22{
23 dN[0] = (r[0] + 0.5) * r[1] * (r[1] + 1) / 2;
24 dN[1] = (r[0] - 0.5) * r[1] * (r[1] + 1) / 2;
25 dN[2] = (r[0] - 0.5) * r[1] * (r[1] - 1) / 2;
26 dN[3] = (r[0] + 0.5) * r[1] * (r[1] - 1) / 2;
27 dN[4] = -r[0] * r[1] * (1 + r[1]);
28 dN[5] = (1 - r[1] * r[1]) * (r[0] - 0.5);
29 dN[6] = r[0] * r[1] * (1 - r[1]);
30 dN[7] = (1 - r[1] * r[1]) * (r[0] + 0.5);
31 dN[8] = 2 * r[0] * (r[1] * r[1] - 1);
32
33 dN[10] = (r[1] + 0.5) * r[0] * (r[0] - 1) / 2;
34 dN[11] = (r[1] - 0.5) * r[0] * (r[0] - 1) / 2;
35 dN[12] = (r[1] - 0.5) * r[0] * (r[0] + 1) / 2;
36 dN[13] = (1 - r[0] * r[0]) * (r[1] + 0.5);
37 dN[14] = r[0] * r[1] * (1 - r[0]);
38 dN[15] = (1 - r[0] * r[0]) * (r[1] - 0.5);
39 dN[16] = -r[0] * r[1] * (1 + r[0]);
40 dN[17] = 2 * r[1] * (r[0] * r[0] - 1);
41 dN[9] = (r[1] + 0.5) * r[0] * (r[0] + 1) / 2;
42}