--- a/diffOp.jl	Mon Dec 17 16:30:39 2018 +0100
+++ b/diffOp.jl	Mon Dec 17 16:35:08 2018 +0100
@@ -16,7 +16,7 @@
     error("not implemented")
 end
 
-function interface(Du::DiffOp, Dv::DiffOp, b::BoundaryID; type)
+function interface(Du::DiffOp, Dv::DiffOp, b::grid.BoundaryId; type)
     error("not implemented")
 end
 
@@ -29,19 +29,23 @@
 end
 
 # u = L*v
-function apply(L::Laplace1D, u::AbstractVector, v::AbstractVector)::AbstractVector
+function apply(L::Laplace1D, u::AbstractVector, v::AbstractVector)
     N = closureSize(L.op)
     M = length(v)
 
+    h = scaling(L.grid)
+
     for i ∈ 1:N
-        u[i] = apply(L.op.closureStencils[i], v, i)
+        u[i] = apply(L.op.closureStencils[i], v, i)/h^2
     end
 
     for i ∈ N+1:M-N
-        u[i] = apply(L.op.innerStencil, i);
+        u[i] = apply(L.op.innerStencil, i)/h^2
     end
 
     for i ∈ M:-1:M-N+1
-        u[i] = apply(flip(L.op.closureStencils[M-i+1]), v, i)
+        u[i] = apply(flip(L.op.closureStencils[M-i+1]), v, i)/h^2
     end
+
+    return nothing
 end