Right stencils are mirror images of left ones after all...

Author: shivin9

src/derivative_operators/convolutions.jl

@@ -83,7 +83,7 @@ function convolve_BC_right!(x_temp::AbstractVector{T}, x::AbstractVector{T}, A::
             slen = length(A.stencil_coefs)
             L = A.stencil_length
         else
-            cur_stencil = stencil[end-i+1]
+            cur_stencil = stencil[i]
             slen = length(cur_stencil)
         end
 
@@ -96,7 +96,7 @@ function convolve_BC_right!(x_temp::AbstractVector{T}, x::AbstractVector{T}, A::
             xtempi += cur_coeff * cur_stencil[idx] * x[N-L+idx]
         end
         # @show xtempi*(1/(A.dx^A.derivative_order))
-        x_temp[end-i+1] = xtempi
+        x_temp[end-_bpc+i] = xtempi
     end
 end
 
@@ -206,7 +206,7 @@ function convolve_BC_right!(x_temp::AbstractVector{T}, _x::BoundaryPaddedVector,
             cur_stencil = A.stencil_coefs
             slen = length(A.stencil_coefs)
         else
-            cur_stencil = stencil[end-i+1]
+            cur_stencil = stencil[i]
             slen = length(cur_stencil)
         end
 
@@ -222,6 +222,6 @@ function convolve_BC_right!(x_temp::AbstractVector{T}, _x::BoundaryPaddedVector,
         #     xtempi += cur_coeff * cur_stencil[idx] * _x.u[end-L+idx+1]
         # end
 
-        x_temp[N-i+1] = xtempi
+        x_temp[end-_bpc+i] = xtempi
     end
 end

src/derivative_operators/derivative_operator.jl

@@ -38,7 +38,7 @@ function CenteredDifference{N}(derivative_order::Int,
     low_boundary_coefs      = convert(SVector{boundary_point_count},_low_boundary_coefs)
 
     _high_boundary_coefs    = SVector{boundary_stencil_length, T}[convert(SVector{boundary_stencil_length, T}, (1/dx^derivative_order) * calculate_weights(derivative_order, oneunit(T)*x0, reverse(right_boundary_x))) for x0 in R_boundary_deriv_spots]
-    high_boundary_coefs      = convert(SVector{boundary_point_count},_high_boundary_coefs)
+    high_boundary_coefs      = convert(SVector{boundary_point_count},reverse(_high_boundary_coefs))
 
     coefficients            = coeff_func isa Nothing ? nothing : Vector{T}(undef,len)
     DerivativeOperator{T,N,false,T,typeof(stencil_coefs),

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([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)
+    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)
 
     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

@@ -11,8 +11,8 @@ 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([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)
+    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)
 
     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]