3 Writing F90 Program

To start, you need to create a Fortran Module to represent a chare, e.g. {ChareName}Mod.

      ## Just replace Hello throughout with your chare's name. ##
      ## and add your chare's personal data below where indicated ##
      ## Everything else remains the same ##
      MODULE HelloMod

      TYPE Hello
      ## your chare's data goes here ##
      integer data
      END TYPE

      TYPE HelloPtr
      TYPE (Hello), POINTER ::  obj
      integer*8 aid
      END TYPE

      END MODULE

In the Fortran file you must write an allocate funtion for this chare with the name: Hello_allocate.

      ## Just replace Hello throughout with your chare's name. ##
      ## Everything else remains the same ##
      SUBROUTINE Hello_allocate(objPtr, aid, index)
      USE HelloMod
      TYPE(HelloPtr) objPtr 
      integer*8 aid
      integer index

      allocate(objPtr%obj)
      objPtr%aid = aid;
      ## you can initialize the Chare user data here
      objPtr%obj%data = index
      END SUBROUTINE

Now that you have the chare and the chare constructor function, you can start to write one or more entry functions as declared in .ci files.

      ## p1, p2, etc represent user parameters
      ## the "objPtr, myIndex" stuff is required in every Entry Point.
      ## CkExit() must be called by the chare to terminate.
      SUBROUTINE SayHi(objPtr, myIndex, data, data2, len, s)
      USE HelloMod
      IMPLICIT NONE

      TYPE(HelloPtr) objPtr
      integer myIndex
      integer data
      double precision data2
      integer len
      integer s(len)

      objPtr%obj%data = 20
      if (myIndex < 4) then
          call SendTo_Hello_SayHi(objPtr%aid, myIndex+1, 1, data2, len, s);
      else 
          call CkExit()
      endif

Now, you can write the main program to create the chare array and start the program by sending the first message.

      SUBROUTINE f90charmmain()
      USE HelloMod
      integer i
      double precision d
      integer*8 aid
      integer  s(8)

      call Hello_CkNew(5, aid)

      call set_ChunkSize(10);

      do i=1,8
          s(i) = i;
      enddo
      d = 2.50
      call SendTo_Hello_SayHi(aid, 0, 1, d, 4, s(3:6));

      END

This main program creates an chare array Hello of size 5 and send a message with an integer, an double and array of integers to the array element of index 0.