remove some debugging statements
[scpubgit/stemmatology.git] / lib / Text / Tradition / Analysis.pm
index a6c3948..1a3e7b1 100644 (file)
@@ -5,10 +5,12 @@ use warnings;
 use Benchmark;
 use Encode qw/ encode_utf8 /;
 use Exporter 'import';
+use Graph;
 use JSON qw/ encode_json decode_json /;
 use LWP::UserAgent;
 use Text::Tradition;
 use Text::Tradition::Stemma;
+use TryCatch;
 
 use vars qw/ @EXPORT_OK /;
 @EXPORT_OK = qw/ run_analysis group_variants analyze_variant_location wit_stringify /;
@@ -55,6 +57,8 @@ is 0 (i.e. the first).
 =item * merge_types - Specify a list of relationship types, where related readings 
 should be treated as identical for the purposes of analysis.
 
+=item * exclude_type1 - Exclude those ranks whose groupings have only type-1 variants.
+
 =back
 
 =begin testing
@@ -101,16 +105,31 @@ my %expected_genealogical = (
 );
 
 my $data = run_analysis( $tradition );
+my $c = $tradition->collation;
 foreach my $row ( @{$data->{'variants'}} ) {
        # Account for rows that used to be "not useful"
        unless( exists $expected_genealogical{$row->{'id'}} ) {
                $expected_genealogical{$row->{'id'}} = 1;
        }
-       is( $row->{'genealogical'}, $expected_genealogical{$row->{'id'}}, 
+       my $gen_bool = $row->{'genealogical'} ? 1 : 0;
+       is( $gen_bool, $expected_genealogical{$row->{'id'}}, 
                "Got correct genealogical flag for row " . $row->{'id'} );
+       # Check that we have the right row with the right groups
+       my $rank = $row->{'id'};
+       foreach my $rdghash ( @{$row->{'readings'}} ) {
+               # Skip 'readings' that aren't really
+               next unless $c->reading( $rdghash->{'readingid'} );
+               # Check the rank
+               is( $c->reading( $rdghash->{'readingid'} )->rank, $rank, 
+                       "Got correct reading rank" );
+               # Check the witnesses
+               my @realwits = sort $c->reading_witnesses( $rdghash->{'readingid'} );
+               my @sgrp = sort @{$rdghash->{'group'}};
+               is_deeply( \@sgrp, \@realwits, "Reading analyzed with correct groups" );
+       }
 }
-is( $data->{'conflict_count'}, 34, "Got right conflict count" );
 is( $data->{'variant_count'}, 58, "Got right total variant number" );
+# TODO Make something meaningful of conflict count, maybe test other bits
 
 =end testing
 
@@ -126,11 +145,12 @@ sub run_analysis {
 
        # Get the stemma        
        my $stemma = $tradition->stemma( $stemma_id );
-       # Figure out which witnesses we are working with
+
+       # Figure out which witnesses we are working with - that is, the ones that
+       # appear both in the stemma and in the tradition. All others are 'lacunose'
+       # for our purposes.
        my @lacunose = $stemma->hypotheticals;
        my @tradition_wits = map { $_->sigil } $tradition->witnesses;
-       map { push( @tradition_wits, $_->sigil."_ac" ) if $_->is_layered } 
-               $tradition->witnesses;
        push( @lacunose, _symmdiff( [ $stemma->witnesses ], \@tradition_wits ) );
 
        # Find and mark 'common' ranks for exclusion, unless they were
@@ -145,33 +165,68 @@ sub run_analysis {
        
        # Group the variants to send to the solver
        my @groups;
+       my @use_ranks;
        my %lacunae;
+       my $moved = {};
        foreach my $rank ( @ranks ) {
                my $missing = [ @lacunose ];
-               push( @groups, group_variants( $tradition, $rank, $missing, \@collapse ) );
+               my $rankgroup = group_variants( $tradition, $rank, $missing, $moved, \@collapse );
+               # Filter out any empty rankgroups 
+               # (e.g. from the later rank for a transposition)
+               next unless keys %$rankgroup;
+               if( $opts{'exclude_type1'} ) {
+                       # Check to see whether this is a "useful" group.
+                       my( $rdgs, $grps ) = _useful_variant( $rankgroup, 
+                               $stemma->graph, $c->ac_label );
+                       next unless @$rdgs;
+               }
+               push( @use_ranks, $rank );
+               push( @groups, $rankgroup );
                $lacunae{$rank} = $missing;
        }
-       
-       # Parse the answer
+       # Run the solver
        my $answer = solve_variants( $stemma, @groups );
 
