1.3 Structure of a Classic FEM Framework Program

A classic FEM framework program consists of two subroutines: init() and driver(). init() is called by the FEM framework only on the first processor - this routine typically does specialized I/O, startup and shutdown tasks. driver() is called for every chunk on every processor, and does the main work of the program. In the language of the TCHARM manual, init() runs in the serial context, and driver() runs in the parallel context.

     subroutine init
          read the serial mesh and configuration data
     end subroutine
/* after init, the FEM framework partitions the mesh */
     subroutine driver
          get local mesh chunk
          time loop
               FEM computations
               communicate boundary conditions
               more FEM computations
          end time loop
     end subroutine

In this mode, the FEM framework sets up a default writing mesh during init(), partitions the mesh after init(), and sets up the partitioned mesh as the default reading mesh during driver().