From b385228969382185afee33d0661790b2831ac6c1 Mon Sep 17 00:00:00 2001
From: Patrick Simianer <p@simianer.de>
Date: Tue, 20 May 2014 14:40:55 +0200
Subject: intersect2 correct & fast (ok, at least not impossibly slow)

---
 README.md       |   1 +
 example/grammar |   5 +-
 grammar.rb      |  24 ++++--
 intersect.rb    |  47 +++++++-----
 intersect1.rb   | 221 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 intersect2.rb   | 176 ++++++++++++++++++++++++++++++++++++++++++++
 6 files changed, 443 insertions(+), 31 deletions(-)
 create mode 100644 intersect1.rb
 create mode 100644 intersect2.rb

diff --git a/README.md b/README.md
index 5559e0d..30acc8b 100644
--- a/README.md
+++ b/README.md
@@ -1,2 +1,3 @@
 nothing to see here
+https://github.com/jweese/thrax/wiki/Glue-grammar
 
diff --git a/example/grammar b/example/grammar
index 1d72ce5..4a3c93c 100644
--- a/example/grammar
+++ b/example/grammar
@@ -1,8 +1,5 @@
 [S] ||| [NP,1] [VP,2] ||| [1] [2] ||| logp=0
-[S] ||| ich sah ein kleines haus ||| 
-[S] ||| ich [VP,2] ||| i [1] [2] ||| logp=0
-[S] ||| ich sah ein [NN,1] haus ||| i saw a [NN,1] house ||| logp=0
-[S] ||| ich [V,1] ein [NN,1] haus ||| i [1] a [2] house ||| logp=0
+[S] ||| ich sah ein [NN,1] |||
 [NP] ||| ich ||| i ||| logp=-0.5 use_i=1.0
 [NP] ||| ein [NN,1] ||| a [1] ||| logp=0 use_a=1.0
 [NN] ||| kleines haus ||| small house ||| logp=0 use_house=1
diff --git a/grammar.rb b/grammar.rb
index 8a08cc1..4183a8f 100644
--- a/grammar.rb
+++ b/grammar.rb
@@ -65,15 +65,23 @@ class Rule
 end
 
 class Grammar
-  attr_accessor :rules
+  attr_accessor :rules, :rewrite, :flat, :mixed
 
   def initialize fn
-    @rules = []
-    @glue_rules = []
-    ReadFile.readlines_strip(fn).each_with_index { |s,j|
+    @rules = []; @rewrite = []; @flat = []; @mixed = []
+    ReadFile.readlines_strip(fn).each_with_index { |s,i|
       STDERR.write '.'
-      STDERR.write "\n" if (j+1)%80==0
+      STDERR.write "\n" if (i+1)%80==0
       @rules << Rule.from_s(s)
+      if @rules.last.rhs.first.class == NT
+        @rewrite << @rules.last
+      else
+        if rules.last.arity == 0
+          @flat << @rules.last
+        else
+          @mixed << @rules.last
+        end
+      end
     }
     STDERR.write "\n"
   end
@@ -85,18 +93,18 @@ class Grammar
   end
 
   def add_glue_rules
-    # see https://github.com/jweese/thrax/wiki/Glue-grammar
     @rules.map { |r| r.lhs.symbol }.reject { |s| s=='S' }.uniq.each { |s|
       @rules << Rule.new(NT.new('S'), [NT.new(s)])
-      @glue_rules << @rules.last
+      @rewrite << @rules.last
       @rules << Rule.new(NT.new('S'), [NT.new('S'), NT.new('X')])
-      @glue_rules << @rules.last
+      @rewrite << @rules.last
     }
   end
 
   def add_pass_through_rules input
     input.each { |terminal|
       @rules << Rule.new(NT.new('X'), [T.new(terminal.word)])
+      @flat << @rules.last
     }
   end
 end
diff --git a/intersect.rb b/intersect.rb
index fa4a3bd..64b9696 100644
--- a/intersect.rb
+++ b/intersect.rb
@@ -68,7 +68,8 @@ end
 
