How Cactus Calls Scheduled Functions

For each scheduled function called, the flesh performs a variety of jobs at entry and exit.

On entry to a scheduled routine, if the routine is being called at the CCTK_ANALYSIS timebin first, a check is made to see if the routine should actually be called on this timestep. For this, all grid variables in the trigger groups for the routine are checked with all registered output methods to determine if it is time to output any triggers. The routine will only be called if at least one is due to be output. Note that once a grid variable has been analyzed, it gets marked as such, and will not be analyzed again during this iteration. (Note that a routine without any trigger groups will also be called.) Thus, if more than one analysis routine should be triggered on the same trigger variable(s), they must be scheduled in a single group. Routines from all timebins, other than ANALYSIS, are always called.

Next, storage is assigned for any required variables, remembering the original state of storage.

The routine is then called, and on exit, any required grid variables are first synchronised. Following synchronization, any required output methods are called for the triggers. Finally, the storage of grid variables is returned to the original state.