3basis[0 * 3 + 1] = 0.5 * (ss - 1.0);
6basis[1 * 3 + 0] = 0.5 * (1.0 + rr);
10basis[2 * 3 + 0] = 0.0;
11basis[2 * 3 + 1] = 0.5 * (1.0 + ss);
12basis[2 * 3 + 2] = 0.0;
14basis[3 * 3 + 0] = 0.5 * (rr - 1.0);
15basis[3 * 3 + 1] = 0.0;
16basis[3 * 3 + 2] = 0.0;