Added support for ExpandDims gradient. (tensorflow#224)

Author: rikvdkleij

tensorflow-ops/src/TensorFlow/Gradient.hs

@@ -691,8 +691,8 @@ opGrad "MaxPool" nodeDef [toT -> x] [dz] =
     padding = lookupAttr nodeDef "padding" :: ByteString
     dataFormat = lookupAttr nodeDef "data_format" :: ByteString
 
-opGrad "Reshape" _ [toT -> x, _] [dz] =
-    [Just $ reshape dz $ shape (x :: Tensor Build a), Nothing]
+opGrad "Reshape" _ [toT -> x, _] [dz] = [Just $ reshape dz $ shape (x :: Tensor Build a), Nothing]
+opGrad "ExpandDims" n xs@[toT -> _, _] dzs@[_] = opGrad "Reshape" n xs dzs
 
 opGrad "OneHot" _ _ _ = [Nothing, Nothing, Nothing, Nothing]
 opGrad "TruncatedNormal" _ _ _ = [Nothing]
@@ -810,6 +810,7 @@ numOutputs o =
         "DynamicPartition" ->
             fromIntegral (lookupAttr o "num_partitions" :: Int64)
         "Exp" -> 1
+        "ExpandDims" -> 1
         "Gather" -> 1
         "LabelClasses" -> 1
         "LabelWeights" -> 1

tensorflow-ops/tests/GradientTest.hs

@@ -43,6 +43,7 @@ import Proto.Tensorflow.Core.Framework.Graph_Fields (node)
 import Proto.Tensorflow.Core.Framework.NodeDef_Fields (op)
 
 import qualified Data.ByteString.Char8 as BS
+import TensorFlow.Session (SessionT)
 
 testGradientSimple :: Test
 testGradientSimple = testCase "testGradientSimple" $ do
@@ -290,6 +291,35 @@ testTanhGrad = testCase "testTanhGrad" $ do
         TF.gradients y [x] >>= TF.run
     V.fromList [1] @=? dx
 
+testExpandDims :: Test
+testExpandDims =
+  testCase "testExpandDims" $ do
+    ([dx], [s]) <-
+      TF.runSession $ do
+        (x :: TF.Tensor TF.Value Float) <- TF.render $ TF.zeros $ TF.Shape [1, 2, 3 :: Int64]
+        let y = TF.expandDims x $ TF.constant (TF.Shape [1]) [0 :: Int32]
+        calculateGradWithShape y x
+    V.fromList [1, 1, 1, 1, 1, 1] @=? dx
+    V.fromList [1, 2, 3] @=? s
+
+testReshape :: Test
+testReshape =
+  testCase "testReshape" $ do
+    ([dx], [s]) <-
+      TF.runSession $ do
+        (x :: TF.Tensor TF.Value Float) <- TF.render $ TF.zeros $ TF.Shape [2, 2 :: Int64]
+        let y = TF.reshape x $ TF.constant (TF.Shape [2]) [1, 4 :: Int32]
+        calculateGradWithShape y x
+    V.fromList [1, 1, 1, 1] @=? dx
+    V.fromList [2, 2] @=? s
+
+calculateGradWithShape :: TF.Tensor TF.Build Float -> TF.Tensor TF.Value Float -> SessionT IO ([V.Vector Float], [V.Vector Int32])
+calculateGradWithShape y x = do
+  gs <- TF.gradients y [x]
+  xs <- TF.run gs
+  (shapes :: [V.Vector Int32]) <- mapM (TF.run . TF.shape) gs
+  return (xs, shapes)
+
 testFillGrad :: Test
 testFillGrad = testCase "testFillGrad" $ do
     [dx] <- TF.runSession $ do
@@ -436,6 +466,8 @@ main = defaultMain
             , testReluGrad
             , testReluGradGrad
             , testTanhGrad
+            , testExpandDims
+            , testReshape
             , testFillGrad
             , testTileGrad
             , testTile2DGrad