Multiple Time Chunks

[jbschroder]

This issue is meant as a place-holder, so that we don't forget our discussion on how to handle multiple time-chunks in XBraid.

• There is a branch that implements multiple time-chunks (called timechunks) that is integrated into Stefanie's SU2 code. This branch takes in a numchunks integer from the user, and then breaks the time-domain in numchunks evenly spaced sub-intervals. XBraid is then run on each subinterval.
• Rob and I thought that there might be a more general way of doing this, namely having the user specify something like a maximum number of time-points allowed. Then, the time-domain would be split up this way.
• We in particular liked this approach, because the reason for doing time-chunks is to save memory, and number of time-points is more natural way to "count" memory usage. One could even weight each time-point, similar to the load balancing strategy.
• Additionally, a max-num-time-points parameter could be integrated into FRefine.