        # Do further analysis on the answer
        my $conflict_count = 0;
-       foreach my $idx ( 0 .. $#ranks ) {
+       my $aclabel = $c->ac_label;
+       foreach my $idx ( 0 .. $#use_ranks ) {
                my $location = $answer->{'variants'}->[$idx];
                # Add the rank back in
-               $location->{'id'} = $ranks[$idx];
-               # Add the lacunae back in
-               $location->{'missing'} = $lacunae{$ranks[$idx]};
+               my $rank = $use_ranks[$idx];
+               $location->{'id'} = $rank;
+               # Note what our lacunae are
+               my %lmiss;
+               map { $lmiss{$_} = 1 } @{$lacunae{$use_ranks[$idx]}};
+               $location->{'missing'} = [ keys %lmiss ];
+               
                # Run the extra analysis we need.
-               analyze_location( $tradition, $stemma->graph, $location );
-               # Add the reading text back in
+               analyze_location( $tradition, $stemma, $location, \%lmiss );
+
+               my @layerwits;
+               # Do the final post-analysis tidying up of the data.
                foreach my $rdghash ( @{$location->{'readings'}} ) {
                        $conflict_count++ 
                                if exists $rdghash->{'conflict'} && $rdghash->{'conflict'};
+                       # Add the reading text back in, setting display value as needed
                        my $rdg = $c->reading( $rdghash->{'readingid'} );
-                       $rdghash->{'text'} = $rdg ? $rdg->text : $rdghash->{'readingid'};
+                       if( $rdg ) {
+                               $rdghash->{'text'} = $rdg->text . 
+                                       ( $rdg->rank == $rank ? '' : ' [' . $rdg->rank . ']' );
+                       }
+                       # Remove lacunose witnesses from this reading's list now that the
+                       # analysis is done 
+                       my @realgroup;
+                       map { push( @realgroup, $_ ) unless $lmiss{$_} } @{$rdghash->{'group'}};
+                       $rdghash->{'group'} = \@realgroup;
+                       # Note any layered witnesses that appear in this group
+                       foreach( @realgroup ) {
+                               if( $_ =~ /^(.*)\Q$aclabel\E$/ ) {
+                                       push( @layerwits, $1 );
+                               }
+                       }
                }
+               $location->{'layerwits'} = \@layerwits if @layerwits;
        }
        $answer->{'conflict_count'} = $conflict_count;
        
@@ -183,59 +238,195 @@ sub run_analysis {
 Groups the variants at the given $rank of the collation, treating any
 relationships in @merge_relationship_types as equivalent.  $lacunose should
 be a reference to an array, to which the sigla of lacunose witnesses at this 
-rank will be appended.
+rank will be appended; $transposed should be a reference to a hash, wherein
+the identities of transposed readings and their relatives will be stored.
 
-Returns two ordered lists $readings, $groups, where $readings->[$n] is attested
-by the witnesses listed in $groups->[$n].
+Returns a hash $group_readings where $rdg is attested by the witnesses listed 
+in $group_readings->{$rdg}.
 
