Typically use of variables is as follows:
| program variable | meaning |
| element | global element number. |
| max_element | highest global element number. |
| inod | global node number. |
| max_node | highest global node number. |
| inol | element node number. |
| nnol | the number of element nodes. |
| ipuknwn | primary unknown number. |
| npuknwn | the number of primary unknowns. |
| iuknwn | unknown number. |
| nuknwn | the number of unknowns. |