added stride for pooling in tracker

Author: tejank10

src/tracker/array.jl

@@ -242,21 +242,21 @@ function back(::typeof(_conv), Δ, x, w, stride, pad)
   @back(w, NNlib.∇conv_filter(Δ, data(x), data(w); stride = stride, pad = pad))
 end
 
-_maxpool(x, k, pad) = maxpool(x, k; pad = pad)
+_maxpool(x, k, pad, stride) = maxpool(x, k; pad = pad, stride = stride)
 
-maxpool(x::TrackedArray, k; pad = map(_->0,k)) =
-  track(_maxpool, x, k, pad)
+maxpool(x::TrackedArray, k; pad = map(_->0,k), stride = k) =
+  track(_maxpool, x, k, pad, stride)
 
-back_(::typeof(_maxpool), y, Δ, x, k, pad) =
-  back(x, NNlib.∇maxpool(Δ, y, data(x), k, pad=pad))
+back_(::typeof(_maxpool), y, Δ, x, k, pad, stride) =
+  back(x, NNlib.∇maxpool(Δ, y, data(x), k, pad=pad, stride=stride))
 
-_meanpool(x, k, pad) = meanpool(x, k; pad = pad)
+_meanpool(x, k, pad, stride) = meanpool(x, k; pad = pad, stride = stride)
 
-meanpool(x::TrackedArray, k; pad = map(_->0,k)) =
-  track(_meanpool, x, k, pad)
+meanpool(x::TrackedArray, k; pad = map(_->0,k), stride = k) =
+  track(_meanpool, x, k, pad, stride)
 
-back_(::typeof(_meanpool), y, Δ, x, k, pad) =
-  back(x, NNlib.∇meanpool(Δ, y, data(x), k, pad=pad))
+back_(::typeof(_meanpool), y, Δ, x, k, pad, stride) =
+  back(x, NNlib.∇meanpool(Δ, y, data(x), k, pad=pad, stride=stride))
 
 # Broadcasting