Fix open issues with slice-gradient

Author: erikabor

tensorflow-ops/src/TensorFlow/Gradient.hs

@@ -711,7 +711,7 @@ opGrad "Pad" _ [toT -> x, toT -> padPattern] [dz] =
     gradientSliceSize = shape (x :: Tensor Build Float)
 
 -- Gradient for Slice
--- Create an Nx2 padding where N ist the rank of (grad of) Slice and the first
+-- Create an Nx2 padding where N is the rank of (grad of) Slice and the first
 -- column represents how many zeros are to be prepended for each dimension, and the second
 -- column indicates how many zeros are appended.
 -- The number of zeros to prepend is the shape of the beginvec.
@@ -723,13 +723,13 @@ opGrad "Slice" _ [toT -> inputvec, toT -> beginvec, _] [dz] =
    [Just $ CoreOps.pad dz paddings, Nothing, Nothing]
   where
     v1 = vector [1 :: Int32]
-    input_rank' = CoreOps.rank (inputvec :: Tensor Build Float)
-    -- For some reason input_rank' has an empty shape
-    input_rank = CoreOps.reshape input_rank' v1
-    pad_shape = CoreOps.concat 0 [input_rank, v1]
-    beforepad = CoreOps.reshape beginvec pad_shape
-    afterpad = CoreOps.reshape (shape inputvec - shape dz - beginvec) pad_shape
-    paddings = CoreOps.concat 1 [beforepad, afterpad]
+    inputRank' = CoreOps.rank (inputvec :: Tensor Build Float)
+    -- For some reason inputRank' has an empty shape
+    inputRank = CoreOps.reshape inputRank' v1
+    padShape = CoreOps.concat 0 [inputRank, v1]
+    beforePad = CoreOps.reshape beginvec padShape
+    afterPad = CoreOps.reshape (shape inputvec - shape dz - beginvec) padShape
+    paddings = CoreOps.concat 1 [beforePad, afterPad]
 
 -- TODO: This could be either Int32 or Int64.
 opGrad "BatchToSpaceND" _ [_, toT @Int32 -> blockShape, toT @Int32 -> crops] [dz] =

tensorflow-ops/tests/GradientTest.hs

@@ -342,7 +342,14 @@ testSlice =
         (z :: TF.Tensor TF.Value Float) <- TF.render $ TF.zeros $ TF.Shape [1, 2, 2 :: Int64]
         let y = TF.slice x (TF.constant (TF.Shape [3]) [1, 1, 1 :: Int32]) (TF.shape z)
         calculateGradWithShape y x
-    V.fromList [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 1, 1, 0] @=? dx
+    let expected =
+         [0, 0, 0, 0,
+          0, 0, 0, 0,
+          0, 0, 0, 0,
+          0, 0, 0, 0,
+          0, 1, 1, 0,
+          0, 1, 1, 0]
+    V.fromList expected @=? dx
     V.fromList [2, 3, 4] @=? s
 
 testBatchToSpaceND :: Test