| ® | 8 | 16 | 32 | 64 |
| ® | 0.243341 E−2 | 0.829697 E−3 | 0.285754 E−3 | 0.994597 E−4 |
| ® | 0.179737 E−3 | 0.469229 E−4 | 0.119436 E−4 | 0.300920 E−5 |
at the nodes | ® | 0.172473 E−2 | 0.446493 E−3 | 0.112615 E−3 | 0.282163 E−4 |