Function PGABuildDatatypeHeader

Function Documentation

int PGABuildDatatypeHeader(PGAContext *ctx, int p, int pop, int *counts, MPI_Aint *displs, MPI_Datatype *types)

Common part for building an MPI datatype for an individual.

Description

Returns by side effect a partially filled array of counts, displs, types. The returned index will be max PGA_MPI_HEADER_ELEMENTS. This means callers may use a statically allocated buffer.

Example

PGAContext *ctx;
int idx = 0;
int counts [PGA_MPI_HEADER_ELEMENTS + ...];
int displs [PGA_MPI_HEADER_ELEMENTS + ...];
MPI_Datatype types [PGA_MPI_HEADER_ELEMENTS + ...];

...
idx = PGABuildDatatypeHeader (ctx, counts, displs, types);
// Fill rest of counts, displs, types here and build datatype
counts [idx] =
displs [idx] =
types  [idx] =
idx++;
...

Parameters:

  • ctx – context variable

  • p – index of string

  • pop – symbolic constant of the population string p is in

  • counts – Number of elements in each block

  • displs – byte displacement array pointer

  • types – type elements

Returns:

The index of the next-to-be-filled counts, displs, types