17 files changed, 729 insertions, 0 deletions
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..1d9c4a0
--- /dev/null
+++ b/README.md
@@ -0,0 +1,10 @@
+dags.rb
+fileutil.rb
+PriorityQueue.rb
+semirings.rb
+SparseVector.rb
+stringutil.rb
+tfidf.rb
+ttable.rb
+Vector.rb
+
diff --git a/lib/nlp_ruby.rb b/lib/nlp_ruby.rb
new file mode 100755
index 0000000..4981bb0
--- /dev/null
+++ b/lib/nlp_ruby.rb
@@ -0,0 +1,16 @@
+#!/usr/bin/env ruby
+
+require 'rubynlp/stringutil'
+require 'rubynlp/fileutil'
+require 'rubynlp/Vector'
+require 'rubynlp/SparseVector'
+require 'rubynlp/PriorityQueue'
+require 'rubynlp/tfidf'
+require 'rubynlp/ttable'
+require 'rubynlp/dags'
+require 'rubynlp/semirings'
+
+STDIN.set_encoding 'utf-8'
+STDOUT.set_encoding 'utf-8'
+STDERR.set_encoding 'utf-8'
+
diff --git a/lib/nlp_ruby/PriorityQueue.rb b/lib/nlp_ruby/PriorityQueue.rb
new file mode 100644
index 0000000..22662b3
--- /dev/null
+++ b/lib/nlp_ruby/PriorityQueue.rb
@@ -0,0 +1,36 @@
+# FIXME dags
+# this assumes that elements in the queue
+# have a numerical member named 'score'
+class PriorityQueue
+
+  def initialize a=Array.new
+    @queue = Array.new a
+  end
+
+  def sort!
+    @queue.sort_by! { |i| -i.score }
+  end
+
+  def pop
+    sort!
+    @queue.pop
+  end
+
+  def push i
+    @queue << i
+  end
+
+  def empty?
+    @queue.empty?
+  end
+
+  # FIXME
+  def to_s
+    a = []
+    @queue.each { |i|
+      a << "#{i.to_s}[#{i.score}]"
+    }
+    "[#{a.join ', '}]"
+  end
+end
+
diff --git a/lib/nlp_ruby/SparseVector.rb b/lib/nlp_ruby/SparseVector.rb
new file mode 100644
index 0000000..0033690
--- /dev/null
+++ b/lib/nlp_ruby/SparseVector.rb
@@ -0,0 +1,64 @@
+class SparseVector < Hash
+
+  def initialize
+    super
+    self.default = 0
+  end
+
+  def from_hash h
+    h.each_pair { |k,v| self[k] = v }
+  end
+
+  def sum
+    self.values.inject(:+)
+  end
+
+  def average
+    self.sum/self.size.to_f
+  end
+
+  def variance
+    avg = self.average
+    var = 0.0
+    self.values.each { |i| var += (avg - i)**2 }
+    return var
+  end
+
+  def stddev
+    Math.sqrt self.variance
+  end
+
+  def dot other
+    sum = 0.0
+    self.each_pair { |k,v| sum += v * other[k] }
+    return sum
+  end
+
+  def magnitude
+    Math.sqrt self.values.inject { |sum,i| sum+i**2 }
+  end
+
+  def cosinus_sim other
+    self.dot(other)/(self.magnitude*other.magnitude)
+  end
+
+  def euclidian_dist other
+    dims = [self.keys, other.keys].flatten.uniq
+    sum = 0.0
+    dims.each { |d| sum += (self[d] - other[d])**2 }
+    return Math.sqrt(sum)
+  end
+end
+
+def mean_sparse_vector array_of_vectors
+  mean = SparseVector.new
+  array_of_vectors.each { |i|
+    i.each_pair { |k,v|
+      mean[k] += v
+    }
+  }
+  n = array_of_vectors.size.to_f
+  mean.each_pair { |k,v| mean[k] = v/n }
+  return mean
+end
+
diff --git a/lib/nlp_ruby/Vector.rb b/lib/nlp_ruby/Vector.rb
new file mode 100644
index 0000000..c749ed9
--- /dev/null
+++ b/lib/nlp_ruby/Vector.rb
@@ -0,0 +1,43 @@
+class Vector < Array
