dan@0: % solve multiple 2nd degree linear systems at once - no pivoting!
dan@0: function dg2 = lin_solve_dgr_2(A,b,R)
dan@0: nrm =  (-A(2,1,:) .* A(1,2,:) + A(1,1,:) .* A(2,2,:));
dan@0:   dg2 = zeros(2,R);
dan@0:   dg2(1,:) = -(b(2,1,:) .* A(1,2,:) - b(1,1,:) .* A(2,2,:)) ./ nrm;
dan@0:   dg2(2,:) = -(b(1,1,:) .* A(2,1,:) - b(2,1,:) .* A(1,1,:)) ./ nrm;
dan@0: end