From 81f6b20d1c41d8906900c57ab71ec08a007ea02c Mon Sep 17 00:00:00 2001
From: Patrick Simianer <p@simianer.de>
Date: Tue, 4 Aug 2015 15:57:31 +0200
Subject: voted perceptron

---
 rerank.rb           | 27 +++++++++-------
 voted_perceptron.rb | 93 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 voted_test.rb       | 50 ++++++++++++++++++++++++++++
 3 files changed, 159 insertions(+), 11 deletions(-)
 create mode 100755 voted_perceptron.rb
 create mode 100755 voted_test.rb

diff --git a/rerank.rb b/rerank.rb
index 9e2a708..095e20b 100755
--- a/rerank.rb
+++ b/rerank.rb
@@ -3,13 +3,13 @@
 require 'zipf'
 
 class KbestItem
-  attr_accessor :rank, :model, :gold, :f, :model_orig
+  attr_accessor :rank, :model, :rr, :gold, :f
   def initialize s
     a = s.split "\t"
     @rank = a[0].to_i
     @gold = a[1].to_f
     @model = a[2].to_f
-    @model_orig = @model
+    @rr    = -1.0
     @f = SparseVector.from_kv a[3], "=", " "
   end
 
@@ -18,27 +18,32 @@ class KbestItem
   end
 end
 
-`mkdir rrkb`
 w = SparseVector.from_kv ReadFile.new(ARGV[0]).read, "\t", "\n"
 
+def o kl
+  scores = []
+  scores << kl.first.gold
+  kl.sort! { |i,j| j.model <=> i.model }
+  scores << kl.first.gold
+  kl.sort! { |i,j| j.rr <=> i.rr }
+  scores << kl.first.gold
+
+  puts scores.join "\t"
+end
+
 STDERR.write "reranking..\n"
 cur = []
 k_sum = 0
 j = 0
 while line = STDIN.gets
   item = KbestItem.new line.strip
-  item.model = w.dot(item.f)
+  item.rr = w.dot(item.f)
   if item.rank == 0 && cur.size > 0
-    cur.sort! { |i,j| j.model <=> i.model }
-    f = WriteFile.new "rrkb/#{j}.gz"
-    f.write cur.map{|x| x.to_s}.join("\n")
-    f.close
-    puts "RERANKED\t#{cur.first.gold}"
+    o cur
     cur = []
     j += 1
   end
   cur << item
 end
-cur.sort! { |i,j| j.model <=> i.model }
-puts "RERANKED\t#{cur.first.gold}"
+o cur
 
diff --git a/voted_perceptron.rb b/voted_perceptron.rb
new file mode 100755
index 0000000..13211b1
--- /dev/null
+++ b/voted_perceptron.rb
@@ -0,0 +1,93 @@
+#!/usr/bin/env ruby
+
+require 'zipf'
+
+STDERR.write "reading training data...\n"
+train = []
+train_f = ReadFile.new ARGV[0]
+n = 0
+while i = train_f.gets
+  train << SparseVector.from_kv(i.strip, '=', ' ')
+  n += 1
+  STDERR.write "#{n}\n" if n%1000==0
+end
+STDERR.write " training set size = #{train.size}\n"
+
+prev_loss = Float::MAX # converged?
+T = 1000000            # max number of iterations
+t = 0
+w = SparseVector.new   # 0 vector
+c = 0
+ws = []
+cs = []
+no_change = 0
+save_freq = 1
+if ARGV[1]
+  save_freq = ARGV[1].to_i
+end
+
+while true
+
+  if t == T
+    STDERR.write "\nreached max. number of iterations!\n"
+    break
+  end
+
+  STDERR.write "\niteration #{t}\n"
+
+  train.shuffle!
+  loss = 0.0
+  errors = 0
+  j = 1
+
+  train.each { |x|
+    m = w.dot(x)
+    if m <= 0.0
+      loss += m.abs
+      errors += 1
+      ws << SparseVector.new(w)
+      cs << c
+      w += x
+      c = 0
+    else
+      c += 1
+    end
+    STDERR.write '.'  if j%10==0
+    STDERR.write "\n" if j%1000==0
+    j += 1
+  }
+
+  STDERR.write "errors = #{errors} (avg = #{(errors/train.size.to_f).round 2}), loss = #{loss.round 2} (avg = #{(loss/train.size).round 2}); #w:#{ws.size}, max c:#{cs.max} \n"
+
+  if (loss.abs-prev_loss.abs).abs <= 10**-4
+    no_change += 1
+  else
+    no_change = 0
+  end
+  if no_change == 3
+    STDERR.write "\nno change in loss since three iterations (difference < 10**-4)!\n"
+    break
+  end
+  prev_loss = loss
+
+  if t%save_freq == 0
+    STDERR.write "\nwriting model to model.#{t}.gz ...\n"
+    f = WriteFile.new "model.#{t}.gz"
+    ws.each_with_index { |v,j|
+      f.write "#{cs[j]}\t#{v.to_kv("=", " ")+"\n"}"
+    }
+    f.close
+    STDERR.write "done!\n"
+  end
+
+  t += 1
+end
+
+STDERR.write "\nwriting model to model.final.gz ...\n"
+f = WriteFile.new "model.final.gz"
+ws.each_with_index { |v,j|
+  f.write "#{cs[j]}\t#{v.to_kv("=", " ")+"\n"}"
+}
+f.close
+STDERR.write "done!\n"
+
diff --git a/voted_test.rb b/voted_test.rb
new file mode 100755
index 0000000..c131ec2
--- /dev/null
+++ b/voted_test.rb
@@ -0,0 +1,50 @@
+#!/usr/bin/env ruby
+
+require 'zipf'
+
+STDOUT.sync = true
+
+STDERR.write "reading test data...\n"
+test = []
+test_f = ReadFile.new ARGV[0]
+n = 0
+while i = test_f.gets
+  test << SparseVector.from_kv(i.strip, '=', ' ')
+  n += 1
+  STDERR.write "#{n}\n" if n%1000==0
+end
+STDERR.write " test set size = #{test.size}\n"
+
+errors = 0
+ws = []
+cs = []
+ReadFile.readlines_strip(ARGV[1]).each { |l|
+  c, s = l.split "\t"
+  cs << c.to_i
+  next if !s||s.strip==""
+  ws << SparseVector.from_kv(s, "=", " ")
+}
+
+def sign(x)
+  if x <= 0
+    return -1.0
+  else
+    return 1.0
+  end
+end
+
+test.each { |x|
+  m = 0
+  ws.each_with_index{ |w,j|
+    m += sign(w.dot(x))*cs[j]
+  }
+  if m <= 0.0
+    errors += 1
+    puts -1
+  else
+    puts 1
+  end
+}
+
+STDERR.write "accuracy = #{(test.size-errors)/test.size.to_f}\n"
+
-- 
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