intersect2 correct & fast (ok, at least not impossibly slow)

1 files changed, 221 insertions, 0 deletions

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
+