factor in _cumulate should be float

castle · Dec 30, 2015 · d4cd28c · d4cd28c
1 parent b5bff32
commit d4cd28c
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Showing 2 changed files with 30 additions and 6 deletions.
diff --git a/lib/tdigest/tdigest.rb b/lib/tdigest/tdigest.rb
@@ -191,7 +191,6 @@ def self.from_json(array)
 
     private
 
-
     def _add_weight(nearest, x, n)
       unless x == nearest.mean
         nearest.mean += n * (x - nearest.mean) / (nearest.n + n)
@@ -206,11 +205,8 @@ def _add_weight(nearest, x, n)
     end
 
     def _cumulate(exact = false)
-      factor = @last_cumulate == 0 ? Float::INFINITY : (@n / @last_cumulate)
-      if @n == @last_cumulate ||
-        !exact && @cx && @cx > (factor)
-        return
-      end
+      factor = @last_cumulate == 0 ? Float::INFINITY : (@n.to_f / @last_cumulate)
+      return if @n == @last_cumulate || (!exact && @cx && @cx > (factor))
 
       cumn = 0
       @centroids.each do |_, c|

diff --git a/test/tdigest_test.rb b/test/tdigest_test.rb
@@ -78,4 +78,32 @@ def test_that_it_has_a_version_number
       end
     end
   end
+
+  describe '#push' do
+    it "calls _cumulate so won't crash because of uninitialized mean_cumn" do
+      td = TDigest::TDigest.new
+      td.push [125000000.0,
+       104166666.66666666,
+       135416666.66666666,
+       104166666.66666666,
+       104166666.66666666,
+       93750000.0,
+       125000000.0,
+       62500000.0,
+       114583333.33333333,
+       156250000.0,
+       124909090.90909092,
+       104090909.0909091,
+       135318181.81818184,
+       104090909.0909091,
+       104090909.0909091,
+       93681818.18181819,
+       124909090.90909092,
+       62454545.45454546,
+       114500000.00000001,
+       156136363.63636366,
+       123567567.56756756,
+       102972972.97297296]
+    end
+  end
 end