Change the meaning of WER

src/GEval/Core.hs

@@ -516,7 +516,21 @@ gevalCoreOnSources (Mean (MultiLabelFMeasure beta)) _
       intoWords (RawItemTarget t) = Prelude.map unpack $ Data.Text.words t
       intoWords (PartiallyParsedItemTarget ts) = Prelude.map unpack ts
 
-gevalCoreOnSources (Mean _) _ = error $ "Mean/ meta-metric defined only for MultiLabel-F1 for the time being"
+gevalCoreOnSources (Mean WER) _
+  = gevalCoreWithoutInputOnItemTargets (Right . intoWords)
+                                       (Right . getWords)
+                                       ((uncurry (/.)) . (uncurry werStep))
+                                       averageC
+                                       id
+                                       noGraph
+    where
+      -- repeated as below, as it will be refactored into dependent types soon anyway
+      getWords (RawItemTarget t) = Prelude.map unpack $ selectByStandardThreshold $ parseIntoProbList t
+      getWords (PartiallyParsedItemTarget ts) = Prelude.map unpack ts
+      intoWords (RawItemTarget t) = Prelude.map unpack $ Data.Text.words t
+      intoWords (PartiallyParsedItemTarget ts) = Prelude.map unpack ts
+
+gevalCoreOnSources (Mean _) _ = error $ "Mean/ meta-metric defined only for MultiLabel-F1 and WER for the time being"
 
 -- only MultiLabel-F1 handled for JSONs for the time being...
 gevalCoreOnSources (MultiLabelFMeasure beta) _ = gevalCoreWithoutInputOnItemTargets (Right . intoWords)
@@ -588,7 +602,15 @@ gevalCoreOnSources GLEU _ = gevalCoreWithoutInput (Right . Prelude.map Prelude.w
         gleuAgg = CC.foldl gleuFuse (0, 0)
         gleuFuse (a1, a2) (b1, b2) = (a1 + b1, a2 + b2)
 
-gevalCoreOnSources WER _ = gevalCoreWithoutInput (Right . Prelude.words . unpack) (Right . Prelude.words . unpack) (uncurry werStep) averageC id noGraph
+gevalCoreOnSources WER _ = gevalCoreWithoutInput (Right . Prelude.words . unpack)
+                                                 (Right . Prelude.words . unpack)
+                                                 (uncurry werStep)
+                                                 werAgg
+                                                 werFinal
+                                                 noGraph
+  where werAgg = CC.foldl werFuse (0, 0)
+        werFuse (a1, a2) (b1, b2) = (a1 + b1, a2 + b2)
+        werFinal (errors, ref) = errors /. ref
 
 gevalCoreOnSources Accuracy _ = gevalCoreWithoutInput (Right . strip) (Right . strip) hitOrMiss averageC id noGraph
                       where hitOrMiss (exp, got) =

src/GEval/WER.hs

@@ -5,8 +5,8 @@ module GEval.WER
 import Data.Array
 import GEval.Common
 
-werStep :: Eq a => [a] -> [a] -> Double
-werStep expected got = (fromIntegral $ distance expected got) `safeDoubleDiv` (fromIntegral $ length expected)
+werStep :: Eq a => [a] -> [a] -> (Int, Int)
+werStep expected got = (distance expected got, length expected)
 
 -- see https://stackoverflow.com/questions/6718787/levenshtein-distance-cost
 distance u v = memo ! (m, n)

test/wer-simple/wer-simple/config.txt

@@ -1 +1 @@
---metric WER
+--metric Mean/WER