 def init active_chart, passive_chart, grammar, input, n
   # pre-fill passive chart w/ 0-arity rules
-  grammar.rules.select { |r| r.rhs.first.class==T }.each { |r|
+  #grammar.rules.select { |r| r.rhs.first.class==T }.each { |r|
+  grammar.rules.select { |r| r.arity==0 }.each { |r|
     input.each_index.select { |i| input[i].word==r.rhs.first.word }.each { |j|
       k = 1
       if r.rhs.size > 1
@@ -86,16 +87,16 @@ def init active_chart, passive_chart, grammar, input, n
       end
       if k == r.rhs.size
         passive_chart.add(r, j, j+k, j+k, k)
-      else
-        (j+k).upto(n) { |l| active_chart.add r, j, l, j+k, k }
+      #else
+      #  (j+k).upto(n) { |l| active_chart.add r, j, l, j+k, k }
       end
     }
   }
   # seed active chart
-  s = grammar.rules.reject { |r| r.rhs.first.class!=NT }
-  visit(n, n, 1) { |i,j|
-    s.each { |r| active_chart.add(r, i, j, i) }
-  }
+  #s = grammar.rules.reject { |r| r.rhs.first.class!=NT }
+  #visit(n, n, 1) { |i,j|
+  #  s.each { |r| active_chart.add(r, i, j, i) }
+  #}
 end
 
 def scan item, passive_chart, input
@@ -111,11 +112,19 @@ def scan item, passive_chart, input
   end
 end
 
-def parse i, j, n, active_chart, passive_chart, input
-  active_chart.at(i,j).each { |active_item|
+def parse i, j, n, active_chart, passive_chart, input, grammar
+  grammar.rules.each { |r|
+    if r.rhs.first.class==T&&r.rhs.first.word==input[i].word
+      new_item = Item.new r
+      scan new_item, passive_chart, input
+    end
+  }
+  #active_chart.at(i,j).each { |active_item|
     1.upto(n) { |span|
       break if span==(j-i)
       i.upto(j-span) { |k|
+        STDERR.write " #{k},#{k+span}\n"
+        <<-DOC
         passive_chart.at(k, k+span).each { |passive_item|
           if active_item.rhs[active_item.dot].class==NT && passive_item.lhs.symbol == active_item.rhs[active_item.dot].symbol
             next if not active_item.span.right==passive_item.span.left
@@ -131,10 +140,10 @@ def parse i, j, n, active_chart, passive_chart, input
             end
           end
         }
+        DOC
       }
     }
-    true
-  }
+  #}
   # self-filling
   to_add_active = []
   to_add_passive = []
@@ -164,14 +173,14 @@ def preprocess s
 end
 
 def main
-  #input = preprocess 'ich sah ein kleines haus'
-  input = preprocess 'lebensmittel schuld an europäischer inflation'
+  input = preprocess 'ich sah ein kleines haus'
+  #input = preprocess 'lebensmittel schuld an europäischer inflation'
   #input = preprocess 'offizielle prognosen sind von nur 3 prozent ausgegangen , meldete bloomberg .'
   n = input.size
 
   puts 'reading grammar'
-  #g = Grammar.new 'example/grammar'
-  g = Grammar.new 'example/grammar.x'
+  g = Grammar.new 'example/grammar'
+  #g = Grammar.new 'example/grammar.x'
   #g = Grammar.new 'example/grammar.3.gz' # 4th segment of newstest2008
 
   puts 'adding glue rules'
@@ -187,12 +196,12 @@ def main
 
   puts 'parsing'
   visit(n, n, 1) { |i,j|
-    STDERR.write " span (#{i}, #{j})\n"
-    parse i, j, n, active_chart, passive_chart, input
+    STDERR.write "span (#{i}, #{j})\n"
+    parse i, j, n, active_chart, passive_chart, input, g
   }
 
-  puts "---\npassive chart"
-  visit(n, n, 0) { |i,j| puts "#{i},#{j}"; passive_chart.at(i,j).each { |item| puts ' '+item.to_s if item.span.left==i&&item.span.right==j }; puts }
+  #puts "---\npassive chart"
+  #visit(n, n, 0) { |i,j| puts "#{i},#{j}"; passive_chart.at(i,j).each { |item| puts ' '+item.to_s if item.span.left==i&&item.span.right==j }; puts }
 end
 
