mul! should be complete, only thorough testing left

Author: ajozefiak

src/derivative_operators/derivative_operator_functions.jl

@@ -556,29 +556,19 @@ function LinearAlgebra.mul!(x_temp::AbstractArray{T,3}, A::AbstractDiffEqComposi
         # need to consider all dimensions and operators to determine the truncation
         # of M to x_temp
         for L in A.ops
-            if diff_axis(L) == 1
-                operating_dims[1] = 1
-            else
-                operating_dims[2] = 1
-            end
+            operating_dims[diff_axis(L)] = 1
         end
 
         x_temp_1, x_temp_2 = size(x_temp)
 
         for L in opsB
             N = diff_axis(L)
             if N == 1
-                if operating_dims[2] == 1
-                    mul!(x_temp,L,view(M,1:x_temp_1+2,1:x_temp_2), overwrite = false)
-                else
-                    mul!(x_temp,L,M, overwrite = false)
-                end
+                mul!(x_temp, L, view(M,1:x_temp_1+2,1:x_temp_2,1:x_temp_3), overwrite = false)
+            elseif N == 2
+                 mul!(x_temp, L, view(M,1:x_temp_1,1:x_temp_2+2,1:x_temp_3), overwrite = false)
             else
-                if operating_dims[1] == 1
-                    mul!(x_temp,L,view(M,1:x_temp_1,1:x_temp_2+2), overwrite = false)
-                else
-                    mul!(x_temp,L,M, overwrite = false)
-                end
+                mul!(x_temp, L, view(M,1:x_temp_1,1:x_temp_2,1:x_temp_3+2), overwrite = false)
             end
         end
 
@@ -605,15 +595,13 @@ function LinearAlgebra.mul!(x_temp::AbstractArray{T,3}, A::AbstractDiffEqComposi
 
         for L in A.ops[2:end]
             N = diff_axis(L)
-
             if N == 1
                 mul!(x_temp, L, view(M,1:x_temp_1+2,1:x_temp_2,1:x_temp_3), overwrite = false)
             elseif N == 2
                  mul!(x_temp, L, view(M,1:x_temp_1,1:x_temp_2+2,1:x_temp_3), overwrite = false)
             else
                 mul!(x_temp, L, view(M,1:x_temp_1,1:x_temp_2,1:x_temp_3+2), overwrite = false)
             end
-            
         end
     end
 end