--- a/+scheme/Utux.m	Wed Aug 07 13:28:21 2019 +0200
+++ b/+scheme/Utux.m	Wed Aug 07 15:23:42 2019 +0200
@@ -68,26 +68,23 @@
         %       neighbour_boundary  is a string specifying which boundary to interface to.
         function [closure, penalty] = boundary_condition(obj,boundary,type)
             default_arg('type','dirichlet');
-            sigma_left = -1; % Scalar penalty parameter for left boundary
-            sigma_right = 1; % Scalar penalty parameter for right boundary
+            s = obj.getBoundarySign(boundary);
+            e = obj.getBoundaryOperator('e', boundary);
             switch boundary
                 % Can only specify boundary condition where there is inflow
                 % Extract the postivie resp. negative part of a, for the left
                 % resp. right boundary, and set other values of a to zero.
                 % Then the closure will effectively only contribute to inflow boundaries
-                case {'l','L','left','Left'}
+                case {'l'}
                     a_inflow = obj.a;
                     a_inflow(a_inflow < 0) = 0;
-                    tau = sigma_left*a_inflow*obj.e_l;
-                    closure = obj.Hi*tau*obj.e_l';
-                case {'r','R','right','Right'}
+                case {'r'}
                     a_inflow = obj.a;
                     a_inflow(a_inflow > 0) = 0;
-                    tau = sigma_right*a_inflow*obj.e_r;
-                    closure = obj.Hi*tau*obj.e_r';
             end
+            tau = s*a_inflow*e;
+            closure = obj.Hi*tau*e';
             penalty = -obj.Hi*tau;
-
          end
 
          function [closure, penalty] = interface(obj, boundary, neighbour_scheme, neighbour_boundary, type)
@@ -105,19 +102,43 @@
 
          end
 
+        % Returns the boundary sign. The right boundary is considered the positive boundary
+        % boundary -- string
+        function s = getBoundarySign(obj, boundary)
+            assertIsMember(boundary, {'l', 'r'})
+
+            switch boundary
+                case {'r'}
+                    s = 1;
+                case {'l'}
+                    s = -1;
+            end
+        end
+
+        % Returns the boundary operator op for the boundary specified by the string boundary.
+        % op        -- string
+        % boundary  -- string
+        function o = getBoundaryOperator(obj, op, boundary)
+            assertIsMember(op, {'e'})
+            assertIsMember(boundary, {'l', 'r'})
+
+            o = obj.([op, '_', boundary]);
+        end
+
+        % Returns square boundary quadrature matrix, of dimension
+        % corresponding to the number of boundary points
+        %
+        % boundary -- string
+        % Note: for 1d diffOps, the boundary quadrature is the scalar 1.
+        function H_b = getBoundaryQuadrature(obj, boundary)
+            assertIsMember(boundary, {'l', 'r'})
+
+            H_b = 1;
+        end
+
         function N = size(obj)
             N = obj.m;
         end
 
     end
-
-    methods(Static)
-        % Calculates the matrices needed for the inteface coupling between boundary bound_u of scheme schm_u
-        % and bound_v of scheme schm_v.
-        %   [uu, uv, vv, vu] = inteface_coupling(A,'r',B,'l')
-        function [uu, uv, vv, vu] = interface_coupling(schm_u,bound_u,schm_v,bound_v)
-            [uu,uv] = schm_u.interface(bound_u,schm_v,bound_v);
-            [vv,vu] = schm_v.interface(bound_v,schm_u,bound_u);
-        end
-    end
-end
\ No newline at end of file
+end