Generalise some of the lifting functions to type-changing

1 files changed, 7 insertions, 7 deletions

diff --git a/src/Data/Array/Mixed/Internal/Arith.hs b/src/Data/Array/Mixed/Internal/Arith.hs
index 0b9b8eb..579c0da 100644
--- a/src/Data/Array/Mixed/Internal/Arith.hs
+++ b/src/Data/Array/Mixed/Internal/Arith.hs
@@ -34,10 +34,10 @@ import Data.Array.Mixed.Internal.Arith.Lists
 
 
 -- TODO: test all the cases of this thing with various input strides
-liftVEltwise1 :: Storable a
+liftVEltwise1 :: (Storable a, Storable b)
               => SNat n
-              -> (VS.Vector a -> VS.Vector a)
-              -> RS.Array n a -> RS.Array n a
+              -> (VS.Vector a -> VS.Vector b)
+              -> RS.Array n a -> RS.Array n b
 liftVEltwise1 SNat f arr@(RS.A (RG.A sh (OI.T strides offset vec)))
   | Just (blockOff, blockSz) <- stridesDense sh offset strides =
       let vec' = f (VS.slice blockOff blockSz vec)
@@ -45,15 +45,15 @@ liftVEltwise1 SNat f arr@(RS.A (RG.A sh (OI.T strides offset vec)))
   | otherwise = RS.fromVector sh (f (RS.toVector arr))
 
 -- TODO: test all the cases of this thing with various input strides
-liftVEltwise2 :: Storable a
+liftVEltwise2 :: (Storable a, Storable b, Storable c)
               => SNat n
-              -> (Either a (VS.Vector a) -> Either a (VS.Vector a) -> VS.Vector a)
-              -> RS.Array n a -> RS.Array n a -> RS.Array n a
+              -> (Either a (VS.Vector a) -> Either b (VS.Vector b) -> VS.Vector c)
+              -> RS.Array n a -> RS.Array n b -> RS.Array n c
 liftVEltwise2 SNat f
     arr1@(RS.A (RG.A sh1 (OI.T strides1 offset1 vec1)))
     arr2@(RS.A (RG.A sh2 (OI.T strides2 offset2 vec2)))
   | sh1 /= sh2 = error $ "liftVEltwise2: shapes unequal: " ++ show sh1 ++ " vs " ++ show sh2
-  | product sh1 == 0 = arr1  -- if the arrays are empty, just return one of the empty inputs
+  | product sh1 == 0 = RS.A (RG.A sh1 (OI.T (0 <$ strides1) 0 VS.empty))
   | otherwise = case (stridesDense sh1 offset1 strides1, stridesDense sh2 offset2 strides2) of
       (Just (_, 1), Just (_, 1)) ->  -- both are a (potentially replicated) scalar; just apply f to the scalars
         let vec' = f (Left (vec1 VS.! offset1)) (Left (vec2 VS.! offset2))