I'm trying to implement an interactive graph visualisation tool using matplotlib.
I want to use a spring layout, where nodes repulse each other and edges act as springs to pull connected nodes together. Usually, this algorithm runs through a number of iterations of attraction/repulsion to allow the nodes to converge to suitable positions. However, rather than running all these iterations to lay out the graph and then rendering it, I want to animate the graph as it is "springing" into place, and then allow the user to drag nodes around and have the graph redraw on the fly. My idea for doing this was to use a generator function, where I yield the position of the nodes after each iteration and then call draw() on the position yielded. Does this seem like a sensible approach? The problem is that the node positions that are being operated on by the generator function may be altered by user input - dragging the nodes - and I'm not sure if this will break the way that the new positions are yielded. How do I use a generator function that might stop (when the nodes stop moving) but then need to restart again (once the user moves the nodes)? I'm quite an experienced Python programmer but I've never taken the trouble to get my head around generator functions, so any guidance welcome! Peter -- http://mail.python.org/mailman/listinfo/python-list
