--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/+sbp/+implementations/d2_variable_periodic_2.m	Fri Jul 27 10:31:51 2018 -0700
@@ -0,0 +1,50 @@
+function [H, HI, D1, D2, e_l, e_r, d1_l, d1_r] = d2_variable_periodic_2(m,h)
+    % m = number of unique grid points, i.e. h = L/m;
+
+    if(m<3)
+        error(['Operator requires at least ' num2str(3) ' grid points']);
+    end
+
+    % Norm
+    Hv = ones(m,1);
+    Hv = h*Hv;
+    H = spdiag(Hv, 0);
+    HI = spdiag(1./Hv, 0);
+
+
+    % Dummy boundary operators
+    e_l = sparse(m,1);
+    e_r = rot90(e_l, 2);
+
+    d1_l = sparse(m,1);
+    d1_r = -rot90(d1_l, 2);
+
+    % D1 operator
+    diags   = -1:1;
+    stencil = [-1/2 0 1/2];
+    D1 = stripeMatrixPeriodic(stencil, diags, m);
+    D1 = D1/h;
+
+    scheme_width = 3;
+    scheme_radius = (scheme_width-1)/2;
+
+    r = 1:m;
+    offset = scheme_width;
+    r = r + offset;
+
+    function D2 = D2_fun(c)
+        c = [c(end-scheme_width+1:end); c; c(1:scheme_width) ];
+
+        Mm1 = -c(r-1)/2 - c(r)/2;
+        M0  =  c(r-1)/2 + c(r)   + c(r+1)/2;
+        Mp1 =            -c(r)/2 - c(r+1)/2;
+
+        vals = [Mm1,M0,Mp1];
+        diags = -scheme_radius : scheme_radius;
+        M = spdiagsPeriodic(vals,diags);
+
+        M=M/h;
+        D2=HI*(-M );
+    end
+    D2 = @D2_fun;
+end
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