call Simulation_computeAnalytical(integer(IN) :: blockID, real(IN) :: tcurr)
Compute an analytical solution. This is simulation-dependent, there is no general implementation.
blockID - the number of the block to initialize tcurr - current time
The analytical solution is computed and stored in an appropriate slot (or slots) in the solution vector, UNK.
By default this is just a stub that doesn't do anything.