Merging upstream code

Author: shivin9

test/bc_coeff_compositions.jl

@@ -6,8 +6,8 @@ function fourth_deriv_approx_stencil(N)
     A[1,1:8] = [3.5 -56/3 42.5 -54.0 251/6 -20.0 5.5 -2/3]
     A[2,1:8] = [2/3 -11/6 0.0 31/6 -22/3 4.5 -4/3 1/6]
 
-    A[N-1,N-5:end] = reverse([2/3 -11/6 0.0 31/6 -22/3 4.5 -4/3 1/6], dims=2)
-    A[N,N-5:end] = reverse([3.5 -56/3 42.5 -54.0 251/6 -20.0 5.5 -2/3], dims=2)
+    A[N-1,N-5:end] = reverse([3.5 -56/3 42.5 -54.0 251/6 -20.0 5.5 -2/3], dims=2)
+    A[N,N-5:end] = reverse([2/3 -11/6 0.0 31/6 -22/3 4.5 -4/3 1/6], dims=2)
 
     for i in 3:N-2
         A[i,i-2:i+4] = [-1/6 2.0 -13/2 28/3 -13/2 2.0 -1/6]

test/derivative_operators_interface.jl

@@ -40,7 +40,6 @@ function second_derivative_stencil(N)
   A
 end
 
-# Broken?
 function convert_by_multiplication(::Type{Array}, A::AbstractDerivativeOperator{T}, N::Int=A.dimension) where T
     @assert N >= A.stencil_length # stencil must be able to fit in the matrix
     mat = zeros(T, (N, N+2))