 =cut
 
 # Return group_readings, groups, lacunose
 sub group_variants {
-       my( $tradition, $rank, $lacunose, $collapse ) = @_;
+       my( $tradition, $rank, $lacunose, $transposed, $collapse ) = @_;
        my $c = $tradition->collation;
        my $aclabel = $c->ac_label;
+       my $table = $c->alignment_table;
        # Get the alignment table readings
        my %readings_at_rank;
-       my @gap_wits;
-       foreach my $tablewit ( @{$c->alignment_table->{'alignment'}} ) {
+       my %is_lacunose; # lookup table for witnesses not in stemma
+       map { $is_lacunose{$_} = 1; $is_lacunose{$_.$aclabel} = 1 } @$lacunose;
+       my @check_for_gaps;
+       my %moved_wits;
+       my $has_transposition;
+       foreach my $tablewit ( @{$table->{'alignment'}} ) {
                my $rdg = $tablewit->{'tokens'}->[$rank-1];
                my $wit = $tablewit->{'witness'};
-               $wit =~ s/^(.*)\Q$aclabel\E$/${1}_ac/;
+               # Exclude the witness if it is "lacunose" which if we got here
+               # means "not in the stemma".
+               next if $is_lacunose{$wit};
+               # Note if the witness is actually in a lacuna
                if( $rdg && $rdg->{'t'}->is_lacuna ) {
-                       _add_to_witlist( $wit, $lacunose, '_ac' );
+                       _add_to_witlist( $wit, $lacunose, $aclabel );
+               # Otherwise the witness either has a positive reading...
                } elsif( $rdg ) {
-                       $readings_at_rank{$rdg->{'t'}->text} = $rdg->{'t'};
+                       # If the reading has been counted elsewhere as a transposition, ignore it.
+                       if( $transposed->{$rdg->{'t'}->id} ) {
+                               # TODO Does this cope with three-way transpositions?
+                               map { $moved_wits{$_} = 1 } @{$transposed->{$rdg->{'t'}->id}};
+                               next;
+                       }
+                       # Otherwise, record it...
+                       $readings_at_rank{$rdg->{'t'}->id} = $rdg->{'t'};
+                       # ...and grab any transpositions, and their relations.
+                       my @transp = grep { $_->rank != $rank } $rdg->{'t'}->related_readings();
+                       foreach my $trdg ( @transp ) {
+                               next if exists $readings_at_rank{$trdg->id};
+                               $has_transposition = 1;
+                               my @affected_wits = _table_witnesses( 
+                                       $table, $trdg, \%is_lacunose, $aclabel );
+                               next unless @affected_wits;
+                               map { $moved_wits{$_} = 1 } @affected_wits;
+                               $transposed->{$trdg->id} = 
+                                       [ _table_witnesses( $table, $rdg->{'t'}, \%is_lacunose, $aclabel ) ];
+                               $readings_at_rank{$trdg->id} = $trdg;
+                       }
+               # ...or it is empty, ergo a gap.
                } else {
-                       _add_to_witlist( $wit, \@gap_wits, '_ac' );
+                       _add_to_witlist( $wit, \@check_for_gaps, $aclabel );
                }
        }
-       
+       my @gap_wits;
+       map { _add_to_witlist( $_, \@gap_wits, $aclabel ) 
+               unless $moved_wits{$_} } @check_for_gaps;
        # Group the readings, collapsing groups by relationship if needed
-       my %grouped_readings;
-       foreach my $rdg ( sort { $b->witnesses <=> $a->witnesses } values %readings_at_rank ) {
+       my $grouped_readings = {};
+       foreach my $rdg ( values %readings_at_rank ) {
                # Skip readings that have been collapsed into others.
-               next if exists $grouped_readings{$rdg->id} && !$grouped_readings{$rdg->id};
-               my @wits = $rdg->witnesses;
-               map { s/\Q$aclabel\E$/_ac/ } @wits;
-               if( $collapse ) {
+               next if exists $grouped_readings->{$rdg->id} 
+                       && $grouped_readings->{$rdg->id} eq 'COLLAPSE';
+               # Get the witness list, including from readings collapsed into this one.
+               my @wits = _table_witnesses( $table, $rdg, \%is_lacunose, $aclabel );
+               if( $collapse && @$collapse ) {
                        my $filter = sub { my $r = $_[0]; grep { $_ eq $r->type } @$collapse; };
                        foreach my $other ( $rdg->related_readings( $filter ) ) {
-                               my @otherwits = $other->witnesses;
-                               map { s/\Q$aclabel\E$/_ac/ } @otherwits;
+                               my @otherwits = _table_witnesses( 
+                                       $table, $other, \%is_lacunose, $aclabel );
                                push( @wits, @otherwits );
-                               $grouped_readings{$other->id} = 0;
+                               $grouped_readings->{$other->id} = 'COLLAPSE';
                        }
                }
-               $grouped_readings{$rdg->id} = \@wits;   
+               $grouped_readings->{$rdg->id} = \@wits;
        }
-       $grouped_readings{'(omitted)'} = \@gap_wits if @gap_wits;
+       $grouped_readings->{'(omitted)'} = \@gap_wits if @gap_wits;
        # Get rid of our collapsed readings
-       map { delete $grouped_readings{$_} unless $grouped_readings{$_} } 
-               keys %grouped_readings 
+       map { delete $grouped_readings->{$_} if $grouped_readings->{$_} eq 'COLLAPSE' } 
+               keys %$grouped_readings 
                if $collapse;
+               
+       # If something was transposed, check the groups for doubled-up readings
+       if( $has_transposition ) {
+               # print STDERR "Group for rank $rank:\n";
+               # map { print STDERR "\t$_: " . join( ' ' , @{$grouped_readings->{$_}} ) . "\n" } 
+               #       keys %$grouped_readings;
+               _check_transposed_consistency( $c, $rank, $transposed, $grouped_readings );
+       }
        