+
+  def sum
+    self.inject(:+)
+  end
+
+  def average
+    self.sum/self.size.to_f
+  end
+
+  def variance
+    avg = self.average
+    var = 0.0
+    self.each { |i| var += (avg - i)**2 }
+    var
+  end
+
+  def stddev list_of_values, decimal_places=-1
+    Math.sqrt self.variance
+  end
+
+  def dot other
+    return nil if self.size!=other.size
+    sum = 0.0
+    self.each_with_index { |i,j| sum += i*other[j] }
+    return sum
+  end
+
+  def magnitude
+     Math.sqrt self.inject { |sum,i| sum+i**2 }
+  end
+
+  def cosinus_sim other
+    return self.dot(other)/(self.mag*other.mag)
+  end
+
+  def euclidian_dist other
+    sum = 0.0
+    self.each_with_index { |i,j| sum += (i - other[j])**2 }
+    return Math.sqrt(sum)
+  end
+end
+
diff --git a/lib/nlp_ruby/dags.rb b/lib/nlp_ruby/dags.rb
new file mode 100644
index 0000000..7767be1
--- /dev/null
+++ b/lib/nlp_ruby/dags.rb
@@ -0,0 +1,218 @@
+###########################
+# TODO
+# output paths
+# visualization?
+# algorithms:
+#  beam search
+#  best-first
+#  kbest
+#  kruskal (MST)?
+#  transitive closure?
+###########################
+
+require 'json'
+
+
+module DAG
+
+
+class DAG::Node
+  attr_accessor :label, :edges, :incoming, :score, :mark
+
+  def initialize label=nil, edges=[], incoming=[], score=nil
+    @label    = label
+    @edges    = edges # outgoing
+    @incoming = incoming
+    @score    = nil
+  end
+
+  def add_edge head, weight=0
+    exit if self==head # no self-cycles!
+    @edges << DAG::Edge.new(self, head, weight)
+    return @edges.last
+  end
+
+  def to_s
+    "DAG::Node<label:#{label}, edges:#{edges.size}, incoming:#{incoming.size}>"
+  end
+
+  def repr
+    "#{to_s} #{@score} out:#{@edges} in:[#{@incoming.map{|e| e.to_s}.join ', '}]"
+  end
+end
+
+class DAG::Edge
+  attr_accessor :tail, :head, :weight, :mark
+
+  def initialize tail=nil, head=nil, weight=0
+    @tail   = tail
+    @head   = head
+    @weight = weight
+    @mark   = false # did we already follow this edge? -- for topological sorting
+  end
+
+  def to_s
+    s = "DAG::Edge<#{@tail} ->[#{weight}] #{@head}"
+    s += " x" if @mark
+    s += ">"
+    s
+  end
+end
+
+# depth-first search
+#  w/o markings as we do not have cycles
+def DAG::dfs n, target_label
+  return n if n.label==target_label # assumes uniq labels!
+  stack = n.edges.map { |i| i.head }
+  while !stack.empty?
+    m = stack.pop
+    return DAG::dfs m, target_label
+  end
+  return nil
+end
+
+# breadth-first search
+#  w/o markings as we do not have cycles
+def DAG::bfs n, target_label
+  queue = [n]
+  while !queue.empty?
+    m = queue.shift
+    return m if m.label==target_label
+    m.edges.each { |e| queue << e.head }
+  end
+  return nil
+end
+
+# topological sort
+def DAG::topological_sort graph
+  sorted = []
+  s = graph.reject { |n| !n.incoming.empty? }
+  while !s.empty?
+    sorted << s.shift
+    sorted.last.edges.each { |e|
+      e.mark = true
+      s << e.head if e.head.incoming.reject{|f| f.mark}.empty?
