--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/+sbp/D1Gauss.m	Wed Feb 08 09:18:08 2017 +0100
@@ -0,0 +1,41 @@
+classdef D1Gauss < sbp.OpSet
+    % Diagonal-norm SBP operators based on the Gauss quadrature formula
+    % with m nodes, which is of degree 2m-1. Hence, The operator D1 is
+    % accurate of order m.
+    properties
+        D1 % SBP operator approximating first derivative
+        H % Norm matrix
+        HI % H^-1
+        Q % Skew-symmetric matrix
+        e_l % Left boundary operator
+        e_r % Right boundary operator
+        m % Number of grid points.
+        h % Step size
+        x % grid
+        borrowing % Struct with borrowing limits for different norm matrices
+    end
+
+    methods
+        function obj = D1Gauss(m,lim)
+
+            x_l = lim{1};
+            x_r = lim{2};
+            L = x_r-x_l;
+
+            switch m
+                case 4
+                    [obj.D1,obj.H,obj.x,obj.h,obj.e_l,obj.e_r] = ...
+                        sbp.implementations.d1_gauss_4(L);
+                otherwise
+                    error('Invalid number of points: %d.', m);
+            end
+
+
+            obj.x = obj.x + x_l;
+            obj.HI = inv(obj.H);
+            obj.Q = obj.H*obj.D1 - obj.e_r*obj.e_r' + obj.e_l*obj.e_l';
+
+            obj.borrowing = [];
+        end
+    end
+end