07-Jan-2022 20:00:30 fem2d_bvp_quadratic_test(): MATLAB/Octave version 9.8.0.1380330 (R2020a) Update 2 Test fem2d_bvp_quadratic(). FEM2D_BVP_QUADRATIC_TEST01 Solve - del ( A del U ) + C U = F on the unit square with zero boundary conditions. A1(X,Y) = 1.0 C1(X,Y) = 0.0 F1(X,Y) = 2*X*(1-X)+2*Y*(1-Y). U1(X,Y) = X * ( 1 - X ) * Y * ( 1 - Y ) The grid uses 5 by 5 nodes. I J X Y U Uexact Error 1 1 0.000000 0.000000 0.000000 0.000000 0.000000e+00 2 1 0.250000 0.000000 0.000000 0.000000 0.000000e+00 3 1 0.500000 0.000000 0.000000 0.000000 0.000000e+00 4 1 0.750000 0.000000 0.000000 0.000000 0.000000e+00 5 1 1.000000 0.000000 0.000000 0.000000 0.000000e+00 1 2 0.000000 0.250000 0.000000 0.000000 0.000000e+00 2 2 0.250000 0.250000 0.035156 0.035156 2.081668e-17 3 2 0.500000 0.250000 0.046875 0.046875 4.857226e-17 4 2 0.750000 0.250000 0.035156 0.035156 2.775558e-17 5 2 1.000000 0.250000 0.000000 0.000000 0.000000e+00 1 3 0.000000 0.500000 0.000000 0.000000 0.000000e+00 2 3 0.250000 0.500000 0.046875 0.046875 3.469447e-17 3 3 0.500000 0.500000 0.062500 0.062500 2.775558e-17 4 3 0.750000 0.500000 0.046875 0.046875 2.081668e-17 5 3 1.000000 0.500000 0.000000 0.000000 0.000000e+00 1 4 0.000000 0.750000 0.000000 0.000000 0.000000e+00 2 4 0.250000 0.750000 0.035156 0.035156 2.081668e-17 3 4 0.500000 0.750000 0.046875 0.046875 3.469447e-17 4 4 0.750000 0.750000 0.035156 0.035156 2.081668e-17 5 4 1.000000 0.750000 0.000000 0.000000 0.000000e+00 1 5 0.000000 1.000000 0.000000 0.000000 0.000000e+00 2 5 0.250000 1.000000 0.000000 0.000000 0.000000e+00 3 5 0.500000 1.000000 0.000000 0.000000 0.000000e+00 4 5 0.750000 1.000000 0.000000 0.000000 0.000000e+00 5 5 1.000000 1.000000 0.000000 0.000000 0.000000e+00 l1 error = 1.02696e-17 L2 error = 1.99561e-17 H1S error = 1.05501e-16 fem2d_bvp_quadratic_test(): Normal end of execution. 07-Jan-2022 20:00:30