-       return \%grouped_readings;
+       # Return the result
+       return $grouped_readings;
+}
+
+# Helper function to query the alignment table for all witnesses (a.c. included)
+# that have a given reading at its rank.
+sub _table_witnesses {
+       my( $table, $trdg, $lacunose, $aclabel ) = @_;
+       my $tableidx = $trdg->rank - 1;
+       my @has_reading;
+       foreach my $row ( @{$table->{'alignment'}} ) {
+               my $wit = $row->{'witness'};
+               next if $lacunose->{$wit};
+               my $rdg = $row->{'tokens'}->[$tableidx];
+               next unless exists $rdg->{'t'} && defined $rdg->{'t'};
+               _add_to_witlist( $wit, \@has_reading, $aclabel )
+                       if $rdg->{'t'}->id eq $trdg->id;
+       }
+       return @has_reading;
+}
+
+# Helper function to ensure that X and X a.c. never appear in the same list.
+sub _add_to_witlist {
+       my( $wit, $list, $acstr ) = @_;
+       my %inlist;
+       my $idx = 0;
+       map { $inlist{$_} = $idx++ } @$list;
+       if( $wit =~ /^(.*)\Q$acstr\E$/ ) {
+               my $acwit = $1;
+               unless( exists $inlist{$acwit} ) {
+                       push( @$list, $acwit.$acstr );
+               }
+       } else {
+               if( exists( $inlist{$wit.$acstr} ) ) {
+                       # Replace the a.c. version with the main witness
+                       my $i = $inlist{$wit.$acstr};
+                       $list->[$i] = $wit;
+               } else {
+                       push( @$list, $wit );
+               }
+       }
+}
+
+sub _check_transposed_consistency {
+       my( $c, $rank, $transposed, $groupings ) = @_;
+       my %seen_wits;
+       my %thisrank;
+       # Note which readings are actually at this rank, and which witnesses
+       # belong to which reading.
+       foreach my $rdg ( keys %$groupings ) {
+               my $rdgobj = $c->reading( $rdg );
+               # Count '(omitted)' as a reading at this rank
+               $thisrank{$rdg} = 1 if !$rdgobj || $rdgobj->rank == $rank;
+               map { push( @{$seen_wits{$_}}, $rdg ) } @{$groupings->{$rdg}};
+       }
+       # Our work is done if we have no witness belonging to more than one
+       # reading.
+       my @doubled = grep { scalar @{$seen_wits{$_}} > 1 } keys %seen_wits;
+       return unless @doubled;
+       # If we have a symmetric related transposition, drop the non-rank readings.
+       if( @doubled == scalar keys %seen_wits ) {
+               foreach my $rdg ( keys %$groupings ) {
+                       if( !$thisrank{$rdg} ) {
+                               my $groupstr = wit_stringify( $groupings->{$rdg} );
+                               my ( $matched ) = grep { $groupstr eq wit_stringify( $groupings->{$_} ) }
+                                       keys %thisrank;
+                               delete $groupings->{$rdg};
+                               # If we found a group match, assume there is a symmetry happening.
+                               # TODO think more about this
+                               # print STDERR "*** Deleting symmetric reading $rdg\n";
+                               unless( $matched ) {
+                                       delete $transposed->{$rdg};
+                                       warn "Found problem in evident symmetry with reading $rdg";
+                               }
+                       }
+               }
+       # Otherwise 'unhook' the transposed reading(s) that have duplicates.
+       } else {
+               foreach my $dup ( @doubled ) {
+                       foreach my $rdg ( @{$seen_wits{$dup}} ) {
+                               next if $thisrank{$rdg};
+                               next unless exists $groupings->{$rdg};
+                               # print STDERR "*** Deleting asymmetric doubled-up reading $rdg\n";
+                               delete $groupings->{$rdg};
+                               delete $transposed->{$rdg};
+                       }
+               }
+               # and put any now-orphaned readings into an 'omitted' reading.
+               foreach my $wit ( keys %seen_wits ) {
+                       unless( grep { exists $groupings->{$_} } @{$seen_wits{$wit}} ) {
+                               $groupings->{'(omitted)'} = [] unless exists $groupings->{'(omitted)'};
+                               _add_to_witlist( $wit, $groupings->{'(omitted)'}, $c->ac_label );
+                       }
+               }
+       }
 }
 
 =head2 solve_variants( $graph, @groups ) 
@@ -257,54 +448,113 @@ The answer has the form
 