 
diff --git a/intersect1.rb b/intersect1.rb
new file mode 100644
index 0000000..fd465b0
--- /dev/null
+++ b/intersect1.rb
@@ -0,0 +1,221 @@
+#!/usr/bin/env ruby
+
+require_relative './grammar.rb'
+STDOUT.sync = true
+
+
+class Chart
+  attr_accessor :has
+
+  def initialize n
+    @m = []
+    (n+1).times {
+      _ = []
+      (n+1).times { _ << [] }
+      @m << _
+    }
+    @has = {}
+  end
+
+  def at i, j
+    @m[i][j]
+  end
+
+  def add rule_or_item, i, j, right, dot=0
+    item = Item.new(rule_or_item)
+    item.span.left = i
+    item.span.right = right
+    item.dot = dot
+    at(i, j) << item
+  end
+end
+
+class Span
+  attr_accessor :left, :right
+
+  def initialize left=nil, right=nil
+    @left = left
+    @right = right
+  end
+end
+
+class Item < Rule
+  attr_accessor :lhs, :rhs, :span, :dot
+
+  def initialize rule_or_item
+    @lhs = rule_or_item.lhs.dup
+    @rhs = rule_or_item.rhs.dup
+    if rule_or_item.class == Item
+      @span = Span.new rule_or_item.span.left, rule_or_item.span.right
+      @dot = rule_or_item.dot
+    else
+      @span = Span.new
+      @dot = 0
+    end
+  end
+
+  def to_s
+    "#{lhs} -> #{rhs.map{|i|i.to_s}.insert(@dot,'*').join ' '} [dot@#{@dot}] [arity=#{arity}] (#{@span.left}, #{@span.right})"
+  end
+end
+
+def visit n, depth, skip=0
+  (depth-skip).times { |i|
+    i += skip
+    0.upto(n-(i+1)) { |j|
+      yield j, j+i+1
+    }
+  }
+end
+
+def preprocess s
+  s.split.map { |i| T.new i }
+end
+
+def init input, n, active_chart, passive_chart, grammar
+  grammar.rules.select { |r| r.arity==0 }.each { |r|
+    input.each_index { |i|
+      if input[i, r.rhs.size].map{|x|x.word}==r.rhs.map{|x|x.word}
+        passive_chart.add Item.new(r), i, i+r.rhs.size, i+r.rhs.size, r.rhs.size
+        passive_chart.d["#{i},#{i+r.rhs.size},#{r.lhs.symbol}"] = true
+      end
+    }
+  }
+end
+
+def scan item, passive_chart, input
+  while item.rhs[item.dot].class == T
+    break if item.span.right > input.size-1
+    if item.rhs[item.dot].word == input[item.span.right].word
+      item.dot += 1
+      item.span.right += 1
+      break if item.dot == item.rhs.size
+    else
+      break
+    end
+  end
+end
+
+def parse input, n, active_chart, passive_chart, grammar
+  rules_starting_with_t = grammar.rules.select { |r| r.arity > 0 && r.rhs.first.class==T }
+  rules_starting_with_nt = grammar.rules.select { |r| r.rhs.first.class == NT }
+
+  # outer loop
+  2.upto(n) { |span|
+    0.upto(n-span) { |k|
+
+      # try to apply rules starting with T
+      rules_starting_with_t.select { |r| r.rhs.first.word == input[k].word }.each { |r|
+        new_item = Item.new r
+        new_item.span.left = k
+        new_item.span.right = k
+        new_item.dot = 0
+        scan new_item, passive_chart, input
+        active_chart.at(k, k+span) << new_item if new_item.span.right < k+span
+      }
+
+      # seed active chart
+      rules_starting_with_nt.each { |r|
+        # no eps-productions!
+        next if r.rhs.size > span
+        #puts "#{r.rhs.size} #{span}"
+        new_item = Item.new r
+        new_item.span.left = k
+        new_item.span.right = k
+        new_item.dot = 0
+        active_chart.at(k, k+span) << new_item
+      }
+
+      puts "#{k} #{k+span}"
+
+      # inner loop
+      puts "SIZE #{active_chart.at(k,k+span).size}"
+      while !active_chart.at(k,k+span).empty?
+      active_item = active_chart.at(k, k+span).pop
+
+      1.upto(span-1) { |span2|
+        k.upto((k+span)-span2) { |l|
+
+        #puts "passive chart sz #{passive_chart.at(l, l+span2).size} #{l},#{l+span2}"
+        #passive_chart.at(l, l+span2).select { |item| item.lhs.symbol==active_item.rhs[active_item.dot].symbol }.each { |passive_item|
+        #  if l==0&&span2==2
+        #    puts "   #{passive_item}"
+        #  end
+        if passive_chart.d["#{l},#{l+span2},#{active_item.rhs[active_item.dot].symbol}"]
+          if l == active_item.span.right
+              new_item = Item.new active_item
+              new_item.span.left = active_item.span.left