+    }
+  end
+  return sorted
+end
+
+# initialize graph scores with semiring One
+def DAG::init graph, semiring, source_node
+  graph.each {|n| n.score=semiring.null}
+  source_node.score = semiring.one
+end
+
+# viterbi
+def DAG::viterbi graph, semiring=ViterbiSemiring, source_node
+  toposorted = DAG::topological_sort(graph)
+  DAG::init(graph, semiring, source_node)
+  toposorted.each { |n|
+    n.incoming.each { |e|
+      # update
+      n.score = \
+        semiring.add.call(n.score, \
+                          semiring.multiply.call(e.tail.score, e.weight)
+        )
+    }
+  }
+end
+
+# forward viterbi
+def DAG::viterbi_forward graph, semiring=ViterbiSemiring, source_node
+  toposorted = DAG::topological_sort(graph)
+  DAG::init(graph, semiring, source_node)
+  toposorted.each { |n|
+    n.edges.each { |e|
+      e.head.score = \
+        semiring.add.call(e.head.score, \
+                          semiring.multiply.call(n.score, e.weight)
+        )
+    }
+  }
+end
+
+# Dijkstra algorithm
+#  for A*-search we would need an optimistic estimate of
+#  future cost at each node
+def DAG::dijkstra graph, semiring=RealSemiring.new, source_node
+  DAG::init(graph, semiring, source_node)
+  q = PriorityQueue.new graph
+  while !q.empty?
+    n = q.pop
+    n.edges.each { |e|
+      e.head.score = \
+        semiring.add.call(e.head.score, \
+                          semiring.multiply.call(n.score, e.weight))
+      q.sort!
+    }
+  end
+end
+
+# Bellman-Ford algorithm
+def DAG::bellman_ford(graph, semiring=RealSemiring.new, source_node)
+  DAG::init(graph, semiring, source_node)
+  edges = []
+  graph.each { |n| edges |= n.edges }
+  # relax edges
+  (graph.size-1).times{ |i|
+    edges.each { |e|
+      e.head.score = \
+        semiring.add.call(e.head.score, \
+                          semiring.multiply.call(e.tail.score, e.weight))
+    }
+  }
+  # we do not allow cycles (negative or positive)
+end
+
+# Floyd algorithm
+def DAG::floyd(graph, semiring=nil)
+  dist_matrix = []
+  graph.each_index { |i|
+    dist_matrix << []
+    graph.each_index { |j|
+      val = 1.0/0.0
+      val = 0.0 if i==j
+      dist_matrix.last << val
+    }
+  }
+  edges = []
+  graph.each { |n| edges |= n.edges }
+  edges.each { |e|
+    dist_matrix[graph.index(e.tail)][graph.index(e.head)] = e.weight
+  }
+  0.upto(graph.size-1) { |k|
+    0.upto(graph.size-1) { |i|
+      0.upto(graph.size-1) { |j|
+        if dist_matrix[i][k] + dist_matrix[k][j] < dist_matrix[i][j]
+          dist_matrix  [i][j] = dist_matrix[i][k] + dist_matrix[k][j]
+        end
+      }
+    }
+  }
+  return dist_matrix
+end
+
+
+# returns a list of nodes (graph) and a hash for finding
+# nodes by their label (these need to be unique!)
