Derived Datatype Basics
Derived Datatypes should be declared integer in Fortran and MPI_Datatype in C
Generally have form { (type0,disp0), (type1,disp1) ... (type(n-1),disp(n-1)) } with list of primitive data types typei and displacements (from start of buffer) dispi
call MPI_TYPE_CONTIGUOUS (count, oldtype, newtype, ierr)
- creates a new datatype newtype made up of count repetitions of old datatype oldtype
one must use call MPI_TYPE_COMMIT(derivedtype, ierr) before one can use the type derivedtype in a communication call
call MPI_TYPE_FREE(derivedtype, ierr) frees up space used by this derived type