Separate HTML for Basic Foil 38 Use of Derived Types in Jacobi Iteration with Guard Rings--II

Basic HTML version of Foils prepared 10 Oct 1995

Foil 38 Use of Derived Types in Jacobi Iteration with Guard Rings--II

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

integer North,South,East,West

# These are the processor ranks of 4 nearest neighbors

integer rowtype,coltype # the new derived types

# Fortran stores elements in columns contiguously

# (C has opposite convention!)

call MPI_TYPE_CONTIGUOUS(NLOC, MPI_REAL, coltype, ierr)

call MPI_TYPE_COMMIT(coltype,ierr)

# rows (North and South) are not contiguous

call MPI_TYPE_VECTOR(NLOC, 1, NLOC2, MPI_REAL, rowtype, ierr)

call MPI_TYPE_COMMIT(rowtype,ierr)

call MPI_SEND(array(2,2), 1, coltype, west,0,comm,ierr)

call MPI_SEND(array(2,NLOC+1), 1, coltype, east,0,comm,ierr)

call MPI_SEND(array(2,2), rowtype, north, 0,comm,ierr)

call MPI_SEND(array(NLOC+1,2), 1, rowtype, south, 0,comm,ierr)