+def DAG::read_graph_from_json fn, semiring=RealSemiring.new
+  graph = []
+  nodes_by_label = {}
+  h = JSON.parse File.new(fn).read
+  h['nodes'].each { |i|
+    n = DAG::Node.new i['label']
+    graph << n
+    nodes_by_label[n.label] = n
+  }
+  h['edges'].each { |i|
+    n = nodes_by_label[i['tail']]
+    a = n.add_edge(nodes_by_label[i['head']], semiring.convert.call(i['weight'].to_f))
+    nodes_by_label[i['head']].incoming << a
+  }
+  return graph, nodes_by_label
+end
+
+
+end # module
+
diff --git a/lib/nlp_ruby/fileutil.rb b/lib/nlp_ruby/fileutil.rb
new file mode 100644
index 0000000..825ceb4
--- /dev/null
+++ b/lib/nlp_ruby/fileutil.rb
@@ -0,0 +1,61 @@
+require 'zlib'
+
+
+class ReadFile
+
+  def initialize fn, encoding='utf-8'
+    if fn.split('.').last == 'gz'
+      @f = Zlib::GzipReader.new(File.new(fn, 'rb'), :external_encoding=>encoding)
+    elsif fn == '-'
+      @f = STDIN
+      STDIN.set_encoding encoding
+    else
+      @f = File.new fn, 'r'
+      @f.set_encoding encoding
+    end
+  end
+
+  def gets
+    @f.gets { |line| yield line }
+  end
+
+  def readlines
+    @f.readlines
+  end
+
+  def readlines_strip
+    self.readlines.map{ |i| i.strip }
+  end
+
+  def read
+    @f.read
+  end
+
+  def close
+    @f.close if @f!=STDIN
+  end
+end
+
+class WriteFile
+
+  def initialize fn, encoding='utf-8'
+    if fn.split('.').last == 'gz'
+      @f = Zlib::GzipWrite.new(File.new(fn, 'wb+'), :external_encoding=>encoding)
+    elsif fn == '-'
+      @f = STDOUT
+      STDOUT.set_encoding encoding
+    else
+      @f = File.new fn, 'w+'
+      @f.set_encoding encoding
+    end
+  end
+
+  def write s
+    @f.write s
+  end
+
+  def close
+    @f.close if @f!=STDIN
+  end
+end
+
diff --git a/lib/nlp_ruby/semirings.rb b/lib/nlp_ruby/semirings.rb
new file mode 100644
index 0000000..a06f151
--- /dev/null
+++ b/lib/nlp_ruby/semirings.rb
@@ -0,0 +1,68 @@
+# semirings for graphs as described in
+# 'Dynamic Programming Algorithms in
+#  Semiring and Hypergraph Frameworks' (Liang Huang)
+class Semiring
+  attr_accessor :add, :multiply, :one, :null, :convert
+end
+
+class BooleanSemiring < Semiring
+  def initialize
+    @add = Proc.new { |a,b| a||b }
+    @multiply =  Proc.new { |a,b| a&&b }
+    @one = true
+    @null = false
+    @convert = Proc.new { |v| true && v!=0 }
+  end
+end
+
+class ViterbiSemiring < Semiring
+  def initialize
+    @add = Proc.new { |a,b| [a,b].max }
+    @multiply =  Proc.new { |a,b| a*b }
+    @one = 1.0
+    @null = 0.0
+    @convert = Proc.new { |v| v }
+  end
+end
+
+class InsideSemiring < Semiring
+  def initialize
+    @add = Proc.new { |a,b| a+b }
+    @multiply =  Proc.new { |a,b| a*b }
+    @one = 1.0
+    @null = 0.0
+    @convert = Proc.new { |v| v }
+  end
+end
+
+class RealSemiring < Semiring
+  def initialize
+    @add = Proc.new { |a,b| [a,b].min }
+    @multiply =  Proc.new { |a,b| a+b }
+    @one = 0.0
+    @null = 1.0/0.0
+    @convert = Proc.new { |v| v }
+  end
+end
+
+# for longest/worst paths
+class RealxSemiring < Semiring
+  def initialize
+    @add = Proc.new { |a,b| [a,b].max }
+    @multiply =  Proc.new { |a,b| a+b }
+    @one = -1.0/0.0
+    @null = 0.0
+    @convert = Proc.new { |v| v }
+  end
+end
+
+class CountingSemiring < Semiring
+  def initialize
+    @add = Proc.new { |a,b| a+b }
+    @multiply =  Proc.new { |a,b| a*b }
+    @one = 1.0
+    @null = 0.0
+    @convert = Proc.new { |v| if v!=0 then 1 else 0 end }
+  end
+end
+
diff --git a/lib/nlp_ruby/stringutil.rb b/lib/nlp_ruby/stringutil.rb
new file mode 100644
index 0000000..e9a3bc9
--- /dev/null
+++ b/lib/nlp_ruby/stringutil.rb
@@ -0,0 +1,34 @@
+# whitespace 'tokenizer'
+def tokenize s
+  s.strip.split
+end
+
+def splitpipe s
+  s.strip.split(/\s*\|\|\|\s*/)
+end
+
+def downcase? s
+  s[/[[:lower:]]/]
+end
+
+# iterator over n-grams
+def ngrams(s, n, fix=false)
+  a = tokenize s
+  a.each_with_index { |tok, i|
+    tok.strip!
