MPIScattervconst

MPIScattervconst is a term used in some MPI-related codebases to denote a variant of the Scatterv operation in which the send buffer is treated as const. It is not part of the official MPI standard and does not appear in the MPI-3 or MPI-4 specifications. In practice, developers either use MPI_Scatterv with a const-qualified send buffer or provide a language-specific wrapper that enforces const-c correctness.

A representative, language-dependent signature might be:

int MPIScattervconst(const void sendbuf, const int sendcounts, const int displs, MPI_Datatype sendtype, void recvbuf, int recvcount, MPI_Datatype recvtype, int root, MPI_Comm comm);

Here the sendbuf is const, while recvbuf is non-const because it receives data. The remaining parameters follow the standard MPI_Scatterv semantics.

Semantics: MPIScattervconst distributes data from the root process to all processes in the communicator, with varying counts per process, as specified by sendcounts and displs. Each process receives data into its recvbuf with type and count specified by recvtype and recvcount. The key distinction implied by the name is that the root’s send buffer must not be modified by the scatter operation.

Usage considerations: Because MPIScattervconst is not a standard function, portability depends on the presence of a compatible wrapper or library. In portable code, programmers typically rely on MPI_Scatterv and ensure the actual data passed as sendbuf is treated as const at the call site, or they implement a similar interface in a wrapper that enforces const correctness.

See also: MPI_Scatterv, MPI_Gatherv, MPI_Bcast, const correctness in MPI.