Fixed #19 by adding previously missing reshape.

The comment did say that only flat shapes were supported though.

tensorflow-ops/src/TensorFlow/EmbeddingOps.hs

@@ -25,7 +25,7 @@ import Control.Monad (zipWithM)
 import Data.Int (Int32, Int64)
 import Data.List (genericLength)
 import TensorFlow.Build (Build, colocateWith, render)
-import TensorFlow.Ops ()  -- Num instance for Tensor
+import TensorFlow.Ops (shape, scalar, vector)  -- Also Num instance for Tensor
 import TensorFlow.Tensor (Tensor, Value)
 import TensorFlow.Types (OneOf, TensorType)
 import qualified TensorFlow.GenOps.Core as CoreOps
@@ -56,24 +56,33 @@ embeddingLookup :: forall a b v .
                 -> Tensor Value b
                 -- ^ A `Tensor` with type `int32` or `int64`
                 -- containing the ids to be looked up in `params`.
-                -- The ids are required to be flat on entry and have
-                -- fewer than 2^31 entries.
+                -- The ids are required to have fewer than 2^31
+                -- entries.
                 -> Build (Tensor Value a)
                 -- ^ A dense tensor with shape `shape(ids) + shape(params)[1:]`.
-embeddingLookup params@(p1 : _) ids =
-        go (np :: Int32)
-  where 
-        go 1 = colocateWith p1 (render $ CoreOps.gather p1 ids)
-        go _ = CoreOps.dynamicStitch pindices <$> partitionedResult
-        np = genericLength params 
-        pAssignments = CoreOps.cast (ids `CoreOps.mod` np)
-        newIds = ids `CoreOps.div` np
-        originalIndices = CoreOps.range 0 (CoreOps.size ids) 1
-        -- Partition list of ids based on assignments into np separate lists
-        gatherIds = CoreOps.dynamicPartition np newIds pAssignments
-        -- Similarly, partition the original indices.
-        pindices = CoreOps.dynamicPartition np originalIndices pAssignments
-        -- Do np separate lookups, finding embeddings for plist[p] in params[p]
-        partitionedResult = zipWithM
-                            (\p g -> colocateWith p $ render $ CoreOps.gather p g)
-                            params gatherIds
+embeddingLookup [p0] ids = colocateWith p0 (render $ CoreOps.gather p0 ids)
+embeddingLookup params@(p0 : _) ids = do
+    -- Do np separate lookups, finding embeddings for plist[p] in params[p]
+    partitionedResult <- zipWithM
+                        (\p g -> colocateWith p $ render $ CoreOps.gather p g)
+                        params gatherIds
+    let unshapedResult = CoreOps.dynamicStitch pindices partitionedResult
+    -- Shape restoration is not as optimal as it would be with client
+    -- side shape tracking.
+    paramShape <- colocateWith p0 (render (shape p0))
+    let finalShape = CoreOps.concat 0 [shape ids, tailShape]
+        tailShape = CoreOps.slice paramShape (singleton 1) (singleton (-1))
+    render $ CoreOps.reshape unshapedResult finalShape
+  where
+    np = genericLength params
+    flatIds = CoreOps.reshape ids (singleton (-1))
+    pAssignments = CoreOps.cast (flatIds `CoreOps.mod` np)
+    newIds = flatIds `CoreOps.div` np
+    originalIndices = CoreOps.range 0 (CoreOps.size flatIds) 1
+    -- Partition list of ids based on assignments into np separate lists
+    gatherIds = CoreOps.dynamicPartition np newIds pAssignments
+    -- Similarly, partition the original indices.
+    pindices = CoreOps.dynamicPartition np originalIndices pAssignments
+    singleton i = vector [i :: Int32]
+
+embeddingLookup [] _ = error "embeddingLookup requires params to be non empty"