This function select the start generating node as the one with the highest x coordinate and the end as the node with the lowest
get_generating(panicle)
| panicle | a panicle graph. |
|---|
This approach is prone to error is the panicle is not orientated from right to left in the P-TRAP picture.
This function is used and improved by `get_base()`, which select the base node as the generating node with no parents