+    0.upto([n-1, a.size-i-1].min) { |m|
+      yield a[i..i+m] if !fix||(fix&&a[i..i+m].size==n)
+    }
+  }
+end
+
+# a=1.0 b=2.0 => { 'a' => 1.0, 'b' => 2.0 }
+def read_feature_string s
+  map = SparseVector.new
+  tokenize(s).each { |i|
+    key, value = i.split '='
+    map[key] = value.to_f
+  }
+  return map
+end
+
diff --git a/lib/nlp_ruby/tfidf.rb b/lib/nlp_ruby/tfidf.rb
new file mode 100644
index 0000000..84d55a5
--- /dev/null
+++ b/lib/nlp_ruby/tfidf.rb
@@ -0,0 +1,32 @@
+# returns key='raw frequency' for an
+# array-like object
+def tf array, stopwords=[]
+  v = {}; v.default = 0
+  array.uniq.each { |i|
+   next if stopwords.include? i
+   v[i] = array.count(i).to_f
+  }
+  return v
+end
+
+# smoothes raw frequencies of tf() in-place
+# a is a smoothing term
+def ntf hash, a=0.4
+  max = hash.values.max.to_f
+  hash.each_pair { |k,v|
+    hash[k] = a + (1-a)*(v/max)
+  }
+end
+
+# returns idf value for each word in a vocabulary
+def idf list_of_hashes
+  vocab = list_of_hashes.values.flatten.uniq
+  n = list_of_hashes.size.to_f
+  idf = {}
+  vocab.each { |i|
+    df = list_of_hashes.values.flatten.count i
+    idf[i] = Math.log(n/df)
+  }
+  return idf
+end
+
diff --git a/lib/nlp_ruby/ttable.rb b/lib/nlp_ruby/ttable.rb
new file mode 100644
index 0000000..20b1412
--- /dev/null
+++ b/lib/nlp_ruby/ttable.rb
@@ -0,0 +1,17 @@
+# table['some French string'] = [Array of English strings]
+def read_phrase_table fn
+  table = {}
+  f = ReadFile.new fn
+  while raw_rule = f.gets
+    french, english, features = splitpipe(raw_rule)
+    feature_map = read_feature_string(features)
+    if table.has_key? french
+      table[french] << [english, feature_map ]
+    else
+      table[french] = [[english, feature_map]]
+    end
+  end
+  f.close
+  return table
+end
+
diff --git a/lib/rubynlp.rb b/lib/rubynlp.rb
deleted file mode 100644
index e69de29..0000000
--- a/lib/rubynlp.rb
+++ /dev/null
diff --git a/nlp_ruby.gemspec b/nlp_ruby.gemspec
new file mode 100644
index 0000000..0737994
--- /dev/null
+++ b/nlp_ruby.gemspec
@@ -0,0 +1,13 @@
+Gem::Specification.new do |s|
+  s.name        = 'nlp_ruby'
+  s.version     = '0.1'
+  s.date        = '2014-01-29'
+  s.summary     = "nlp_ruby"
+  s.description = "NLP related tools and classes"
+  s.authors     = ["Patrick Simianer"]
+  s.email       = 'p@simianer.de'
+  s.files       = Dir['lib/*.rb', 'lib/nlp_ruby/*.rb']
+  s.homepage    = 'http://simianer.de'
+  s.license     = 'MIT'
+end
+
diff --git a/rubynlp.gemspec b/rubynlp.gemspec
deleted file mode 100644
index e69de29..0000000
--- a/rubynlp.gemspec
+++ /dev/null
diff --git a/test/dags.rb b/test/dags.rb
new file mode 100755
index 0000000..0e90d1b
--- /dev/null
+++ b/test/dags.rb
@@ -0,0 +1,47 @@
+#!/usr/bin/env ruby
+
+require 'nlp_ruby'
+require 'test/unit'
+
+
+class TestDAG <  Test::Unit::TestCase
+
+  def test_viterbi
+    semiring = ViterbiSemiring.new
+    graph, nodes_by_label = DAG::read_graph_from_json('dags/example.json', semiring)
+    DAG::viterbi(graph, semiring, nodes_by_label['0'])
+    assert_equal(nodes_by_label['100'].score, 0.003)
+  end
+
+  # no negative weights here!