+              new_item.span.right = l+span2
+              new_item.dot += 1
+              scan new_item, passive_chart, input
+              if new_item.dot == new_item.rhs.size
+                if new_item.span.left==k&&new_item.span.right==(k+span)
+                  #puts "NP@#{k},#{k+span} #{new_item}"
+                  passive_chart.at(k,k+span) << new_item
+                end
+              else
+                if new_item.rhs[new_item.dot].class==NT && new_item.span.right < (k+span)
+                  #puts "NA@#{k},#{k+span} #{new_item}"
+                  active_chart.at(k,k+span) << new_item
+                end
+              end
+          end
+        #}
+        end
+
+#          # try to advance items
+#          passive_chart.at(l, l+span2).each { |passive_item|
+#            active_chart.at(k, k+span).select { |active_item| active_item.rhs[active_item.dot].symbol == passive_item.lhs.symbol }.each { |active_item|
+#              if passive_item.span.left == active_item.span.right
+#                new_item = Item.new active_item
+#                new_item.span.left = active_item.span.left
+#                new_item.span.right = passive_item.span.right
+#                new_item.dot += 1
+#                scan new_item, passive_chart, input
+#                if new_item.dot == new_item.rhs.size
+#                  if new_item.span.left==k&&new_item.span.right==(k+span)
+#                    puts "NP@#{k},#{k+span} #{new_item}"
+#                    passive_chart.at(k,k+span) << new_item
+#                  end
+#                else
+#                  # item is dead unless it has an NT to fill
+#                  if new_item.rhs[new_item.dot].class==NT && new_item.span.right < (k+span)
+#                    puts "NA@#{k},#{k+span} #{new_item}"
+#                    active_chart.at(k,k+span) << new_item
+#                  end
+#                end
+#              end
+#            }
+#          }
+#
+
+        }
+      }
+
+      end
+
+    }
+  }
+end
+
+def main
+  #input = preprocess 'ich sah ein kleines haus'
+  #input = preprocess 'lebensmittel schuld an europäischer inflation'
+  input = preprocess 'offizielle prognosen sind von nur 3 prozent ausgegangen , meldete bloomberg .'
+  n = input.size
+  g = Grammar.new 'example/grammar.3.gz'
+  #g.add_glue_rules
+  passive_chart = Chart.new n
+  active_chart = Chart.new n
+  init input, n, active_chart, passive_chart, g
+  parse input, n, active_chart, passive_chart, g
+  #puts "---\npassive chart"
+  #visit(n, n, 0) { |i,j| puts "#{i},#{j}"; passive_chart.at(i,j).each { |item| puts ' '+item.to_s if item.span.left==i&&item.span.right==j }; puts }
+  #puts "\nactive chart"
+  #visit(n, n, 0) { |i,j| puts "#{i},#{j}"; active_chart.at(i,j).each { |item| puts ' '+item.to_s }; puts }
+
+end
+
+
+main
+
diff --git a/intersect2.rb b/intersect2.rb
new file mode 100644
index 0000000..0d82c1d
--- /dev/null
+++ b/intersect2.rb
@@ -0,0 +1,176 @@
+#!/usr/bin/env ruby
+
+require_relative './grammar.rb'
+STDOUT.sync = true
+
+
+class Chart
+
+  def initialize n
+    @m = []
+    (n+1).times {
+      _ = []
+      (n+1).times { _ << [] }
+      @m << _
+    }
+    @b = {}
+  end
+
+  def at i, j
+    @m[i][j]
+  end
+
+  def add i, j, item
+    at(i,j) << item
+    @b["#{i},#{j},#{item.lhs.symbol}"] = true
+  end
+
+  def has symbol, i, j
+    return @b["#{i},#{j},#{symbol}"]
+  end
+end
+
+class Span
+  attr_accessor :left, :right
+
+  def initialize left=nil, right=nil
+    @left = left
+    @right = right
+  end
+end
+
+class Item < Rule
+  attr_accessor :lhs, :rhs, :span, :dot
+
+  def initialize rule_or_item, left, right, dot
+    @lhs = rule_or_item.lhs
+    @rhs = rule_or_item.rhs.dup
+    @span = Span.new left, right
+    @dot = dot
+  end
+
+  def to_s
+    "#{lhs} -> #{rhs.map{|i|i.to_s}.insert(@dot,'*').join ' '} [dot@#{@dot}] [arity=#{arity}] (#{@span.left}, #{@span.right})"
+  end
+end
+
+def init input, n, active_chart, passive_chart, grammar
+  grammar.flat.each { |r|
+    input.each_index { |i|
+      if input[i, r.rhs.size] == r.rhs.map { |x| x.word }
