Basic HTML version of Foils prepared 10 Oct 1995

Foil 34 Derived Datatype Basics

From Fox Presentation Fall 1995 CPS615 Basic Simulation Track for Computational Science -- Fall Semester 95. by Geoffrey C. Fox


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



© on Tue Oct 7 1997