what) and returns
+ # a new graph which is the miminal shortest path transient reduction
+ # of $g.
+ #
+ # We also check that the shortest path closure of the intended result
+ # is the same graph as the input. Thus the input must itself be
+ # a shortest path closure; if it isn't, we die.
+
+ my $proof=<<'END'; # way to make a big comment
+
+ Premises and definitions:
+
+ 1. F is an undirected weighted graph with positive edge weights.
+
+ 2. All graphs we will consider have the same vertices as F.
+
+ 3. G = Closure(F) is the graph of cliques whose edge weights
+ are the shortest paths in F, one clique for each connected
+ component in F.
+
+ 3a. |XY| for vertices X, Y is the weight of the edge XY in G.
+ If XY is not in G, |XY| is infinite.
+
+ 4. A `reduction' of G is a subgraph K of G such that Closure(K) = G.
+ The reduction is `minimal' if there is no strict subgraph K'
+ of K such that Closure(K') = G.
+
+ 5. Now each edge of G may be:
+ - `unnecessary': included in no minimal reductions of G.
+ - `essential': included in all minimal reductions of G.
+ - `contingent': included in some but not all.
+
+ 6. Consider for any edge AC between the vertices A and C,
+ whether there is any B such that |AB|+|BC| = |AC| ?
+ (There can be no B such that the sum < |AC| since that would
+ mean that |AC| wasn't equal to the shortest path length.)
+
+ 6a. No such B: AC is therefore the only shortest path from A to C
+ (since G is not a multigraph). AC is thus an essential edge.
+
+ 6b. Some such B: Call all such edges AC `questionable'.
+
+ 6c. Thus all edges are essential or questionable.
+
+ 7. Suppose AC is a shortest contingent edge. AC must be
+ questionable since it is not essential. Suppose it is
+ made questionable by the existence of B such that |AB|+|BC| =
+ |AC|. Consider AB and BC. Since |AB| and |BC| are positive,
+ |BC| and |AB| must be < |AC| ie AB and BC are shorter than AC.
+ Since AC is a shortest contingent edge, there must be shortest
+ paths in G for AB and BC consisting entirely of essential edges.
+
+ 8. Therefore it is always safe to remove AC since the paths
+ A..B and B..C will definitely still remain and provide a path
+ A..B..C with length |AB|+|BC| = |AC|.
+
+ 9. Thus AC is unnecessary, contradicting the assumption in 7.
+ There are therefore no shortest contingent edges, and
+ thus no contingent edges.
+
+ 10. We can construct a minimal reduction directly: for each edge
+ AC in G, search for a vertex B such that |AB|+|BC| = |AC|.
+ If we find none, AC is essential. If we find one then AC is
+ not essential and is therefore unnecessary.
+
+END
+
+ printf DEBUG "spr %s before %d\n", $what, scalar($g->edges());
+
+ my $result= Graph::Undirected->new();
+ foreach my $edge_ac ($g->edges()) {
+ my $edgename_ac= join ' .. ', @$edge_ac;
+ printf DEBUG "spr %s edge %s\n", $what, $edgename_ac;
+ my $w_ac= $g->get_edge_weight(@$edge_ac);
+ my $needed= 1;
+ foreach my $vertex_b ($g->vertices()) {
+ next if grep { $_ eq $vertex_b } @$edge_ac;
+ my $w_ab= $g->get_edge_weight($edge_ac->[0], $vertex_b);
+ next unless defined $w_ab;
+ next if $w_ab >= $w_ac;
+ my $w_bc= $g->get_edge_weight($vertex_b, $edge_ac->[1]);
+ next unless defined $w_ac;
+ next if $w_ab + $w_bc > $w_ac;
+ # found path
+ printf DEBUG "spr %s edge %s unnecessary %s\n",
+ $what, $edgename_ac, $vertex_b;
+ $needed= 0;
+ last;
+ }
+ if ($needed) {
+ printf DEBUG "spr %s edge %s essential\n", $what, $edgename_ac;
+ $result->add_weighted_edge(@$edge_ac,$w_ac);
+ }
+ }
+ printf DEBUG "spr %s result %d\n", $what, scalar($result->edges());
+
+ my $apsp= $result->APSP_Floyd_Warshall();
+ foreach my $ia (sort $g->vertices()) {
+ foreach my $ib (sort $g->vertices()) {
+ my $din= $g->get_edge_weight($ia,$ib);
+ my $dout= $apsp->path_length($ia,$ib);
+ $din= defined($din) ? $din : 'infinity';
+ $dout= defined($dout) ? $dout : 'infinity';
+ error("$what spr apsp discrepancy in=$din out=$dout".
+ " for $ia .. $ib")
+ if $din != $dout;
+ }
+ }
+ return $result;
+}
+
+sub yppedia_graph_spr () {
+ my $base= Graph::Undirected->new();
+ foreach my $na (sort keys %winode2island) {
+ my $ia= $winode2island{$na};
+ foreach my $nb (sort keys %winode2island) {
+ my $ib= $winode2island{$nb};
+ $base->add_weighted_edge($ia,$ib, widist($na,$nb));
+ }
+ }
+ $wispr= shortest_path_reduction('wi',$base);
+}
+
+sub compare_distances () {
+ foreach my $ia (sort keys %dbisland2arch) {
+ my $na= $wiisland2node{$ia};
+ next unless defined $na;
+ foreach my $ib (sort keys %dbisland2arch) {
+ next unless $ia le $ib; # do every pair only once
+ my $dbdist= $dbspr->get_edge_weight($ia,$ib);
+ my $widist= $wispr->get_edge_weight($ia,$ib);
+ next unless defined $dbdist || defined $widist;
+
+ if (!defined $widist) {
+ warning(sprintf "route delete %2d for %s .. %s",
+ $dbdist, $ia,$ib);
+ } elsif (!defined $dbdist) {
+ change(sprintf "route new %2d for %s .. %s",
+ $widist, $ia,$ib);
+ } elsif ($dbdist != $widist) {
+ change(sprintf "route change %2d to %2d for %s .. %s",
+ $dbdist, $widist, $ia,$ib);
+ }
}
}
}
parse_info_serverside();
+
+progress("reading database");
+
db_setocean($ocean);
db_connect();
-parse_yppedia_map();
-parse_database_map();
-process_yppedia_graphs();
-compare_island_lists();
+database_fetch_ocean();
+
+progress("computing database spr"); database_graph_spr();
+
+progress("reading yppedia chart"); yppedia_chart_parse();
+progress("adding shortcuts"); yppedia_graphs_add_shortcuts();
+progress("pruning boring vertices"); yppedia_graphs_prune_boring();
+progress("checking yppedia graphs"); yppedia_graphs_check();
+progress("setting archs from source-info"); yppedia_archs_sourceinfo();
+progress("computing shortest paths"); yppedia_graph_shortest_paths();
+progress("setting archs from labels"); yppedia_archs_chart_labels();
+progress("setting archs from nearby"); yppedia_archs_fillbynearest();
+progress("computing yppedia spr"); yppedia_graph_spr();
+
+progress("comparing islands"); compare_island_lists();
+progress("comparing distances"); compare_distances();
+
+print_messages();