16 const double L1 = x[0];
17 const double L2 = x[1];
18 const double t = x[2];
19 N[0] = 0.5 * (1.0 - L1 - L2) * (1.0 - t);
20 N[1] = 0.5 * L1 * (1.0 - t);
21 N[2] = 0.5 * L2 * (1.0 - t);
22 N[3] = 0.5 * (1.0 - L1 - L2) * (1.0 + t);
23 N[4] = 0.5 * L1 * (1.0 + t);
24 N[5] = 0.5 * L2 * (1.0 + t);