1 files changed, 40 insertions, 17 deletions
diff --git a/lib/nlp_ruby/SparseVector.rb b/lib/nlp_ruby/SparseVector.rb
index b80373c..3096412 100644
--- a/lib/nlp_ruby/SparseVector.rb
+++ b/lib/nlp_ruby/SparseVector.rb
@@ -12,14 +12,32 @@ class SparseVector < Hash
     a.each_with_index { |i,j| self[j] = i }
   end
 
+  def self.from_a a
+    v = SparseVector.new
+    v.from_a a
+    return v
+  end
+
   def from_h h
     h.each_pair { |k,v| self[k] = v }
   end
 
+  def self.from_h h
+    v = SparseVector.new
+    v.from_h h
+    return v
+  end
+
   def from_s s
     from_h eval(s)
   end
 
+  def self.from_s s
+    v = SparseVector.new
+    v.from_s s
+    return v
+  end
+
   def to_kv sep='=', join=' '
     a = []
     self.each_pair { |k,v|
@@ -35,6 +53,12 @@ class SparseVector < Hash
     }
   end
 
+  def self.from_kv s
+    v = SparseVector.new
+    v.from_kv s
+    return v
+  end
+
   def from_file fn, sep='='
     f = ReadFile.new(fn)
     while line = f.gets
@@ -44,6 +68,12 @@ class SparseVector < Hash
     end
   end
 
+  def self.from_file fn, sep='='
+    v = SparseVector.new
+    v.from_file fn, sep
+    return v
+  end
+
   def join_keys other
     self.keys + other.keys
   end
@@ -126,24 +156,17 @@ class SparseVector < Hash
     }
     return new
   end
-end
-
-
-module SparseVector
-
 
-def SparseVector::mean a
-  mean = SparseVector.new
-  a.each { |i|
-    i.each_pair { |k,v|
-      mean[k] += v
+  def self.mean a
+    mean = SparseVector.new
+    a.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
-
-
+    n = a.size.to_f
+    mean.each_pair { |k,v| mean[k] = v/n }
+    return mean
+  end
 end