 sub solve_variants {
        my( $stemma, @groups ) = @_;
-
-       # Make the json with stemma + groups
-       my $jsonstruct = { 'graph' => $stemma->editable( ' ' ), 'groupings' => [] };
-       foreach my $ghash ( @groups ) {
+       my $aclabel = $stemma->collation->ac_label;
+
+       # Filter the groups down to distinct groups, and work out what graph
+       # should be used in the calculation of each group. We want to send each
+       # distinct problem to the solver only once.
+       # We need a whole bunch of lookup tables for this.
+       my $index_groupkeys = {};       # Save the order of readings
+       my $group_indices = {};         # Save the indices that have a given grouping
+       my $graph_problems = {};        # Save the groupings for the given graph
+
+       foreach my $idx ( 0..$#groups ) {
+               my $ghash = $groups[$idx];
                my @grouping;
-               foreach my $k ( sort keys %$ghash ) {
-                       push( @grouping, $ghash->{$k} );
+               # Sort the groupings from big to little, and scan for a.c. witnesses
+               # that would need an extended graph.
+               my @acwits;   # note which AC witnesses crop up at this rank
+               my @idxkeys = sort { scalar @{$ghash->{$b}} <=> scalar @{$ghash->{$a}} }
+                       keys %$ghash;
+               foreach my $rdg ( @idxkeys ) {
+                       my @sg = sort @{$ghash->{$rdg}};
+                       push( @acwits, grep { $_ =~ /\Q$aclabel\E$/ } @sg );
+                       push( @grouping, \@sg );
+               }
+               # Save the reading order
+               $index_groupkeys->{$idx} = \@idxkeys;
+               
+               # Now associate the distinct group with this index
+               my $gstr = wit_stringify( \@grouping );
+               push( @{$group_indices->{$gstr}}, $idx );
+               
+               # Finally, add the group to the list to be calculated for this graph.
+               map { s/\Q$aclabel\E$// } @acwits;
+               my $graph;
+               try {
+                       $graph = $stemma->extend_graph( \@acwits );
+               } catch {
+                       die "Unable to extend graph with @acwits";
+               }
+               unless( exists $graph_problems->{"$graph"} ) {
+                       $graph_problems->{"$graph"} = { 'object' => $graph, 'groups' => [] };
                }
-               push( @{$jsonstruct->{'groupings'}}, \@grouping );
+               push( @{$graph_problems->{"$graph"}->{'groups'}}, \@grouping );
        }
-       my $json = encode_json( $jsonstruct );
-
-       # Send it off and get the result
+       
+       ## For each distinct graph, send its groups to the solver.
        my $solver_url = 'http://byzantini.st/cgi-bin/graphcalc.cgi';
        my $ua = LWP::UserAgent->new();
-       my $resp = $ua->post( $solver_url, 'Content-Type' => 'application/json', 
-                                                 'Content' => $json );
-                                                 
-       my $answer;
-       if( $resp->is_success ) {
-               $answer = decode_json( $resp->content );
-       } else {
-               # Fall back to the old method.
-               warn "IDP solver returned " . $resp->status_line . " / " . $resp->content
-                       . "; falling back to perl method";
-               $answer = perl_solver( $stemma, @{$jsonstruct->{'groupings'}} );
-       }
-       
-       # Fold the result back into what we know about the groups.
-       my $variants = [];
+       ## Witness map is a HACK to get around limitations in node names from IDP
+       my $witness_map = {};
+       ## Variables to store answers as they come back
+       my $variants = [ ( undef ) x ( scalar keys %$index_groupkeys ) ];
        my $genealogical = 0;
-       foreach my $idx ( 0 .. $#groups ) {
-               my( $calc_groups, $result ) = @{$answer->[$idx]};
-               $genealogical++ if $result;
-               my $input_group = $groups[$idx];
-               foreach my $k ( sort keys %$input_group ) {
-                       my $cg = shift @$calc_groups;
-                       $input_group->{$k} = $cg;
+       foreach my $graphkey ( keys %$graph_problems ) {
+               my $graph = $graph_problems->{$graphkey}->{'object'};
+               my $groupings = $graph_problems->{$graphkey}->{'groups'};
+               my $json = encode_json( _safe_wit_strings( $graph, $stemma->collation,
+                       $groupings, $witness_map ) );
+               # Send it off and get the result
+               #print STDERR "Sending request: $json\n";
+               my $resp = $ua->post( $solver_url, 'Content-Type' => 'application/json', 
+                                                         'Content' => $json );                                                   
+               my $answer;
+               my $used_idp;
+               if( $resp->is_success ) {
+                       $answer = _desanitize_names( decode_json( $resp->content ), $witness_map );
+                       $used_idp = 1;
+               } else {
+                       # Fall back to the old method.
+                       warn "IDP solver returned " . $resp->status_line . " / " . $resp->content
+                               . "; falling back to perl method";
+                       $answer = perl_solver( $graph, @$groupings );
                }
-               my $vstruct = { 
-                       'genealogical' => $result,
-                       'readings' => [],
-               };
-               foreach my $k ( keys %$input_group ) {
-                       push( @{$vstruct->{'readings'}}, 
-                                 { 'readingid' => $k, 'group' => $input_group->{$k}} );
+               ## The answer is the evaluated groupings, plus a boolean for whether
+               ## they were genealogical.  Reconstruct our original groups.
+               foreach my $gidx ( 0 .. $#{$groupings} ) {
+                       my( $calc_groups, $result ) = @{$answer->[$gidx]};
+                       if( $result ) {
+                               $genealogical++;
+                               # Prune the calculated groups, in case the IDP solver failed to.
+                               if( $used_idp ) {
+                                       my @pruned_groups;
+                                       foreach my $cg ( @$calc_groups ) {
+                                               # This is a little wasteful but the path of least
+                                               # resistance. Send both the stemma, which knows what
+                                               # its hypotheticals are, and the actual graph used.
+                                               my @pg = _prune_group( $cg, $stemma, $graph );
+                                               push( @pruned_groups, \@pg );
+                                       }
+                                       $calc_groups = \@pruned_groups;
+                               }
+                       }
+                       # Retrieve the key for the original group that went to the solver
+                       my $input_group = wit_stringify( $groupings->[$gidx] );
+                       foreach my $oidx ( @{$group_indices->{$input_group}} ) {
+                               my @readings = @{$index_groupkeys->{$oidx}};
+                               my $vstruct = {
+                                       'genealogical' => $result,
+                                       'readings' => [],
+                               };
+                               foreach my $ridx ( 0 .. $#readings ) {
+                                       push( @{$vstruct->{'readings'}},
+                                               { 'readingid' => $readings[$ridx],
+                                                 'group' => $calc_groups->[$ridx] } );
+                               }
+                               $variants->[$oidx] = $vstruct;
+                       }
                }
-               push( @$variants, $vstruct );
        }
        
