Subsections

6.7 Non-Replicated Variable Arrays

For each non-replicated variable array defined in the Config file (see Sec:ConfigFileSyntax), various macros and constants are defined to assist the user in retrieving the information from the NONREP line as well as determining the distribution of array element variables across the meshes.

6.7.1 Per-Array Macros

For each non-replicated variable array FOO as defined by the following Config line:

NONREP unktype FOO localmax globalparam ioformat

the following will be placed into Flash.h:

#define FOO_NONREP
An integer constant greater than zero to be used as an id for this array. The user should rarely ever need to use this value. Instead, it is much more likely that the user would just query the preprocessor for the existence of this symbol (via #ifdef FOO_NONREP) to enable sections of code.
#define FOO_NONREP_LOC2UNK(loc)
Given the 1-based index into this mesh's local subset of the global array, returns the UNK index where that variable is stored.
#define FOO_NONREP_MAXLOCS
The integer constant localmax as supplied in the Config file NONREP line.
#define FOO_NONREP_RPCOUNT
The string literal value of globalparam from the NONREP line.

6.7.2 Array Partitioning Macros

These are the macros used to calculate the subset of indices into the global variable array each mesh is responsible for:

#define NONREP_NLOCS(mesh,meshes,globs)
Returns the number of elemenets in the mesh's local subset. This value will always be less than or equal to FOO_NONREP_MAXLOCS.
#define NONREP_LOC2GLOB(loc,mesh,meshes)
Maps an index into a mesh's local subset to its index in the global array.
#define NONREP_GLOB2LOC(glob,mesh,meshes)
Maps an index of the global array to the index into a mesh's local subset. If the mesh provided does not have that global element the result is undefined.
#define NONREP_MESHOFGLOB(glob,meshes)
Returns the mesh that owns a given global array index.

Descriptions of arguments to the above macros:

loc: 1-based index into the mesh-local subset of the global array's indices.
glob: 1-based index into the global array.
globs: Length of the global array. This should be the value read from the array's runtime parameter FOO_NONREP_RPCOUNT.
mesh: 0-based index of the mesh in question. For a processor, this is its rank in the MESH_ACROSS_COMM communicator.
meshes: The number of meshes. This should be the value of the runtime parameter meshCopyCount, or equivalently the number of processors in the MESH_ACROSS_COMM communicator.

6.7.3 Example

In this example the global array FOO has eight elements, but there are three meshes, so two of the meshes will receive three elements of the array and one will get two. How that distribution is decided is hidden from the user. The output datasets will contain variables foo1 ...foo8.

Config:

NONREP MASS_SCALAR FOO 3 numFoo foo?

flash.par:

meshCopyCount = 3
numFoo = 8

Fortran 90:

#include "Flash.h"

! this shows how to iterate over the UNKs corresponding to this 
! processor's subset of FOO
integer :: nfooglob, nfooloc ! number of foo vars, global and local
integer :: mesh, nmesh ! this mesh number, and total number of meshes
integer :: fooloc, fooglob ! local and global foo indices
integer :: unk


call Driver_getMype(MESH_ACROSS_COMM, mesh)
call Driver_getNumProcs(MESH_ACROSS_COMM, nmesh)
call RuntimeParameters_get(FOO_NONREP_RPCOUNT, nfooglob)
nfooloc = NONREP_NLOCS(mesh, nmesh, nfooglob)

! iterate over the local subset for this mesh
do fooloc=1, nfooloc
    ! get the location in UNK
    unk = FOO_NONREP_LOC2UNK(fooloc)
    ! get the global index
    fooglob = NONREP_LOC2GLOB(fooloc, mesh, nmesh)

    ! you have what you need, do your worst...
end do