Why Is the Current State-of-the-
art Not Adequate?
1. Time advance scheme is too inefficient
    - Every cell is updated regardless of whether a
change has occurred
      - Time step is not based on local conditions
2. Existing time advance schemes do not
allow code-code coupling
3. The “curse” of Courant condition
    - physically the system should be stable if there is
no change regardless of how fast information is
propagating but numerically it is not