+        new_item = Item.new r, i, i+r.rhs.size, r.rhs.size
+        passive_chart.add i, i+r.rhs.size, new_item
+      end
+    }
+  }
+end
+
+def scan item, input, limit, passive_chart
+  while item.rhs[item.dot].class == T && item.span.right < limit
+    if item.rhs[item.dot].word == input[item.span.right]
+      item.dot += 1
+      item.span.right += 1
+    else
+      break
+    end
+  end
+end
+
+def parse input, n, active_chart, passive_chart, grammar
+  2.upto(n) { |span| # outer loop
+    0.upto(n-span) { |k|
+
+      puts " span(#{k},#{k+span})"
+
+      # try to apply rules starting with T
+      grammar.mixed.select { |r| r.rhs.first.word == input[k] }.each { |r|
+        new_item = Item.new r, k, k, 0
+        scan new_item, input, k+span, passive_chart
+        active_chart.at(k,k+span) << new_item
+      }
+
+      # seed active chart
+      grammar.rewrite.each { |r|
+        next if r.rhs.size > span
+        active_chart.at(k,k+span) << Item.new(r, k, k, 0)
+      }
+
+      active_chart.at(k,k+span).each { |active_item|
+        next if active_item.rhs[active_item.dot].class==T
+        # inner loop
+        1.upto(span-1) { |span2|
+          k.upto((k+span)-span2) { |l|
+
+            if passive_chart.has active_item.rhs[active_item.dot].symbol, l, l+span2
+              if l == active_item.span.right
+                new_item = Item.new active_item, active_item.span.left, l+span2, active_item.dot+1
+                scan new_item, input, k+span, passive_chart
+                if new_item.dot == new_item.rhs.size # done with item
+                  if new_item.span.left == k && new_item.span.right == k+span
+                    passive_chart.add k, k+span, new_item
+                  end
+                else
+                  if new_item.rhs[new_item.dot].class == NT && new_item.span.right+(new_item.rhs.size-(new_item.dot)) <= k+span
+                    active_chart.at(k,k+span) << new_item
+                  end
+                end
+              end
+            end
+          }
+        }
+      }
+
+      # 'self-filling' step
+      passive_chart.at(k,k+span).each { |passive_item|
+        active_chart.at(k,k+span).each { |active_item|
+          next if active_item.rhs[active_item.dot].class!=NT
+          if passive_item.lhs.symbol == active_item.rhs[active_item.dot].symbol
+            next if not active_item.span.right==passive_item.span.left
+            new_item = Item.new active_item, active_item.span.left, passive_item.span.right, active_item.dot+1
+            scan new_item, input, k+span, passive_chart
+            if new_item.dot == new_item.rhs.size
+              if new_item.span.left == k && new_item.span.right == k+span
+                passive_chart.add k, k+span, new_item
+              else
+                puts "#{new_item}" # FIXME never happens
+              end
+            else
+              if new_item.rhs[new_item.dot].class == NT && new_item.span.right+(new_item.rhs.size-(new_item.dot)) <= k+span
+                puts "NA@#{k},#{k+span} #{new_item}"
+                active_chart.at(k,k+span) << new_item
+              end
+            end
+          end
+        }
+      }
+    }
+  }
+end
+
+def visit n, depth, skip=0 # FIXME
+  (depth-skip).times { |i|
+    i += skip
+    0.upto(n-(i+1)) { |j|
+      yield j, j+i+1
+    }
+  }
+end
+
+def main
+  #input = 'ich sah ein kleines haus'.split
+  input = 'lebensmittel schuld an europäischer inflation'.split
+  #input = 'offizielle prognosen sind von nur 3 prozent ausgegangen , meldete bloomberg .'.split
+  n = input.size
+  grammar = Grammar.new 'example/grammar.x'
+  grammar.add_glue_rules
+  passive_chart = Chart.new n
+  active_chart = Chart.new n
+  init input, n, active_chart, passive_chart, grammar
+  parse input, n, active_chart, passive_chart, grammar
+  puts "---\npassive chart"
+  visit(n, n, 0) { |i,j| puts "#{i},#{j}"; passive_chart.at(i,j).each { |item| puts ' '+item.to_s }; puts }
+end
+
+
+main
+
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