        return { 'variants' => $variants, 
@@ -312,6 +562,93 @@ sub solve_variants {
                         'genealogical_count' => $genealogical };
 }
 
+#### HACKERY to cope with IDP's limited idea of what a node name looks like ###
+
+sub _safe_wit_strings {
+       my( $graph, $c, $groupings, $witness_map ) = @_;
+       # Parse the graph we were given into a stemma.
+       my $safegraph = Graph->new();
+       # Convert the graph to a safe representation and store the conversion.
+       foreach my $n ( $graph->vertices ) {
+               my $sn = _safe_witstr( $n );
+               if( exists $witness_map->{$sn} ) {
+                       warn "Ambiguous stringification $sn for $n and " . $witness_map->{$sn}
+                               if $witness_map->{$sn} ne $n;
+               } else {
+                       $witness_map->{$sn} = $n;
+               }
+               $safegraph->add_vertex( $sn );
+               $safegraph->set_vertex_attributes( $sn, 
+                       $graph->get_vertex_attributes( $n ) );
+       }
+       foreach my $e ( $graph->edges ) {
+               my @safe_e = ( _safe_witstr( $e->[0] ), _safe_witstr( $e->[1] ) );
+               $safegraph->add_edge( @safe_e );
+       }
+       my $safe_stemma = Text::Tradition::Stemma->new( 
+               'collation' => $c, 'graph' => $safegraph );
+               
+       # Now convert the witness groupings to a safe representation.
+       my $safe_groupings = [];
+       foreach my $grouping ( @$groupings ) {
+               my $safe_grouping = [];
+               foreach my $group ( @$grouping ) {
+                       my $safe_group = [];
+                       foreach my $n ( @$group ) {
+                               my $sn = _safe_witstr( $n );
+                               warn "Ambiguous stringification $sn for $n and " . $witness_map->{$sn}
+                                       if exists $witness_map->{$sn} && $witness_map->{$sn} ne $n;
+                               $witness_map->{$sn} = $n;
+                               push( @$safe_group, $sn );
+                       }
+                       push( @$safe_grouping, $safe_group );
+               }
+               push( @$safe_groupings, $safe_grouping );
+       }
+       
+       # Return it all in the struct we expect.  We have stored the reductions
+       # in the $witness_map that we were passed.
+       return { 'graph' => $safe_stemma->editable( { 'linesep' => ' ' } ), 
+                        'groupings' => $safe_groupings };
+}
+
+sub _safe_witstr {
+       my $witstr = shift;
+       $witstr =~ s/\s+/_/g;
+       $witstr =~ s/[^\w\d-]//g;
+       return $witstr;
+}
+
+sub _desanitize_names {
+       my( $jsonstruct, $witness_map ) = @_;
+       my $result = [];
+       foreach my $grouping ( @$jsonstruct ) {
+               my $real_grouping = [];
+               foreach my $element ( @$grouping ) {
+                       if( ref( $element ) eq 'ARRAY' ) {
+                               # it's the groupset.
+                               my $real_groupset = [];
+                               foreach my $group ( @$element ) {
+                                       my $real_group = [];
+                                       foreach my $n ( @$group ) {
+                                               my $rn = $witness_map->{$n};
+                                               push( @$real_group, $rn );
+                                       }
+                                       push( @$real_groupset, $real_group );
+                               }
+                               push( @$real_grouping, $real_groupset );
+                       } else {
+                               # It is the boolean, not actually a group.
+                               push( @$real_grouping, $element );
+                       }
+               }
+               push( @$result, $real_grouping );
+       }
+       return $result;
+}
+
+### END HACKERY ###
+
 =head2 analyze_location ( $tradition, $graph, $location_hash )
 