+  def test_dijkstra
+    semiring = RealSemiring.new
+    graph, nodes_by_label = DAG::read_graph_from_json('dags/example.json', semiring)
+    DAG::dijkstra(graph, semiring, nodes_by_label['0'])
+    assert_equal(nodes_by_label['100'].score, 0.5)
+  end
+
+  def test_bellman_ford
+    semiring = RealSemiring.new
+    graph, nodes_by_label = DAG::read_graph_from_json('dags/example.json', semiring)
+    DAG::bellman_ford(graph, semiring, nodes_by_label['0'])
+    assert_equal(nodes_by_label['100'].score, 0.5)
+  end
+
+  def test_floyd
+    graph, nodes_by_label = DAG::read_graph_from_json('dags/example.json')
+    d = DAG::floyd(graph)
+    assert_equal(d[0][graph.size-1], 0.5)
+  end
+
+  def test_dfs
+    graph, nodes_by_label = DAG::read_graph_from_json('dags/example.json')
+    assert_equal(nodes_by_label['100'], DAG::dfs(nodes_by_label['0'], '100'))
+  end
+
+  def test_bfs
+    graph, nodes_by_label = DAG::read_graph_from_json('dags/example.json')
+    assert_equal(nodes_by_label['100'], DAG::bfs(nodes_by_label['0'], '100'))
+  end
+end
+
diff --git a/test/dags/example.json b/test/dags/example.json
new file mode 100644
index 0000000..3763359
--- /dev/null
+++ b/test/dags/example.json
@@ -0,0 +1,45 @@
+{
+
+"nodes":
+[
+ {"label":"0"},
+ {"label":"7"},
+ {"label":"5"},
+ {"label":"3"},
+ {"label":"11"},
+ {"label":"8"},
+ {"label":"2"},
+ {"label":"9"},
+ {"label":"10"},
+ {"label":"100"}
+],
+
+"edges":
+[
+ { "tail":"0", "head":"7", "weight":"0.1" },
+ { "tail":"0", "head":"5", "weight":"0.1" },
+ { "tail":"0", "head":"3", "weight":"0.3" },
+
+ { "tail":"7", "head":"11", "weight":"0.5" },
+ { "tail":"7", "head":"8",  "weight":"0.3" },
+
+ { "tail":"5", "head":"11", "weight":"0.5" },
+
+ { "tail":"3", "head":"8",  "weight":"0.1" },
+ { "tail":"3", "head":"10", "weight":"0.1" },
+
+ { "tail":"11", "head":"2",  "weight":"0.2" },
+ { "tail":"11", "head":"9",  "weight":"0.2" },
+ { "tail":"11", "head":"10", "weight":"0.3" },
+
+ { "tail":"8", "head":"9", "weight":"0.3" },
+
+ { "tail":"2", "head":"100", "weight":"0.1" },
+
+ { "tail":"9", "head":"100", "weight":"0.1" },
+
+ { "tail":"10", "head":"100", "weight":"0.1" }
+]
+
+}
+
diff --git a/test/dags/simple.json b/test/dags/simple.json
new file mode 100644
index 0000000..16a2ef0
--- /dev/null
+++ b/test/dags/simple.json
@@ -0,0 +1,25 @@
+{
+
+"nodes":
+[
+ {"label":"0"},
+ {"label":"7"},
+ {"label":"5"},
+ {"label":"6"},
+ {"label":"100"}
+],
+
+"arcs":
+[
+ { "tail":"0", "head":"7", "weight":"0.1" },
+ { "tail":"0", "head":"5", "weight":"0.1" },
+
+ { "tail":"7", "head":"100", "weight":"0.9" },
+
+ { "tail":"5", "head":"6", "weight":"0.3" },
+
+ { "tail":"6", "head":"100", "weight":"0.3" }
+]
+
+}
+