--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/diracDiscrCurve.m	Wed Nov 20 14:26:57 2019 -0800
@@ -0,0 +1,63 @@
+% 2-dimensional delta function for single-block curvilinear grid
+% x_s:      source point coordinate vector, e.g. [x; y] or [x; y; z].
+% g:        single-block grid containing the source
+% m_order:  Number of moment conditions
+% s_order:  Number of smoothness conditions
+% order:    Order of SBP derivative approximations
+% opSet:    Cell array of function handle to opSet generator
+function d = diracDiscrCurve(x_s, g, m_order, s_order, order, opSet)
+    default_arg('order', m_order);
+    default_arg('opSet', {@sbp.D2Variable, @sbp.D2Variable});
+
+    dim = length(x_s);
+    assert(dim == 2, 'diracDiscrCurve: Only implemented for 2d.');
+    assertType(g, 'grid.Curvilinear');
+
+    % Compute Jacobian
+    J = jacobian(g, opSet, order);
+
+    % Find approximate logical coordinates of point source
+    X = g.points();
+    U = g.logic.points();
+    U_interp = scatteredInterpolant(X, U(:,1));
+    V_interp = scatteredInterpolant(X, U(:,2));
+    uS = U_interp(x_s);
+    vS = V_interp(x_s);
+
+    % Get quadrature matrices for moment conditions
+    m = g.size();
+    ops_u = opSet{1}(m(1), {0, 1}, order);
+    ops_v = opSet{2}(m(2), {0, 1}, order);
+    H_u =  ops_u.H;
+    H_v =  ops_v.H;
+
+    % Get delta function for logical grid and scale by Jacobian
+    d = (1./J).*diracDiscr(g, [uS; vS], m_order, s_order, {H_u, H_v});
+end
+
+function J = jacobian(g, opSet, order)
+    m = g.size();
+    m_u = m(1);
+    m_v = m(2);
+    ops_u = opSet{1}(m_u, {0, 1}, order);
+    ops_v = opSet{2}(m_v, {0, 1}, order);
+    I_u = speye(m_u);
+    I_v = speye(m_v);
+
+    D1_u = ops_u.D1;
+    D1_v = ops_v.D1;
+
+    Du = kr(D1_u,I_v);
+    Dv = kr(I_u,D1_v);
+
+    coords = g.points();
+    x = coords(:,1);
+    y = coords(:,2);
+
+    x_u = Du*x;
+    x_v = Dv*x;
+    y_u = Du*y;
+    y_v = Dv*y;
+
+    J = x_u.*y_v - x_v.*y_u;
+end