 Given the tradition, its stemma graph, and the solution from the graph solver,
@@ -321,22 +658,52 @@ conflict, reading_parents, independent_occurrence, followed, not_followed, and f
 =cut
 
 sub analyze_location {
-       my ( $tradition, $graph, $variant_row ) = @_;
+       my ( $tradition, $stemma, $variant_row, $lacunose ) = @_;
+       my $c = $tradition->collation;
        
        # Make a hash of all known node memberships, and make the subgraphs.
        my $contig = {};
        my $reading_roots = {};
        my $subgraph = {};
+       my $acstr = $c->ac_label;
+       my @acwits;
+       $DB::single = 1 if $variant_row->{id} == 87;
+       # Note which witnesses positively belong to which group
     foreach my $rdghash ( @{$variant_row->{'readings'}} ) {
        my $rid = $rdghash->{'readingid'};
-               map { $contig->{$_} = $rid } @{$rdghash->{'group'}};
-        
+       foreach my $wit ( @{$rdghash->{'group'}} ) {
+               $contig->{$wit} = $rid;
+           if( $wit =~ /^(.*)\Q$acstr\E$/ ) {
+               push( @acwits, $1 );
+           }
+       }
+       }
+       
+       # Get the actual graph we should work with
+       my $graph;
+       try {
+               $graph = @acwits ? $stemma->extend_graph( \@acwits ) : $stemma->graph;
+       } catch {
+               die "Could not extend graph with a.c. witnesses @acwits";
+       }
+       
+       # Now, armed with that knowledge, make a subgraph for each reading
+       # and note the root(s) of each subgraph.
+       foreach my $rdghash( @{$variant_row->{'readings'}} ) {
+       my $rid = $rdghash->{'readingid'};
+        my %rdgwits;
         # Make the subgraph.
         my $part = $graph->copy;
-               my %these_vertices;
-               map { $these_vertices{$_} = 1 } @{$rdghash->{'group'}};
-               $part->delete_vertices( grep { !$these_vertices{$_} } $part->vertices );
+        my @todelete = grep { exists $contig->{$_} && $contig->{$_} ne $rid }
+               keys %$contig;
+        $part->delete_vertices( @todelete );
+        _prune_subtree( $part, $lacunose );
                $subgraph->{$rid} = $part;
+               # Record the remaining lacunose nodes as part of this group, if
+               # we are dealing with a non-genealogical reading.
+               unless( $variant_row->{'genealogical'} ) {
+                       map { $contig->{$_} = $rid } $part->vertices;
+               }
                # Get the reading roots.
                map { $reading_roots->{$_} = $rid } $part->predecessorless_vertices;
        }
@@ -345,18 +712,16 @@ sub analyze_location {
     # non-followed/unknown values for each reading.  Also figure out the
     # reading's evident parent(s).
     foreach my $rdghash ( @{$variant_row->{'readings'}} ) {
-       # Group string key - TODO do we need this?
-        my $gst = wit_stringify( $rdghash->{'group'} );
         my $rid = $rdghash->{'readingid'};
         # Get the subgraph
         my $part = $subgraph->{$rid};
         
         # Start figuring things out.  
-        my @roots = $part->predecessorless_vertices;
-        $rdghash->{'independent_occurrence'} = scalar @roots;
+        my @roots = grep { $reading_roots->{$_} eq $rid } keys %$reading_roots;
+        $rdghash->{'independent_occurrence'} = \@roots;
         $rdghash->{'followed'} = scalar( $part->vertices ) - scalar( @roots );
         # Find the parent readings, if any, of this reading.
-        my %rdgparents;
+        my $rdgparents = {};
         foreach my $wit ( @roots ) {
                # Look in the main stemma to find this witness's extant or known-reading
                # immediate ancestor(s), and look up the reading that each ancestor olds.
@@ -366,7 +731,7 @@ sub analyze_location {
                                foreach my $wparent( @check ) {
                                        my $preading = $contig->{$wparent};
                                        if( $preading ) {
-                                               $rdgparents{$preading} = 1;
+                                               $rdgparents->{$preading} = 1;
                                        } else {
                                                push( @next, $graph->predecessors( $wparent ) );
                                        }
@@ -374,7 +739,25 @@ sub analyze_location {
                                @check = @next;
                        }
                }
-               $rdghash->{'reading_parents'} = [ keys %rdgparents ];
+               foreach my $p ( keys %$rdgparents ) {
+                       # Resolve the relationship of the parent to the reading, and
+                       # save it in our hash.
+                       my $pobj = $c->reading( $p );
+                       my $relation;
+                       my $prep = $pobj ? $pobj->id . ' (' . $pobj->text . ')' : $p;
+                       if( $pobj ) {
+                               my $rel = $c->get_relationship( $p, $rdghash->{readingid} );
+                               if( $rel ) {
+                                       $relation = { type => $rel->type };
+                                       if( $rel->has_annotation ) {
+                                               $relation->{'annotation'} = $rel->annotation;
+                                       }
+                               }
+                       }       
+                       $rdgparents->{$p} = { 'label' => $prep, 'relation' => $relation };
+               }
+                       
+               $rdghash->{'reading_parents'} = $rdgparents;
                
