Try different block configuration for copyto!

src/Operators/finitedifference.jl

@@ -3437,19 +3437,21 @@ function Base.copyto!(
         Nq = 1
         Nh = 1
     end
-    bounds = window_bounds(space, bc)
+    (li, lw, rw, ri) = bounds = window_bounds(space, bc)
+    nnodes = ri - li + 1
     args = (
         strip_space(out, space),
         strip_space(bc, space),
         axes(out),
         bounds,
+        nnodes,
         Nq,
         Nh,
     )
     kernel = @cuda launch = false copyto_stencil_kernel!(args...)
     kernel_config = CUDA.launch_configuration(kernel.fun)
     max_threads = kernel_config.threads
-    nitems = Nq * Nq * Nh
+    nitems = nnodes * Nq * Nq * Nh
     nthreads = min(max_threads, nitems)
     nblocks = cld(nitems, nthreads)
     # executed
@@ -3460,14 +3462,33 @@ function Base.copyto!(
     return out
 end
 
-function copyto_stencil_kernel!(out, bc, space, bds, Nq, Nh)
+function copyto_stencil_kernel!(out, bc, space, bds, nnodes, Nq, Nh)
     gid = threadIdx().x + (blockIdx().x - 1) * blockDim().x
-    if gid ≤ Nq * Nq * Nh
-        h = cld(gid, Nq * Nq)
-        j = cld(gid - (h - 1) * Nq * Nq, Nq)
-        i = gid - (h - 1) * Nq * Nq - (j - 1) * Nq
+    if gid ≤ nnodes * Nq * Nq * Nh
+        (li, lw, rw, ri) = bds
+        h = cld(gid, nnodes * Nq * Nq)
+        j = cld(gid - (h - 1) * nnodes * Nq * Nq, nnodes * Nq)
+        i = cld(
+            gid - (h - 1) * nnodes * Nq * Nq - (j - 1) * nnodes * Nq,
+            nnodes,
+        )
+        ndidx =
+            gid - (h - 1) * nnodes * Nq * Nq - (j - 1) * nnodes * Nq -
+            (i - 1) * nnodes
         hidx = (i, j, h)
-        apply_stencil!(space, out, bc, hidx, bds)
+        #apply_stencil!(space, out, bc, hidx, bds)
+        fun =
+            !Topologies.isperiodic(Spaces.vertical_topology(space)) ?
+            (
+                ndidx ≤ lw - 1 ?
+                LeftBoundaryWindow{Spaces.left_boundary_name(space)}() :
+                (
+                    ndidx ≥ rw + 1 ?
+                    RightBoundaryWindow{Spaces.right_boundary_name(space)}() :
+                    Interior()
+                )
+            ) : Interior()
+        setidx!(space, out, ndidx, hidx, getidx(space, bc, fun, ndidx, hidx))
     end
     return nothing
 end