Restructuring the Model

The ribbon in the original C code was represented by an array of ribbon segments, which act like a set of masses connected with springs. The simulation typically works sequentially through the list, with a couple of places where pairs of adjacent points are processed.

In the model, the climbers are held in a separate data structure. There is a little book keeping to determine which ribbon segment the climber is attached to, and then the climber forces on the ribbon due to acceleration are computed and applied. The ribbon forces on the climber are approximated, with a tendency to move the climber towards the ribbon if it starts drifting away.

If the representation of the ribbon was moved from an array to a linked list, then the climbers could be added into the list between ribbon segments. The climbers would become very short ribbon segments with a higher mass, and the length and tension of the segments above and below each climber would be adjusted to represent the climber moving along the ribbon. The existing ribbon and point dynamics routines would then be used to compute the ribbon effects on the climber.

Java has a LinkedList class that is part of the AbstractCollection class, so it should be fairly quick.