HDX: "heat diffusion" solver AV

[jteresco]

Idea: use METAL graphs to set some initial and boundary conditions and do a heat diffusion AV.

[jteresco]

Given the work on a C version of this on METAL graphs, @MikePlekan would be good to be involved here.

[jteresco]

It would be nice to make a direct correlation to the fact that the data represents highway systems. But a first pass with "temperatures" at each waypoint whose temperature in the next iteration depends on its own temperature and that of its neighbors could be instructive. And it will be a great example for a distributed computation when the efforts to have parallel AVs have matured.