--- a/stencil.jl	Thu Feb 21 11:40:48 2019 +0100
+++ b/stencil.jl	Thu Feb 21 14:11:08 2019 +0100
@@ -17,19 +17,17 @@
 end
 
 Base.@propagate_inbounds @inline function apply(s::Stencil{T,N}, v::AbstractVector, i::Int) where {T,N}
-    w = s.weights[1]*v[i+ s.range[1]]
+    w = s.weights[1]*v[i + s.range[1]]
     @simd for k ∈ 2:N
-        w += s.weights[k]*v[i+ s.range[1] + k-1]
+        w += s.weights[k]*v[i + s.range[1] + k-1]
     end
     return w
 end
 
-# TODO: Fix loop unrolling here as well. Then we can also remove Base.getindex(::Stencil)
-Base.@propagate_inbounds @inline function apply_backwards(s::Stencil, v::AbstractVector, i::Int)
-    w = zero(eltype(v))
-    for j ∈ s.range[2]:-1:s.range[1]
-        @inbounds weight = s[j]
-        w += weight*v[i-j]
+Base.@propagate_inbounds @inline function apply_backwards(s::Stencil{T,N}, v::AbstractVector, i::Int) where {T,N}
+    w = s.weights[N]*v[i - s.range[2]]
+    @simd for k ∈ N-1:-1:1
+        w += s.weights[k]*v[i - s.range[1] - k + 1]
     end
     return w
 end