SparseVector: fixes

2 files changed, 11 insertions, 1 deletions

diff --git a/lib/zipf/SparseVector.rb b/lib/zipf/SparseVector.rb
index 976ecaf..456aeb2 100644
--- a/lib/zipf/SparseVector.rb
+++ b/lib/zipf/SparseVector.rb
@@ -7,6 +7,10 @@ class SparseVector < Hash
     self.default = 0
     if arg.is_a? Array
       from_a arg
+    elsif arg.is_a? Hash
+      from_h arg
+    elsif arg.is_a? String
+      from_s arg
     end
   end
 
@@ -212,7 +216,9 @@ class SparseVector < Hash
   end
 
   def unit
-    return SparseVector.new(self).unit!
+    v = SparseVector.new(self)
+    v.unit!
+    return v
   end
 end
 
diff --git a/test/test_sparsevector.rb b/test/test_sparsevector.rb
index a23a7d3..2263c73 100755
--- a/test/test_sparsevector.rb
+++ b/test/test_sparsevector.rb
@@ -10,9 +10,13 @@ class TestSparseVector <  Test::Unit::TestCase
     v[:a] = 1
     v[:b] = 2
     v[:c] = 3
+    w = SparseVector.new v
     assert_equal Math.sqrt(1**2+2**2+3**2), v.norm
     v.unit!
     assert_equal v.norm, 1.0
+    q = w.unit
+    assert_equal q.norm, 1.0
+    assert_equal w.norm, Math.sqrt(1**2+2**2+3**2)
   end
 end