                # Find the number of times this reading was altered, and the number of
                # times we're not sure.
@@ -425,8 +808,7 @@ possibly with the addition of hypothetical readings.
 =cut
 
 sub perl_solver {
-       my( $stemma, @groups ) = @_;
-       my $graph = $stemma->graph;
+       my( $graph, @groups ) = @_;
        my @answer;
        foreach my $g ( @groups ) {
                push( @answer, _solve_variant_location( $graph, $g ) );
@@ -472,7 +854,7 @@ sub _solve_variant_location {
                        # that implicitly later.
                        foreach my $root ( @roots ) {
                                # Prune the tree to get rid of extraneous hypotheticals.
-                               $root = _prune_subtree( $part, $root, $contig );
+                               $root = _prune_subtree_old( $part, $root, $contig );
                                next unless $root;
                                # Save this root for our group.
                                push( @group_roots, $root );
@@ -604,7 +986,48 @@ sub _solve_variant_location {
     return $variant_row;
 }
 
+sub _prune_group {
+       my( $group, $stemma, $graph ) = @_;
+       my $lacunose = {};
+       map { $lacunose->{$_} = 1 } $stemma->hypotheticals;
+       map { $lacunose->{$_} = 0 } @$group;
+       # Make our subgraph
+       my $subgraph = $graph->copy;
+       map { $subgraph->delete_vertex( $_ ) unless exists $lacunose->{$_} }
+               $subgraph->vertices;
+       # ...and find the root.
+       # Now prune and return the remaining vertices.
+       _prune_subtree( $subgraph, $lacunose );
+       return $subgraph->vertices;
+}
+
 sub _prune_subtree {
+       my( $tree, $lacunose ) = @_;
+       
+       # Delete lacunose witnesses that have no successors
+    my @orphan_hypotheticals;
+    my $ctr = 0;
+    do {
+       die "Infinite loop on leaves" if $ctr > 100;
+       @orphan_hypotheticals = grep { $lacunose->{$_} } 
+               $tree->successorless_vertices;
+        $tree->delete_vertices( @orphan_hypotheticals );
+        $ctr++;
+    } while( @orphan_hypotheticals );
+       
+       # Delete lacunose roots that have a single successor
+       my @redundant_root;
+       $ctr = 0;
+       do {
+       die "Infinite loop on roots" if $ctr > 100;
+               @redundant_root = grep { $lacunose->{$_} && $tree->successors( $_ ) == 1 } 
+                       $tree->predecessorless_vertices;
+               $tree->delete_vertices( @redundant_root );
+               $ctr++;
+       } while( @redundant_root );
+}
+
+sub _prune_subtree_old {
     my( $tree, $root, $contighash ) = @_;
     # First, delete hypothetical leaves / orphans until there are none left.
     my @orphan_hypotheticals = grep { ref( $contighash->{$_} ) } 
@@ -686,28 +1109,6 @@ sub wit_stringify {
     return join( ' / ', @gst );
 }
 
-# Helper function to ensure that X and X a.c. never appear in the same list.
-sub _add_to_witlist {
-       my( $wit, $list, $acstr ) = @_;
-       my %inlist;
-       my $idx = 0;
-       map { $inlist{$_} = $idx++ } @$list;
-       if( $wit =~ /^(.*)\Q$acstr\E$/ ) {
-               my $acwit = $1;
-               unless( exists $inlist{$acwit} ) {
-                       push( @$list, $acwit.$acstr );
-               }
-       } else {
-               if( exists( $inlist{$wit.$acstr} ) ) {
-                       # Replace the a.c. version with the main witness
-                       my $i = $inlist{$wit.$acstr};
-                       $list->[$i] = $wit;
-               } else {
-                       push( @$list, $wit );
-               }
-       }
-}
-
 sub _symmdiff {
        my( $lista, $listb ) = @_;
        my %union;