implement softmax in LogLossHashed

src/GEval/LogLossHashed.hs

@@ -30,12 +30,22 @@ murmurSeedValue = 0
 parseDistribution :: Word32 -> Word32 -> T.Text -> Either String HashedDistribution
 parseDistribution nbOfBits seed distroSpec =
   -- distribution spec is either...
-  if T.any (== ':') distroSpec
+  normalizeDistribution <$> if T.any (== ':') distroSpec
                             -- a space-separated list of words with their log probs
                             then parseDistributionFromWordList nbOfBits seed distroSpec
                             -- a direct list of 2^nbOfBits log probs
                             else parseDistributionFromLogProbList nbOfBits distroSpec
 
+normalizeDistribution :: HashedDistribution -> HashedDistribution
+normalizeDistribution distro =
+  -- we do softmax (if needed)
+  if probSum > 1.0 || probSum < (1.0 - epsilon)
+  then normalized
+  else distro
+  where probSum = V.foldl' (\s l -> (s + exp l)) 0.0 distro
+        normalized = V.map (\v -> log ((exp v) / probSum)) distro
+        epsilon = 0.00000001
+
 type DistroMonad s = ReaderT (VM.MVector s Double) (ST s)
 
 data WordSpec = AnyWord | SpecificWord T.Text

test/Spec.hs

@@ -87,6 +87,8 @@ main = hspec $ do
   describe "LogLossHashed challenge" $ do
     it "simple example" $ do
       runGEvalTest "log-loss-hashed-simple" `shouldReturnAlmost` 2.398479083333333
+    it "example with unnormalized values" $ do
+      runGEvalTest "log-loss-hashed-not-normalized" `shouldReturnAlmost` 1.0468455186722887
   describe "reading options" $ do
     it "can get the metric" $ do
       extractMetric "bleu-complex" `shouldReturn` (Just BLEU)

test/log-loss-hashed-not-normalized/log-loss-hashed-not-normalized-solution/test-A/out.tsv

@@ -0,0 +1,2 @@
+tak:10 nie:8.9
+niebieski:0 żółty:1.5 czerwony:-0.5

test/log-loss-hashed-not-normalized/log-loss-hashed-not-normalized/config.txt

@@ -0,0 +1 @@
+--metric LogLossHashed8

test/log-loss-hashed-not-normalized/log-loss-hashed-not-normalized/test-A/expected.tsv

@@ -0,0 +1,2 @@
+tak
+niebieski